OCS Study

BOEM 2016-021

Exploration and Research of Northern Gulf of Mexico 

Deepwater Natural and Artificial Hard-Bottom Habitats 

with Emphasis on Coral Communities: Reefs, Rigs,

and Wrecks—“Lophelia II”

Volume I: Technical Report

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Lophelia II - Field Operations October 2008 - July 2012

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U.S. Department of the Interior

Bureau of Ocean Energy Management

Gulf of Mexico OCS Region

OCS Study

BOEM 2016-021

Exploration and Research of Northern Gulf of 

Mexico Deepwater Natural and Artificial 

Hard-Bottom Habitats with Emphasis on 

Coral Communities: Reefs, Rigs, and 

Wrecks—“Lophelia II”

Final Report

Authors

James M. Brooks

Charles Fisher

Erik Cordes

Iliana Baums

Bernie Bernard

Robert Church

Peter Etnoyer

Chris German

Elizabeth Goehring

Ian MacDonald

Harry Roberts

Tim Shank

Dan Warren

Susan Welsh

Gary Wolff

Douglas Weaver

Prepared under BOEM Contract

M08PC20028

TDI-Brooks International Inc.

14391 South Dowling

College Station, TX 77845

Published by

U.S. Department of the Interior

Bureau of Ocean Energy Management New Orleans 

Gulf of Mexico OCS Region April 2016 

DISCLAIMER

This report was prepared under contract between the Bureau of Ocean Energy Management, 

(BOEM, previously the Minerals Management Service [MMS], then the Bureau of Ocean Energy 

Management, Regulation and Enforcement [BOEMRE]) and TDI-Brooks International, Inc. (TDIBI). Study concept, oversight, and funding were provided by the US Department of the Interior, 

Bureau of Ocean Energy Management, Environmental Studies Program, Washington, DC, under 

Contract Number M08PC20028. This report has been technically reviewed by BOEM and it has 

been approved for publication. The views and conclusions contained in this document are those of 

the authors and should not be interpreted as representing the opinions or policies of the US 

Government, nor does mention of trade names or commercial products constitute endorsement or 

recommendation for use.

REPORT AVAILABILITY

To download a PDF file of this Environmental Studies Program report, go to the US Department 

of the Interior, Bureau of Ocean Energy Management, Environmental Studies Program 

Information System website and search on OCS Study BOEM 2016-021. Copies can also be 

viewed at selected Federal Depository Libraries. See http://www.gpo.gov/libraries/. In the near 

future, you will also be able to get this report from the National Technical Information Service at 

the address below.

U.S. Department of the Interior

Bureau of Ocean Energy Management

Gulf of Mexico OCS Region

Public Information Office (MS GM 355A)

1201 Elmwood Park Blvd.

New Orleans, Louisiana 70123-2394

Phone: (504) 736-2519, 1-800-200-GULF

Fax: (504) 736-2620

U.S. Department of Commerce

National Technical Information Service

5301Shawnee Rd.

Springfield, Virginia 22312

Phone: (703) 605-6000,1-800-553-6847

Fax: (703) 605-6900

Web site: http://www.ntis.gov/

CITATION

Brooks, J.M., C. Fisher, H. Roberts, E. Cordes, I. Baums, B. Bernard, R. Church, P. Etnoyer, C.

German, E. Goehring, I. McDonald, Harry Roberts, T. Shank, D. Warren, S. Welsh, G. Wolff, 

D. Weaver. 2015. Exploration and research of northern Gulf of Mexico deepwater natural and 

artificial hard-bottom habitats with emphasis on coral communities: Reefs, rigs, and wrecks—

“Lophelia II” Final report. U.S. Dept. of the Interior, Bureau of Ocean Energy Management, 

Gulf of Mexico OCS Region, New Orleans, LA. OCS Study BOEM 2016-021. 628 p.

i

TABLE OF CONTENTS

1 Introduction ............................................................................................................................... 1

1.1 Overview ........................................................................................................................ 1

1.2 Background .................................................................................................................... 1

1.2.1 Deep-water Hard -Ground Communities.......................................................... 2

1.2.2 Deep-water Coral Biology and Ecology........................................................... 3

1.2.3 Deep-sea Environmental Issues and Impacts.................................................... 5

1.3 Objectives of the Project ................................................................................................ 7

2 Study Sites and Field Activity Overview.................................................................................. 8

2.1 Site Selection.................................................................................................................. 8

2.2 Cruise Overviews......................................................................................................... 10

2.2.1 Cruise 1: NOAA Ship Nancy Foster and SeaEye Falcon ROV..................... 11

2.2.2 Cruise 2: RV Brooks McCall and AUV Sentry .............................................. 14

2.2.3 Cruise 3: NOAA Ship Ronald H. Brown and the Jason II ROV.................... 17

2.2.4 Cruise 4: NOAA Ship Ronald H. Brown and the Jason II ROV.................... 20

2.2.5 Cruise 5: RV Brooks McCall and ROV Kraken II ......................................... 21

2.3 Overviews of Sites Visited by ROVs during the Time Period of this Project ............. 23

2.3.1 Project Study Sites (Sorted by Depth) ............................................................ 23

2.3.1.1 GC140 (250 m depth) ..................................................................... 23

2.3.1.2 VK 906/862 (320 to 400 m depth).................................................. 24

2.3.1.3 GB299 (340 – 510 m depth) ........................................................... 26

2.3.1.4 West Florida Slope (400 – 450 m depth)........................................ 31

2.3.1.5 MC751 (450 to 465 m depth).......................................................... 34

2.3.1.6 VK826 (450 – 530 m depth) ......................................................... 37

2.3.1.7 GC234 (500 – 550 m depth) ........................................................... 39

2.3.1.8 GB535 (515 – 540 m depth) ........................................................... 40

2.3.1.9 GC235 (520 m depth) ..................................................................... 43

2.3.1.10 GC354 (525 m depth) ..................................................................... 45

2.3.1.11 GB201 (525 m depth) ..................................................................... 45

2.3.1.12 EW1009 (560 m depth)................................................................... 47

2.3.1.13 MC539 (630 m depth).................................................................... 47

2.3.1.14 MC885 (650 m depth).................................................................... 47

2.3.1.15 GC246 (770 – 860 m depth) ........................................................... 48

2.3.1.16 GC249 (780 - 820 m depth)............................................................ 49

2.3.1.17 AT47 (835 - 860 m depth) .............................................................. 50

2.3.1.18 MC118 (880 m depth)..................................................................... 54

2.3.1.19 GC338 Site Summary (900 m depth).............................................. 55

2.3.1.20 MC294 Site I (1350 – 1400 m depth) ............................................. 57

2.3.1.21 MC388/294 (1370 – 1800 m depth)............................................... 58

2.3.1.22 GC852 (1400 m depth) ................................................................... 61

2.3.1.23 DC583 (2,200 – 2,500 m depth) ..................................................... 64
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2.3.1.24 DC673 (2,250 to 2,600 m depth) .................................................... 67

2.3.2 Other Coral Sites Discovered Since the DWH Incident (Sorted by Depth) ... 69

2.3.2.1 MC159/203 (950 m depth).............................................................. 70

2.3.2.2 MC036 (1110 – 1120 m depth)....................................................... 70

2.3.2.3 MC506 (1,040 m depth).................................................................. 72

2.3.2.4 AT357 (1,050 m depth)................................................................... 73

2.3.2.5 MC297 (1,580 m depth)................................................................. 75

2.3.2.6 MC388 (1,840 – 1,960 m depth).................................................... 76

3 Oceanographic and Geologic Setting ...................................................................................... 78

3.1 The Carbonate System and pH..................................................................................... 78

3.1.1 Introduction to Carbonate Testing Performed ................................................ 78

3.1.2 Methods of Carbonate Sampling and Analysis............................................... 78

3.1.2.1 Sample Collection ........................................................................... 78

3.1.2.2 Analytical Methods......................................................................... 79

3.1.2.3 Statistical Analyses ......................................................................... 80

3.1.3 Results and Discussion of Carbonate Study ................................................... 80

3.1.3.1 Total Alkalinity and pH in Surface Waters..................................... 80

3.1.3.2 Total alkalinity and pH in the Deep GoM....................................... 81

3.1.3.3 Aragonite Saturation State .............................................................. 83

3.2 Currents Associated with VK826 and GC852 and Implications for Larval 

Dispersal....................................................................................................................... 87

3.2.1 Introduction to Current Tests Performed ........................................................ 87

3.2.2 Deep Mooring Observations at Two Lophelia pertusa Sites.......................... 87

3.2.2.1 Overview......................................................................................... 87

3.2.2.2 Green Canyon 852 .......................................................................... 89

3.2.2.2.1 Historical Observations.................................................. 89

3.2.2.2.2 Mooring Data Analyses................................................. 90

3.2.2.3 Vioska Knoll 826 ............................................................................ 95

3.2.2.3.1 Historical Observations.................................................. 95

3.2.2.3.2 Mooring Data Analyses................................................. 96

3.2.3 Summary of Deep Water Currents Analysis................................................. 103

3.3 Time Series Analysis of Particulate Organic Input .................................................... 103

3.3.1 Objective of Mass Flux Testing.................................................................... 103

3.3.2 Deployment of Sediment Traps.................................................................... 103

3.3.3 Recovery of Sediment Traps......................................................................... 105

3.3.4 Results of Mass Flux Tests........................................................................... 106

3.4 Larval Flux to Coral Sites - Sediment Trap Results................................................... 108

3.4.1 Biogeochemical Analyses from VK826 ....................................................... 110

3.4.2 Larval Composition and Abundance from VK826....................................... 112

4 Community Structure, Biodiversity, and Biogeography....................................................... 116

4.1 Insights into Community Structure, Biodiversity and Biogeography from Analysis 

of Large-scale Phototransects..................................................................................... 117

4.1.1 Introduction................................................................................................... 117

4.1.2 Methods......................................................................................................... 117

4.1.2.1 Field Methods ............................................................................... 117
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4.1.2.2 Analytical Methods....................................................................... 119

4.1.3 Results........................................................................................................... 122

4.1.3.1 Live-to-Dead Ratios...................................................................... 122

4.1.3.2 Description of Communities......................................................... 123

4.1.3.3 Mobile Fauna ................................................................................ 124

4.1.4 Discussion..................................................................................................... 125

4.2 Insights into Community Structure, Biodiversity and Biogeography from 

Analyses of Photomosaics.......................................................................................... 126

4.2.1 Introduction................................................................................................... 126

4.2.2 Methods......................................................................................................... 127

4.2.2.1 Selection of Areas for Mosaics..................................................... 127

4.2.2.2 Image Collection ........................................................................... 128

4.2.2.3 Creation of Mosaics ...................................................................... 129

4.2.2.4 Digitizing Mosaics........................................................................ 129

4.2.2.5 Georeferencing between Years..................................................... 130

4.2.2.6 GIS and Statistical Comparisons................................................... 131

4.2.3 Results and Discussion ................................................................................. 131

4.2.3.1 Summaries of Photomosaics of Coral Communities .................... 131

4.2.3.1.1 GC140: Mosaic Marker W, 2010 (only)...................... 132

4.2.3.1.2 VK862: Mosaic Marker R, 2010 (only)....................... 133

4.2.3.1.3 VK862: Mosaic Marker T, 2010 (only)....................... 134

4.2.3.1.4 GB299: Mosaic Marker B............................................ 135

4.2.3.1.4.1 GB299: Mosaic Marker B, 2009............. 135

4.2.3.1.4.2 GB299: Mosaic Marker B, 2010............. 135

4.2.3.1.5 GB299: Mosaic Marker D ........................................... 136

4.2.3.1.5.1 GB299: Mosaic Marker D, 2009. ........... 136

4.2.3.1.5.2 GB299: Mosaic Marker D, 2010 ............ 137

4.2.3.1.6 VK906: Mosaic Marker J ............................................ 138

4.2.3.1.6.1 VK906: Mosaic Marker J, 2009.............. 138

4.2.3.1.6.2 VK906: Mosaic Marker J, 2010.............. 138

4.2.3.1.7 VK906: Mosaic Marker L............................................ 139

4.2.3.1.7.1 VK906: Mosaic Marker L, 2009............. 139

4.2.3.1.7.2 VK906: Mosaic Marker L, 2010............. 140

4.2.3.1.8 VK906: Mosaic Marker Y, 2010 (only) ...................... 141

4.2.3.1.9 MC751: Mosaic Marker G........................................... 141

4.2.3.1.9.1 MC751: Mosaic Marker G, 2009............ 142

4.2.3.1.9.2 MC751: Mosaic Marker G, 2010............ 142

4.2.3.1.10 MC751: Mosaic Marker H1......................................... 143

4.2.3.1.10.1 MC751: Mosaic Marker H1, 2009.......... 143

4.2.3.1.10.2 MC751: Mosaic Marker H1, 2010.......... 144

4.2.3.1.11 MC751: Mosaic Marker H2......................................... 145

4.2.3.1.11.1 MC751: Mosaic Marker H2, 2009.......... 145

4.2.3.1.11.2 MC751: Mosaic Marker H2, 2010.......... 146

4.2.3.1.12 VK826: Mosaic Marker M .......................................... 147

4.2.3.1.12.1 VK826: Mosaic Marker M, 2009............ 147

4.2.3.1.12.2 VK826: Mosaic Marker M, 2010............ 148
iv

4.2.3.1.13 VK826: Mosaic Marker N........................................... 148

4.2.3.1.13.1 VK826: Mosaic Marker N, 2009. ........... 148

4.2.3.1.13.2 VK826: Mosaic Marker N, 2010 ............ 149

4.2.3.1.14 VK826: Mosaic Marker O........................................... 150

4.2.3.1.14.1 VK826: Mosaic Marker O, 2009 ............ 150

4.2.3.1.14.2 VK826: Mosaic Marker O, 2010 ............ 151

4.2.3.1.15 VK826: Mosaic Marker Q........................................... 152

4.2.3.1.15.1 VK826: Mosaic Marker Q, 2009 ............ 152

4.2.3.1.15.2 VK826: Mosaic Marker Q, 2010 ............ 152

4.2.3.1.16 GB535: Mosaic Marker C............................................ 153

4.2.3.1.16.1 GB535: Mosaic Marker C, 2009............. 153

4.2.3.1.16.2 GB535: Mosaic Marker C, 2010............. 154

4.2.3.1.17 GB535: Mosaic Marker E............................................ 155

4.2.3.1.17.1 GB535: Mosaic Marker E, 2009............. 155

4.2.3.1.17.2 GB535: Mosaic Marker E, 2010............. 155

4.2.3.1.18 GC354: Mosaic Marker V, 2010 (only)....................... 156

4.2.3.1.19 MC885: Mosaic Marker U, 2010 (only)...................... 157

4.2.3.1.20 AT047: Mosaic Marker A, 2009 (only)....................... 158

4.2.3.1.21 MC118: Mosaic Markers T1 and T2, 2010 (only)....... 158

4.2.3.1.22 MC118: Mosaic Marker X, 2010 (only)...................... 159

4.2.3.1.23 MC294/338: Mosaic Marker AA, 2010 (only)............ 160

4.2.3.1.24 GC852: Mosaic Marker 5, 2009 (only) ....................... 160

4.2.3.2 Mosaics Imaged from a Vertical Perspective: .............................. 161

4.2.3.2.1 Vertical Mosaic F - J2-460 - GB535 - Heading 309 ̊ 

(8/28/09)....................................................................... 161

4.2.3.2.2 Vertical Mosaic 39 - J2-532 - GC140 - Heading 272 ̊ 

(10/22/10)..................................................................... 162

4.2.3.2.3 Vertical Mosaic T1-T2 - J2-538 – MC118 - Heading 

108 ̊ (10/30/10) ............................................................ 163

4.2.3.2.4 Vertical Mosaic X - J2-538 - MC118 – Heading 34 ̊ 

(10/28/10)..................................................................... 164

4.2.3.3 Comparison among Sites .............................................................. 165

4.2.3.4 Fidelity of Solitary and Mobile Fauna to Substratum Types........ 172

4.2.3.5 Temporal Change in Communities between Years....................... 179

4.2.4 Strengths and Weaknesses of Mosaics for the Study of Deep-sea Corals 

and Communities.......................................................................................... 182

4.3 Insights into Community Structure, Biodiversity and Biogeography from 

Analyses of Quantitative Collections......................................................................... 183

4.3.1 Quantitative Collection Methods.................................................................. 183

4.3.2 Quantitative Collection Results and Discussion........................................... 184

4.4 Biodiversity and Fidelity of Coral Associates............................................................ 188

4.4.1 Introduction................................................................................................... 188

4.4.2 Methods......................................................................................................... 190

4.4.2.1 Coral Associate Sample Collection for Image Reference............. 190

4.4.2.2 Analysis of Reference Sample Collections................................... 191

4.4.2.3 Lophelia II 2009 Video Analysis.................................................. 191
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4.4.2.4 Multivariate Analysis.................................................................... 191

4.4.3 Results........................................................................................................... 192

4.4.3.1 Coral-Associate Composition and Distribution ............................ 192

4.4.3.2 Multivariate Analysis.................................................................... 195

4.4.3.2.1 Assessing associates as indicators of coral ecosystem 

health 196

4.4.4 Discussion..................................................................................................... 197

4.4.4.1 Taxonomic Composition and Associations................................... 197

4.4.4.2 Regional Patterns .......................................................................... 198

4.4.4.3 Depth Patterns............................................................................... 199

4.5 Use of Imagery as Baseline Data for Study of Temporal Change in Coral 

Communities .............................................................................................................. 200

5 Phylogenetic Diversity and Connectivity.............................................................................. 202

5.1 Octocoral Community Structure and Phylogenetic Diversity.................................... 202

5.1.1 Background................................................................................................... 202

5.1.2 Methods......................................................................................................... 203

5.1.2.1 Sample Collections ....................................................................... 203

5.1.2.2 Molecular Barcoding Methods...................................................... 204

5.1.2.3 Community Structure Analyses .................................................... 205

5.1.2.4 Phylogenetic Diversity Analyses .................................................. 205

5.1.3 Results and Discussion ................................................................................. 205

5.1.3.1 Overview....................................................................................... 205

5.1.3.2 New Records and New Species .................................................... 206

5.1.3.3 Molecular Barcoding..................................................................... 209

5.1.3.4 Diversity and Community Structure ............................................. 210

5.1.3.4.1 α-Diversity ................................................................... 210

5.1.3.4.2 β-diversity.................................................................... 212

5.1.3.5 Regional Comparisons of Communities....................................... 216

5.1.4 Conclusions................................................................................................... 217

5.2 Genetic Diversity of Two Common Octocorals......................................................... 218

5.2.1 Background................................................................................................... 218

5.2.2 Methods......................................................................................................... 218

5.2.2.1 Morphological Identification ........................................................ 218

5.2.2.2 Phylogenetics ................................................................................ 218

5.2.2.2.1 Callogorgia.................................................................. 218

5.2.2.2.2 Paramuricea ................................................................ 219

5.2.2.3 Microsatellite Marker Development ............................................. 219

5.2.3 Results and Discussion ................................................................................. 221

5.2.3.1 Taxonomic Status and Phylogenetic Relationships ...................... 221

5.2.3.1.1 Callogorgia.................................................................. 221

5.2.3.1.2 Paramuricea ................................................................ 223

5.2.3.2 Microsatellite Analyses................................................................. 226

5.2.3.2.1 Callogorgia.................................................................. 226

5.2.4 Conclusions................................................................................................... 230

5.3 Black Coral Genetics and Connectivity ..................................................................... 231

5.3.1 Introduction................................................................................................... 231
vi

5.3.2 Methods......................................................................................................... 233

5.3.2.1 Sample Collection, DNA Extraction, Sequencing and 

Genotyping.................................................................................... 233

5.3.2.2 Phylogenetic and Population Genetic Analyses............................ 234

5.3.3 Results........................................................................................................... 235

5.3.4 Discussion..................................................................................................... 243

6 Trophic Studies...................................................................................................................... 246

6.1 Background ................................................................................................................ 246

6.2 Methods...................................................................................................................... 247

6.2.1 Sampling ....................................................................................................... 247

6.2.2 Stable Isotope Analysis................................................................................. 247

6.2.3 Statistical Analysis........................................................................................ 248

6.3 Results........................................................................................................................ 248

6.3.1 Interspecific and Spatial Variation in Coral Tissue Stable Isotope 

Compositions................................................................................................ 248

6.3.2 Corals with Paired Commensal Ophiuroids.................................................. 252

6.3.3 Macrofaunal Community Associated with Lophelia pertusa ....................... 256

6.4 Discussion .................................................................................................................. 256

6.4.1 Nutrition of deepwater corals........................................................................ 256

6.4.2 Nutritional Associations Between Corals and their Epizoic Ophiuroids...... 258

6.4.3 Nutritional Sources for Fauna Associated with Lophelia pertusa................ 258

7 Lophelia pertusa Laboratory Experiments............................................................................ 260

7.1 Introduction ................................................................................................................ 260

7.2 Development of Recirculating Aquaria for Experimentation with Deep-sea Corals. 262

7.2.1 Methods......................................................................................................... 262

7.2.1.1 Maintenance Aquaria Design and Setup....................................... 262

7.2.1.2 Experimental Aquaria Design and Setup ...................................... 263

7.2.1.3 Animal Collection, Maintenance, and Processing ........................ 264

7.2.1.4 Carbonate Chemistry Manipulations ............................................ 264

7.2.1.5 Dissolved Oxygen Manipulations................................................. 266

7.2.2 Results........................................................................................................... 266

7.2.2.1 Maintenance Aquaria .................................................................... 266

7.2.2.2 Experimental Aquaria ................................................................... 266

7.2.2.3 Animal Collection, Maintenance, and Processing ........................ 266

7.2.2.4 Carbonate Chemistry Manipulations ............................................ 267

7.2.2.5 Dissolved Oxygen Manipulations................................................. 268

7.2.3 Discussion..................................................................................................... 269

7.3 Observations of Fauna in Laboratory Aquaria ........................................................... 270

7.3.1 Lophelia pertusa ........................................................................................... 270

7.3.2 Coralliophila sp. ........................................................................................... 270

7.3.3 Eunice sp....................................................................................................... 270

7.4 pH Experiments.......................................................................................................... 271

7.4.1 Methods......................................................................................................... 271

7.4.1.1 Experimental Design and Setup.................................................... 271

7.4.1.2 Sample Collection, Preparation, and Maintenance ....................... 272
vii

7.4.1.3 Seawater Preparation and Analyses.............................................. 274

7.4.1.4 Survivorship Measurements.......................................................... 274

7.4.1.5 Growth Measurements.................................................................. 274

7.4.1.6 Statistical Analyses ....................................................................... 275

7.4.2 Results........................................................................................................... 275

7.4.3 Discussion..................................................................................................... 281

7.5 Temperature Experiments .......................................................................................... 282

7.5.1 Methods......................................................................................................... 282

7.5.1.1 Experimental Design and Setup.................................................... 282

7.5.2 Results and Discussion ................................................................................. 282

7.6 Dissolved oxygen experiments................................................................................... 286

7.6.1 Methods......................................................................................................... 286

7.6.1.1 Experimental Design and Setup.................................................... 286

7.6.2 Results and Discussion ................................................................................. 287

8 Biological Communities on Artificial Substrates, with Emphasis on Lophelia pertusa....... 290

8.1 Introduction: ............................................................................................................... 290

8.2 Overview of Each Platform Studied:.......................................................................... 291

8.2.1 Neptune ......................................................................................................... 291

8.2.2 Pompano ....................................................................................................... 291

8.2.3 Petronius ....................................................................................................... 294

8.2.4 Baldpate ........................................................................................................ 295

8.2.5 Jolliet............................................................................................................. 295

8.2.6 Ram-Powell................................................................................................... 297

8.2.7 Cognac .......................................................................................................... 298

8.2.8 Zinc Subsea Installation................................................................................ 301

8.3 Growth Rates, Densities, and Distribution of Lophelia pertusa on Artificial 

Structures in the Gulf of Mexico................................................................................ 303

8.3.1 Abstract......................................................................................................... 303

8.3.2 Introduction................................................................................................... 304

8.3.3 Methods......................................................................................................... 305

8.3.4 Results........................................................................................................... 310

8.3.5 Discussion..................................................................................................... 316

9 VK906 Lophelia Mound Piston Core Analysis..................................................................... 320

9.1 Methods of Investigation............................................................................................ 325

9.1.1 Mound Discovery.......................................................................................... 325

9.1.1.1 Core Acquisition ........................................................................... 325

9.1.1.2 Core Analyses............................................................................... 326

9.1.1.2.1 Multisensor Core Logger............................................. 326

9.1.1.3 Digital Core Photography ............................................................. 330

9.1.1.4 Age Dating (Radiocarbon and U/Th)............................................ 330

9.1.1.5 Clay Mineralogy ........................................................................... 331

9.1.1.6 Elemental Analyses....................................................................... 331

9.1.1.7 Skeletal Density ............................................................................ 331

9.2 Initial Results.............................................................................................................. 331

9.2.1 Lithostratigraphy........................................................................................... 332
viii

9.2.2 Biostratigraphy and Age Dating ................................................................... 334

9.2.3 Skeletal Density ............................................................................................ 341

10 Archaeology .......................................................................................................................... 343

10.1 Introduction ................................................................................................................ 343

10.1.1 Overview....................................................................................................... 343

10.1.2 Archaeological Component Objectives ........................................................ 343

10.1.3 Project Organization ..................................................................................... 344

10.2 Geographic Overview................................................................................................. 344

10.3 Historical Background................................................................................................ 346

10.3.1 Maritime Activity in the Northern Gulf of Mexico 1800-1820.................... 346

10.3.1.1 Wooden Vessel Types................................................................... 349

10.3.1.2 Sheathing....................................................................................... 352

10.3.2 World War II in the Gulf of Mexico............................................................. 352

10.3.3 Oil and Gas Development and Shipwreck Discovery................................... 354

10.3.4 Regulatory Role of the BOEM and BSEE.................................................... 354

10.4 Methods...................................................................................................................... 355

10.4.1 Survey Methodology..................................................................................... 355

10.4.2 Archaeological Methods............................................................................... 355

10.4.2.1 Field Methods ............................................................................... 355

10.4.2.1.1 Reconnaissance Transects............................................ 356

10.4.2.1.2 Mosaic Transects ......................................................... 356

10.4.2.1.3 Biology Transects........................................................ 356

10.4.2.1.4 Close-Up Transects...................................................... 357

10.4.2.1.5 Artifact Recovery......................................................... 357

10.4.2.2 Post-Field Operations Archaeological Data Assessment.............. 357

10.4.3 Conservation Methods.................................................................................. 358

10.4.3.1 Field Conservation ........................................................................ 358

10.4.3.2 Laboratory Conservation............................................................... 358

10.5 Shipwreck Site Assessments...................................................................................... 359

10.5.1 Viosca Knoll Wreck Site............................................................................... 359

10.5.1.1 Historical Background of the Viosca Knoll Wreck ...................... 359

10.5.1.2 Field Investigations....................................................................... 359

10.5.1.2.1 Discovery and Exploration .......................................... 359

10.5.1.2.2 Viosca Knoll Wreck 2006 ROV Investigation (OCS 

Study MMS 2008-018)................................................ 363

10.5.1.2.3 Lophelia II: Reefs, Rigs, and Wrecks 2009 Field 

Cruise 363

10.5.1.3 Geographic Settings...................................................................... 364

10.5.1.4 Discussion of Archaeological Findings at the VK Wreck ............ 364

10.5.1.4.1 Physical Site................................................................. 364

10.5.1.4.2 Sheathing ..................................................................... 366

10.5.1.4.3 Bow 368

10.5.1.4.4 Stern 370

10.5.1.4.5 Rigging......................................................................... 375

10.5.1.4.6 Deck Beams Other Construction features.................... 377

10.5.1.4.7 Scattered Artifacts - Outlying Material ....................... 378
ix

10.5.1.5 Recovered Artifacts....................................................................... 381

10.5.1.6 Site Preservation ........................................................................... 384

10.5.2 7,000 Foot Wreck Site .................................................................................. 385

10.5.2.1 Historical Background of the 7,000 Foot Wreck .......................... 385

10.5.2.2 Field Investigations....................................................................... 385

10.5.2.2.1 Discovery and Exploration .......................................... 385

10.5.2.2.2 Woods Hole Oceanographic Institution 2009 AUV 

Survey .......................................................................... 386

10.5.2.2.3 Lophelia II: Rigs, Reefs, and Wrecks 2009 Field 

Cruise 387

10.5.2.3 Geographic Settings...................................................................... 388

10.5.2.4 Discussion of Archaeological Findings ........................................ 388

10.5.2.4.1 Physical Site................................................................. 388

10.5.2.4.2 Bow and Hull............................................................... 390

10.5.2.4.3 Stem and Head Knee.................................................... 391

10.5.2.4.4 Windlass....................................................................... 392

10.5.2.4.5 Rigging and Mast Components.................................... 394

10.5.2.4.6 Foremast Rigging......................................................... 396

10.5.2.4.7 Mainmast Rigging........................................................ 397

10.5.2.4.8 Mast Band and Yoke.................................................... 398

10.5.2.4.9 Sheathing ..................................................................... 399

10.5.2.4.10 Anchors..................................................................... 400

10.5.2.4.11 Wheel and Steering Machinery................................. 404

10.5.2.5 Artifacts......................................................................................... 407

10.5.2.5.1 Stove 407

10.5.2.5.2 Water Barrel................................................................. 407

10.5.2.5.3 Bottles and Containers................................................. 408

10.5.2.5.4 Hanging Knee: ............................................................. 408

10.5.2.5.5 Lantern......................................................................... 409

10.5.2.6 Recovered Artifacts....................................................................... 409

10.5.2.7 Site Preservation ........................................................................... 415

10.5.3 Ewing Bank Wreck Site ................................................................................ 415

10.5.3.1 Historical Background of the Ewing Bank Wreck........................ 415

10.5.3.2 Field Investigations....................................................................... 415

10.5.3.2.1 Discovery and Exploration .......................................... 415

10.5.3.2.2 C&C Technologies, Inc. 2007 AUV Survey ............... 417

10.5.3.2.3 Lophelia II: Rigs, Reefs, and Wrecks 2008 Field 

Cruise 418

10.5.3.2.4 2009 C&C Technologies, Inc. AUV Survey ............... 418

10.5.3.2.5 Lophelia II: Rigs, Reefs, and Wrecks 2009 Field 

Cruise 419

10.5.3.2.6 2012 C&C Technologies, Inc. AUV Survey ............... 421

10.5.3.3 Geographical Setting..................................................................... 421

10.5.3.4 Discussion of Archaeological Findings ........................................ 422

10.5.3.4.1 Physical Site................................................................. 422

10.5.3.4.2 Bow 429
x

10.5.3.4.3 Frames and Outer Planking.......................................... 431

10.5.3.4.4 Ceiling Planking .......................................................... 433

10.5.3.4.5 Stern 434

10.5.3.4.6 Fasteners ...................................................................... 435

10.5.3.4.7 Sheathing ..................................................................... 440

10.5.3.4.8 Miscellaneous Ship Components................................. 441

10.5.3.4.9 Artifacts ....................................................................... 446

10.5.3.5 Recovered Artifacts....................................................................... 448

10.5.3.6 Site Preservation ........................................................................... 454

10.5.4 Green Lantern Wreck Site ............................................................................ 454

10.5.4.1 Historical Background of the Green Lantern Wreck .................... 454

10.5.4.2 Field Investigations....................................................................... 454

10.5.4.2.1 Discovery and Exploration .......................................... 454

10.5.4.2.2 Lophelia II: Reefs, Rigs, and Wrecks 2008 Field 

Cruise 455

10.5.4.2.3 Lophelia II: Reefs, Rigs, and Wrecks 2009 Field 

Cruise 455

10.5.4.3 Geographical Setting..................................................................... 456

10.5.4.4 457

10.5.4.5 Discussion of Archaeological Findings ........................................ 457

10.5.4.5.1 Physical Site................................................................. 458

10.5.4.5.2 Sheathing ..................................................................... 458

10.5.4.5.3 The Bow....................................................................... 459

10.5.4.5.4 Rigging......................................................................... 461

10.5.4.5.5 Between the Bow and Stern......................................... 462

10.5.4.5.6 The Stern...................................................................... 464

10.5.4.6 Recovered Artifacts....................................................................... 466

10.5.4.7 Site Preservation ........................................................................... 470

10.5.5 Gulfoil wreck site.......................................................................................... 470

10.5.5.1 Historical Background of the Gulfoil............................................ 470

10.5.5.2 Field Investigations....................................................................... 475

10.5.5.2.1 Discovery and Exploration .......................................... 475

10.5.5.2.2 Lophelia II: Reefs, Rigs, and Wrecks 2008 Field 

Cruise 476

10.5.5.2.3 C-Surveyor III 2009 AUV Survey............................... 476

10.5.5.2.4 Lophelia II: Reefs, Rigs, and Wrecks 2010 Field 

Cruise 477

10.5.5.3 Geographical Setting..................................................................... 478

10.5.5.4 Discussion of Archaeological findings ......................................... 478

10.5.5.4.1 Physical Site................................................................. 478

10.5.5.5 Site Formation and Distribution.................................................... 485

10.5.5.6 Site Preservation ........................................................................... 489

10.5.6 Gulfpenn Wreck Site..................................................................................... 489

10.5.6.1 Historical Background of the Gulfpenn ........................................ 489

10.5.6.2 Field Investigations....................................................................... 492

10.5.6.2.1 Discovery and Exploration .......................................... 492
xi

10.5.6.2.2 2004 DeepWrecks I ROV Investigation ...................... 492

10.5.6.2.3 Lophelia II: Reefs, Rigs, and Wrecks 2008 Field 

Cruise 493

10.5.6.2.4 Lophelia II: Reefs, Rigs, and Wrecks 2009 Field 

Cruise 493

10.5.6.3 Geographical Setting..................................................................... 494

10.5.6.4 Discussion of Archaeological Finding.......................................... 494

10.5.6.4.1 Physical Site................................................................. 494

10.5.6.5 Site Preservation ........................................................................... 503

10.5.7 Deustche Kreigsmarine (DKM) U-166 Site ................................................. 503

10.5.7.1 Historical Background of DKM U-166 ........................................ 503

10.5.7.2 Field Investigations....................................................................... 508

10.5.7.2.1 Discovery and Exploration .......................................... 508

10.5.7.2.2 2001 Autonomous Underwater Vehicle (AUV) 

Survey .......................................................................... 508

10.5.7.2.3 2003 C & C Technologies, Inc./NOAA OE Site 

Investigations............................................................... 511

10.5.7.2.4 2004 Deepwrecks I Site Investigation ......................... 512

10.5.7.2.5 Lophelia II: Reefs, Rigs, and Wrecks 2010 Field 

Cruise 512

10.6 Conclusions................................................................................................................ 513

10.6.1 Viosca Knoll Wreck ...................................................................................... 513

10.6.2 7,000 Ft Wreck.............................................................................................. 514

10.6.3 Ewing Bank Wreck ....................................................................................... 514

10.6.4 Green Lantern Wreck ................................................................................... 514

10.6.5 Gulfoil Wreck................................................................................................ 515

10.6.6 Gulfpenn Wreck............................................................................................ 515

10.6.7 Site distribution equations............................................................................. 516

11 Education and Outreach ........................................................................................................ 517

11.1 Lophelia II Curriculum: Understanding Deep-Sea Coral Ecology ............................ 517

11.2 Ocean Literacy Principles and Fundamental Concepts.............................................. 517

11.3 Teacher Guide and Support Materials........................................................................ 518

11.4 Curriculum Testing..................................................................................................... 518

11.5 Dissemination............................................................................................................. 518

11.6 Video Production........................................................................................................ 519

11.6.1 Video Production Summary.......................................................................... 519

12 Improved Prediction of Cold-water Corals OCCURRENCE in the Gulf of Mexico .......... 523

12.1 Background ................................................................................................................ 523

12.2 Methods...................................................................................................................... 524

12.2.1 Occurrence Data............................................................................................ 524

12.2.2 Environmental Data ...................................................................................... 524

12.2.3 Model Generation and Evaluation ................................................................ 526

12.2.4 Niche Evaluation........................................................................................... 527

12.2.5 Niche Breadth: 1/B = Σpi2.......................................................................... 527

12.2.6 Predictive Modeling Program....................................................................... 528
xii

12.3 Results and Discussion............................................................................................... 528

12.3.1 Local Scale Models....................................................................................... 528

12.3.2 Callogorgia spp. Mosaic Models.................................................................. 544

12.3.3 Large-Scale Models...................................................................................... 547

13 Understanding Deep Coral Distribution Patterns.................................................................. 554

14 Commercial Fisheries in the Gulf of Mexico and Potential Impacts to Deepwater Corals .. 556

14.1 Introduction ................................................................................................................ 559

14.1.1 Overview....................................................................................................... 559

14.1.2 Overall Project Background.......................................................................... 559

14.1.3 Objectives of the Project............................................................................... 560

14.2 Deepwater Fisheries in the Gulf of Mexico ............................................................... 561

14.2.1 Background................................................................................................... 561

14.2.2 Deepwater Coral Ecosystems ....................................................................... 561

14.2.3 Lophelia pertusa distribution ........................................................................ 562

14.2.4 Commercial Fishing Activities and Data Acquisition .................................. 562

14.2.5 Deepwater Fishery Species........................................................................... 563

14.2.6 Historical Development of the Deepwater Grouper and Tilefish Fishery .... 569

14.2.7 Current status of the Deepwater Reef Fish Fishery ...................................... 569

14.2.8 History of the Deepwater Shrimp Fishery .................................................... 571

14.2.9 Current status of the Deepwater Invertebrate Fishery .................................. 571

14.2.10 Oculina Banks Ecosystem Impacts............................................................... 572

14.2.11 Coral Habitat HAPCs in the South Atlantic ................................................. 573

14.3 Summary .................................................................................................................... 573

14.4 References: ................................................................................................................. 575

15 References............................................................................................................................. 611
xiii

LIST OF FIGURES

Figure 2-1. Seismic seafloor amplitude anomaly distribution, from BOEM website. Over 

23,000 positive anomalies shown in red are potential hard grounds........................ 9

Figure 2-2. Bathymetric map of the northern Gulf of Mexico showing shipwrecks and oil or 

gas platforms of interest in Cruise 1....................................................................... 12

Figure 2-3. Cruise tracks for Leg 1 and Leg 2.............................................................................. 13

Figure 2-4. The AUV Sentry being recovered onto the Research Vessel (R/V) Brooks McCall

following a successful dive. ................................................................................... 14

Figure 2-5. Sites visited, Cruise 2................................................................................................. 16

Figure 2-6. Illustration of the Jason II/Medea ROV (WHOI)...................................................... 17

Figure 2-7. Lophelia II Cruise 3 track of Ronald H. Brown......................................................... 19

Figure 2-8. Cruise track for Cruise 4 on the NOAA Ship Ronald H. Brown. .............................. 21

Figure 2-9. Kraken II ROV being launched at the Jolliet Platform.............................................. 22

Figure 2-10. Cruise track for Cruise 5. ......................................................................................... 22

Figure 2-11. Small colonies of Lophelia, antipatharians, and gorgonians.................................... 25

Figure 2-12. Lophelia and the white form of Leiopathes. ............................................................ 26

Figure 2-13. Carbonate rubble and pavements with attached gorgonians and antipatharians...... 27

Figure 2-14. Carbonates with corals and sea anemones attached................................................. 28

Figure 2-15. Corals growing in what appears to be mud, but with carbonate rubble 

underneath .............................................................................................................. 28

Figure 2-16. A colony of the white color-morph of Leiopathes................................................... 29

Figure 2-17. Callogorgia spp. colonies with attached ophiuroids................................................ 30

Figure 2-18. Half meter wide holes at GB299.............................................................................. 31

Figure 2-19. Large Leiopathes colony. ......................................................................................... 32

Figure 2-20. Largely unoccupied substrate................................................................................... 32

Figure 2-21. Lophelia on the West Florida Slope......................................................................... 33

Figure 2-22. L. pertusa on the W. Fl. Slope. ................................................................................ 34

Figure 2-23. Lophelia pertusa and Lamellibrachia luymesi tube worms. .................................... 35

Figure 2-24. Paragorgia sp. coral on right side of image with multiple clonies of 

Paramuricea sp. ..................................................................................................... 36

Figure 2-25. Lophelia and Callogorgia colonies.......................................................................... 36

Figure 2-26. A large mound is colonized by red and orange Leiopathes sp., Eumunida picta, 

and live and dead Lophelia pertusa (VK826). ....................................................... 37
xiv

Figure 2-27. Thickets of Lophelia pertusa with Eumunida picta, Echinus urchins, and crinoid 

associates (VK826)................................................................................................. 38

Figure 2-28. School of Beryx splendens over L. pertusa with attached crinoid at VK826. ......... 38

Figure 2-29. Dead Lophelia accumulation with Hoplostethus sp................................................. 39

Figure 2-30. Callogorgia sp. and Asteroschema sp. along with some small cup corals. ............. 40

Figure 2-31. White sponges. ......................................................................................................... 41

Figure 2-32. Patchily distributed fauna on carbonate rubble........................................................ 42

Figure 2-33. Lophelia colonies. .................................................................................................... 42

Figure 2-34. L. pertusa rubble. ..................................................................................................... 43

Figure 2-35. Vestimentiferans Lamellibrachia luymesi and Seepiophila jonesi. ......................... 44

Figure 2-36. Primnoid gorgonians at GC235................................................................................ 44

Figure 2-37. A small octocoral colony in GB201. Note the high concentration of particulates 

in the water. ............................................................................................................ 46

Figure 2-38. The large black coral at GB201. .............................................................................. 46

Figure 2-39. Typical setting at MC885, including small tube worm aggregations and 

occasional colonies of Callogorgia americana delta. ............................................ 48

Figure 2-40. A dense field of dead Bathymodiolus mussels with disarticulated shells 

(GC246).................................................................................................................. 49

Figure 2-41. Bacterial mats and purple ciliates cover a number of Lamellibrachia luymesi 

tube worms and Bathymodiolus childressi mussels (GC249). ............................... 50

Figure 2-42. Extensive and dense clam beds. ............................................................................... 51

Figure 2-43. Articulated and disarticulated clam shells with some live mussels. ........................ 52

Figure 2-44. Large standing colony of Madrepora. ..................................................................... 53

Figure 2-45. Dead Madrepora, areas of live coral and golden crabs (Chaceon).......................... 53

Figure 2-46. A single large colony of Paramuricea sp. is seen along with a number of its 

associated Astroschema sp. (MC118). ................................................................... 54

Figure 2-47. Carbonate rubble and clam shells scattered over the seafloor. ................................ 55

Figure 2-48. Callogorgia with attached ophiuroids...................................................................... 56

Figure 2-49. Paramuricea with attached ophiuroids. ................................................................... 56

Figure 2-50. Sporadic bacterial mats at MC294. .......................................................................... 57

Figure 2-51. Small tube worm aggregations at MC294................................................................ 58

Figure 2-52. Photomosaic of the central area at MC294/338 with each coral identified for 

monitoring. ............................................................................................................. 60

Figure 2-53. Example of a coral (A10) imaged during 6 different visits to the MC338/294 

site. ......................................................................................................................... 61
xv

Figure 2-54. Coral colonization at central part of GC852. ........................................................... 62

Figure 2-55. Iridogorgia and bamboo corals at the central portion of the site............................. 62

Figure 2-56. Steep slope on the flank of the northern end of the GC852 site. ............................. 63

Figure 2-57. Isolated octocoral colonies at northern end of GC852............................................. 63

Figure 2-58. Tubeworms near the base of the outcrop. ................................................................ 64

Figure 2-59. High density seep community.................................................................................. 65

Figure 2-60. The base of the escarpment. ..................................................................................... 66

Figure 2-61. Paramuricid hosting a single Asteroschema ophiuroid. ........................................... 66

Figure 2-62. Bamboo coral colonies............................................................................................. 67

Figure 2-63. An octopus takes refuge in a dense tube worm bush and mussel bed (DC673). ..... 68

Figure 2-64. A single Iridogorgia sp. is seen settled on a rocky outcrop surrounded by a few 

small colonies of Paramuricea biscaya (DC673). ................................................. 69

Figure 2-65. Swiftia cf. koreni with longline at MC159/203........................................................ 70

Figure 2-66. Paramuricea B3 with attached ophiuroid near marker M18 at MC036. ................. 71

Figure 2-67. Chrysogorgia sp at MC036...................................................................................... 72

Figure 2-68. Paramuricea sp B3 from MC506. Note long line in lower right and colony in 

forefront.................................................................................................................. 73

Figure 2-69. Paramuricea sp with attached ophiuroid brittle stars at AT 357. ............................ 74

Figure 2-70. The edge of the large Madrepora reef with a Paramuricea type B3 colony. 

Associates include a large orange basket star, galatheid crabs, and numerous 

ophiuroids............................................................................................................... 74

Figure 2-71. Paramuricea biscaya at MC297. ............................................................................. 75

Figure 2-72. Unidentified octocoral at MC297............................................................................. 76

Figure 2-73. Whip coral (Stichopathes sp.), Paramuricea biscaya, black coral (Bathypathes

sp.), and encrusting Clavularis rudis octocoral in MC388. ................................... 77

Figure 2-74. Unidentified white octocoral in front of Paramuricea biscaya at MC388. ............. 77

Figure 3-1. Seven Niskin bottle array fitted to ROV Jason during the 2010 Lophelia II 

cruise. ..................................................................................................................... 79

Figure 3-2. Water column profile of normalized total alkalinity (nTA) (μmol kg-1) from 0 to 

1600 m.................................................................................................................... 82

Figure 3-3. Water column profile of pH (total hydrogen scale) from 0 to 1600 m. .................... 82

Figure 3-4. Water column profile of the aragonite saturation state (Ωarag) from 0 to 1600 m. 

Solid line represents the function Ωarag = aebx(depth) + c. Dashed line represents 

Ωarag = 1.0............................................................................................................. 85
xvi

Figure 3-5. Distributions of (A) normalized total alkalinity (nTA) (μmol kg-1), (B) pH (total 

hydrogen scale), (C) carbonate ion concentration ([CO32-]) (μmol kg-1), and 

(D) the aragonite saturation state (Ωarag). Areas in white represent no data. ....... 86

Figure 3-6. Bottom bathymetric contours (meters) in the GoM. The mooring sites are 

indicated with red crosses. The location of the Macondo 252 well is indicated 

with a blue circle. ................................................................................................... 88

Figure 3-7. Current speed during the first 21 days of the deployment at 450 m (red) and 

ADCP bin 1 (blue) at 444 m................................................................................... 88

Figure 3-8. Daily averaged 40-hour low-pass filtered current vectors for CM01 and CM00. .... 91

Figure 3-9. 40- hour low-pass filtered temperature records at CM01 (top) and CM00 

(bottom).................................................................................................................. 91

Figure 3-10. Current vectors (top), corresponding current direction (blue), and temperature 

(green) (bottom) for CM01 days 1-60.................................................................... 92

Figure 3-11. Current vectors (top), corresponding current direction (blue), and temperature 

(green) (bottom) for CM00 days 1-60.................................................................... 92

Figure 3-12. Current vectors measured at CM01 (top) and CM00 (bottom) on days 280-340. ... 93

Figure 3-13. Standard deviation ellipses (left) and progressive vector diagrams (right) for 

CM01 (red) and CM00 (black)............................................................................... 93

Figure 3-14. Spectra of CM00 (top) and CM01 (bottom) u-velocity (blue) and v-velocity 

(green) smoothed with a 5 Hanning window. ........................................................ 94

Figure 3-15. Rotary Spectra at CM01 (left) and CM00 (right)..................................................... 95

Figure 3-16. Stick plots for ADCP bins 1 (444 m), 11 (424 m), 21 (404 m), and 31 (384 m)..... 99

Figure 3-17. Contours of U- and V-components of velocity (cm/s ) for ADCP bins 1-37. ......... 99

Figure 3-18. Standard deviation ellipses for CM03 (446 m), ADCP bin 1(444 m), and ADCP 

bin 37 (372 m). ..................................................................................................... 100

Figure 3-19. Progressive vector diagram for ADCP at 5 depth levels........................................ 100

Figure 3-20. Spectra of u-velocity (blue) and v-velocity (green) for bins 1 (446 m) and 37 

(372 m) smoothed with a 5 Hanning window. ..................................................... 101

Figure 3-21. Rotary Spectra for the uppermost ADCP bin 37 at 372 m (left) and for the 

current meter at 450.3 m (right). .......................................................................... 101

Figure 3-22. EOFs for ADCP bins 1-37 velocity components at VK826. Modes 1-3 are 

indicated by red, blue, and green lines, respectively............................................ 102

Figure 3-23. 40-HLP temperature from CM03 at 450 m and 40-HLP u-component of velocity 

from ADCP bin 37 (372m)................................................................................... 102

Figure 3-24. PARFLUX sediment traps during deployment. ..................................................... 104

Figure 3-25. Schematic of 21-cup time-series sediment trap moorings used for this project .... 104
xvii

Figure 3-26. Sediment Trap Mooring 1 (Site MC751) deployed at 28°11.64’N, 089° 47.90’W 

on 09/01/09........................................................................................................... 105

Figure 3-27. Sediment Trap Mooring 2 (Site VK826) deployed at 29° 09.63’N, 088° 

01.13’W on 09/04/09............................................................................................ 105

Figure 3-28. Time-series data, 2009-10. Left: Mass Flux data (both sites); Right: Four 

component analysis (VK826)............................................................................... 106

Figure 3-29. Current meter data displayed as a stick diagram showing direction (stick 

orientation) and speed (stick length) from the VK826 site. (Data for MC751 

not shown). Note that maximum velocities occur in winter 2009-10 and much 

calmer conditions prevailed in spring-summer 2010. .......................................... 107

Figure 3-30. Time-series data, 2009-10 for (a) POC concentrations; (b) Ba concentrations; 

(c) C:N molar ratios at VK826. ............................................................................ 108

Figure 3-31a,b. Diagrammatic views of (a) a McLane Parflux sediment trap and (b) the 

rosette of 500 ml collection bottles and autonomously rotated by a motor at the 

base of the funnel ................................................................................................. 109

Figure 3-32. Total mass flux (mg/m2/day) from sediment trap series at Viosca Knoll. 

Shaded area indicates timing and duration of oil spill. ........................................ 110

Figure 3-33. Particulate inorganic carbon (PIC), (mg/m2/day) from sediment trap series at 

Viosca Knoll. Shaded area indicates timing and duration of oil spill. ................ 111

Figure 3-34. Particulate organic carbon (POC), (mg/m2/day) from sediment trap series at 

Viosca Knoll. Shaded area indicates timing and duration of oil spill. ................ 111

Figure 3-35. C/N, as calculated using organic carbon from sediment trap series at Viosca 

Knoll. Shaded area indicates timing and duration of oil spill. ............................ 112

Figure 3-36. Number of individual specimens collected over time. The most abundant 

organisms in the 1-5 mm fraction were pteropod shells (red) and copepods 

(green). Shaded area indicates timing and duration of oil spill........................... 113

Figure 3-37. Number of individual specimens collected over time. The most abundant 

organisms in the <1 mm fraction are gastropod shells (violet) and bivalve shells 

(blue). Numbers were pooled from the 300 μm-1mm and 63-300 μm fractions. 113

Figure 3-38. The extent of surface slicks on May 2, 2010. Red stars indicate position of 

sediment traps....................................................................................................... 115

Figure 4-1. Map of regions surveyed using the AUV and ROV. VK826 in 2009 and 2010 (A), 

VK906 (B), and GB535 (C). Transects from 2010 are denoted by green 

(starting) and red (stopping) markers. .................................................................. 118

Figure 4-2. Average percentage of live coral cover observed at project sites VK826 and 

VK906 (None observed at GB535). The 2009 and 2010 results are for surveys 

of different regions of the VK826 site. See Figure 4-1 for detail. ...................... 122

Figure 4-3. Rarefaction curves for photographic sampling of mobile fauna observed in 

photographic transects at three project sites: A, VK826 (2009); B, VK826 

(2010); C, VK906; D, GB535. ............................................................................. 125
xviii

Figure 4-4. Key for all digitized photomosaics in this section (4.2.3.1)..................................... 132

Figure 4-5. Photomosaic of Marker W in 2010 and digitization of this mosaic......................... 133

Figure 4-6. Photomosaic of Marker R in 2010 and digitization of this mosaic.......................... 134

Figure 4-7. Photomosaic of Marker T in 2010 and digitization of this mosaic. ......................... 134

Figure 4-8. Photomosaic of Marker B in 2009 and digitization of this mosaic......................... 135

Figure 4-9. Photomosaic of Marker B in 2010 and digitization of this mosaic.......................... 136

Figure 4-10. Photomosaic of Marker D in 2009 and digitization of this mosaic........................ 137

Figure 4-11. Photomosaic of Marker D in 2010 and digitization of this mosaic........................ 137

Figure 4-12. Photomosaic of Marker J in 2009 and digitization of this mosaic......................... 138

Figure 4-13. Photomosaic of Marker J in 2010 and digitization of this mosaic......................... 139

Figure 4-14. Photomosaic of Marker L in 2009 and digitization of this mosaic. ....................... 140

Figure 4-15. Photomosaic of Marker L in 2010 and digitization of this mosaic. ....................... 140

Figure 4-16. Photomosaic of Marker Y in 2010 and digitization of this mosaic........................ 141

Figure 4-17. Photomosaic of Marker G in 2009 and digitization of this mosaic........................ 142

Figure 4-18. Photomosaic of Marker G in 2010 and digitization of this mosaic........................ 143

Figure 4-19. Photomosaic of Marker H1 in 2009 and digitization of this mosaic...................... 144

Figure 4-20. Photomosaic of Marker H1 in 2010 and digitization of this mosaic...................... 145

Figure 4-21. Photomosaic of Marker H2 in 2009 and digitization of this mosaic...................... 146

Figure 4-22. Photomosaic of Marker H2 in 2010 and digitization of this mosaic...................... 147

Figure 4-23. Photomosaic of Marker M in 2009 and digitization of this mosaic....................... 147

Figure 4-24. Photomosaic of Marker M in 2010 and digitization of this mosaic....................... 148

Figure 4-25. Photomosaic of Marker N in 2009 and digitization of this mosaic........................ 149

Figure 4-26. Photomosaic of Marker N in 2010 and digitization of this mosaic........................ 150

Figure 4-27. Photomosaic of Marker O in 2009 and digitization of this mosaic........................ 151

Figure 4-28. Photomosaic of Marker O in 2010 and digitization of this mosaic........................ 151

Figure 4-29. Photomosaic of Marker Q in 2009 and digitization of this mosaic........................ 152

Figure 4-30. Photomosaic of Marker Q in 2010 and digitization of this mosaic........................ 153

Figure 4-31. Photomosaic of Marker C in 2009 and digitization of this mosaic........................ 154

Figure 4-32. Photomosaic of Marker C in 2010 and digitization of this mosaic........................ 154

Figure 4-33. Photomosaic of Marker E in 2009 and digitization of this mosaic........................ 155

Figure 4-34. Photomosaic of Marker E in 2010 and digitization of this mosaic. ....................... 156

Figure 4-35. Photomosaic of Marker V in 2010 and digitization of this mosaic........................ 157

Figure 4-36. Photomosaic of Marker U in 2010 and digitization of this mosaic........................ 157
xix

Figure 4-37. Photomosaic of Marker A in 2009 and digitization of this mosaic........................ 158

Figure 4-38. Photomosaic of Markers T1/T2 in 2010 and digitization of this mosaic............... 159

Figure 4-39. Photomosaic of Marker X in 2010 and digitization of this mosaic........................ 159

Figure 4-40. Photomosaic of Marker AA in 2010 and with each coral located on the mosaic. . 160

Figure 4-41. Photomosaic of Marker 5 in 2009 and digitization of this mosaic. ....................... 161

Figure 4-42. Vertical Mosaic F.- J2-460 - GB535 - Heading 309 ̊ (8/28/09)............................. 162

Figure 4-43. Vertical Mosaic 39. ................................................................................................ 163

Figure 4-44. Vertical Mosaic T1-T2........................................................................................... 164

Figure 4-45. Vertical Mosaic X. ................................................................................................. 164

Figure 4-46. Hierarchical cluster dendrogram based on Bray-Curtis Index values of total 

faunal presence/absence showing the relationship between mosaic sites. If the 

site was imaged twice (in both 2009 and 2010), only the 2010 mosaic was used 

in this analysis. The mosaic sites are color-coded by lease block region. ........... 166

Figure 4-47. Hierarchical cluster dendrogram based on Bray-Curtis Index values of relative 

polygon coverage showing the relationship between mosaic sites. If the site 

was imaged twice (in both 2009 and 2010), only the 2010 mosaic was used in 

this analysis. The mosaic sites are color-coded by lease block region................. 166

Figure 4-48. Hierarchical cluster dendrogram based on Bray-Curtis Index values of solitary 

fauna density showing the relationship between mosaic sites. The mosaic sites 

are color-coded by lease block region.................................................................. 167

Figure 4-49. Hierarchical cluster dendrogram based on Bray-Curtis Index values of solitary 

fauna density showing the relationship between mosaic sites. If the site was 

imaged twice (in both 2009 and 2010), only the 2010 mosaic was used in this 

analysis. The mosaic sites are color-coded by the dominant coral present at that 

mosaic site. ........................................................................................................... 167

Figure 4-50. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of solitary fauna density. Each point represents a mosaic site colorcoded by lease block region. If the site was imaged twice (in both 2009 and 

2010), only the 2010 mosaic was used in this analysis. ....................................... 168

Figure 4-51. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of solitary fauna density. Each point represents a mosaic site colorcoded by the dominant coral present at that mosaic site. If the site was imaged 

twice (in both 2009 and 2010), only the 2010 mosaic was used in this analysis. 169

Figure 4-52. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of solitary fauna density. Each point represents a mosaic site colorcoded hotto cold by depth and labeled with the site depth in meters. If the site 

was imaged twice (in both 2009 and 2010), only the 2010 mosaic was used in 

this analysis. ......................................................................................................... 169

Figure 4-53. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of relative polygon coverage. Each point represents a mosaic site color-
xx

coded hot to cold by depth and labeled with the site depth in meters. If the site 

was imaged twice (in both 2009 and 2010), only the 2010 mosaic was used in 

this analysis. ......................................................................................................... 170

Figure 4-54. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of faunal presence/absence. Each point represents a mosaic site colorcoded hot to cold by depth and labeled with the site depth in meters. If the site 

was imaged twice (in both 2009 and 2010), only the 2010 mosaic was used in 

this analysis. ......................................................................................................... 170

Figure 4-55. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of solitary fauna density. Each point represents a mosaic site within the 

range of Lophelia pertusa (200-600 m) labeled by mosaic site. The points are 

color coded longitudinally east to west by a red to blue gradient. Mississippi 

Canyon locations are colored black with sites west of the Mississippi Canyon 

colored blue and those east colored red. The shapes of the points are grouped 

by lease block region. If the site was imaged twice (in both 2009 and 2010), 

only the 2010 mosaic was used in this analysis. .................................................. 171

Figure 4-56. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of faunal presence absence of mosaic sites within the depth range of 

Lophelia pertusa (200-600 m) labeled by mosaic site. The points are color 

coded longitudinally east to west by a red-to-blue gradient. Mississippi Canyon 

locations are colored black with sites west of the Mississippi Canyon colored 

blue and those east colored red. The shapes of the points are grouped by lease 

block region. If the site was imaged twice (in both 2009 and 2010), only the 

2010 mosaic was used in this analysis. ................................................................ 172

Figure 4-57. The top three graphs show the percent of the total population of the taxon (crabs, 

crinoids, brittle stars) that occurred on each substratum type at each site. 

Population size (n) at each site is shown over the columns. The bottom graph 

shows the percentage of each substratum type available at each site. ................. 174

Figure 4-58. The top three graphs show the percent of the total population of the taxon 

(urchins, whip corals) that occurred on each substratum type at each site. 

Population size (n) at each site is shown over the columns. The bottom graph 

shows the percentage of each substratum type available at each site. ................. 175

Figure 4-59. The top three graphs show the percent of the total population of the taxon 

(anemones) that occurred on each substratum type at each site. Population size 

(n) at each site is shown over the columns. The bottom graph shows the 

percentage of each substratum type available at each site. .................................. 176

Figure 4-60. The top three graphs show the percent of the total population of the taxon (crabs, 

fish) that occurred on each substratum type at each site. Population size (n) at 

each site is shown over the columns. The bottom graph shows the percentage of 

each substratum type available at each site. ......................................................... 177

Figure 4-61. The top three graphs show the percent of the total population of the taxon (crabs, 

sponges) that occurred on each substratum type at each site. Population size (n) 
xxi

at each site is shown over the columns. The bottom graph shows the percentage 

of each substratum type available at each site...................................................... 178

Figure 4-62. Hierarchical cluster dendrogram based on Bray-Curtis Index values of total 

faunal presence absence showing the relationship between the overlapping 

portions of mosaic sites imaged in both 2009 and 2010. The mosaic is colorcoded by site and the shapes are grouped by lease block region. ........................ 180

Figure 4-63. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of faunal presence absence showing the distance between the 

overlapping portions of mosaic sites imaged in both 2009 and 2010. Each point 

represents a mosaic color coded by site and grouped by shape according to 

lease block region................................................................................................. 180

Figure 4-64. Hierarchical cluster dendrogram based on Bray-Curtis Index values of relative 

polygon coverage showing the relationship between the overlapping portions of 

mosaic sites imaged in both 2009 and 2010. The mosaics are color-coded by 

site and the shapes are grouped by lease block region. ........................................ 181

Figure 4-65. Hierarchical cluster dendrogram based on Bray-Curtis Index values of solitary 

fauna density showing the relationship between the overlapping portions of 

mosaic sites imaged in both 2009 and 2010. The mosaics are color-coded by 

site and the shapes are grouped by lease block region. ........................................ 182

Figure 4-66. Diversity of coral communities collected during Lophelia I and II related to 

characteristics of the coral skeleton in the collections. Only significant 

regression relationships are shown....................................................................... 187

Figure 4-67. Multidimensional scaling ordination plot of community similarity (based on 

Bray-Curtis similarity), where collections that appear closer together have 

higher community similarity. ............................................................................... 188

Figure 4-68. Lophelia II coral associate sampling sites in the GoM. GB = Garden Banks, GC 

= Green Canyon, MC = Mississippi Canyon, VK = Vioska Knoll, and DC = 

DeSoto Canyon..................................................................................................... 190

Figure 4-69. Coral associate taxonomic composition by phyla over three Lophelia II cruises.. 194

Figure 4-70. Multidimensional scaling plot of coral associates located in the northeastern 

GoM (East, green triangles) and the northwestern GoM (West, blue triangles) 

using the Bray-Curtis similarity index. The distinction of east and west is 

delineated by the location of the entrance of the Mississippi River into the Gulf. 

Ordination points superimposed by geographic area. .......................................... 195

Figure 4-71. Multidimensional scaling plot of coral associates for 500 m depth bins using the 

Bray-Curtis similarity index. Ordination points superimposed by depth region: 

Green = 0-500 m, Cyan = 500-1,000 m, Red = 1000-1500 m, Blue > 1,500 m. . 196

Figure 4-72. Images of Asteroschema clavigerum from MC294. The top two images show 

the typical tan to red coloration and tightly-coiled arm posture observed in this 

species. The bottom two images show the white armed and completely 

bleached coloration as well as the splayed out arm posture................................. 196
xxii

Figure 4-73. Images of Asteroschema clavigerum from MC294. The top two images show 

the typical tan to red coloration and tightly-coiled arm posture observed in this 

species. The bottom two images show the white armed and completely 

bleached coloration as well. ................................................................................. 197

Figure 5-1. Sites where octocorals (soft corals, stoloniferan corals, and gorgonians) were 

collected during surveys....................................................................................... 203

Figure 5-2. Species-accumulation curve (dotted line) and 95% confidence intervals (solid 

lines). .................................................................................................................... 206

Figure 5-3. New species of scleraxonian growing on the Gulf Penn wreck.............................. 207

Figure 5-4. Photo of Anthothela nov. sp. 1 at GB535. .............................................................. 208

Figure 5-5. Photo of Aquaumbridae from the W FL Slope. ...................................................... 208

Figure 5-6. Unidentified stoloniferan growing on a glass sponge. ............................................ 209

Figure 5-7. Phylogenetic inference of the extended barcode (COI+igr1+MutS) of GoM deepwater octocorals. Consensus tree based on Bayesian analysis with posterior 

probabilities (above nodes) and bootstrap values (below nodes) indicated on 

tree. Posterior probabilities are >90% (*) unless indicated. Tree was rooted at 

the midpoint.......................................................................................................... 210

Figure 5-8. Species richness by average site depth.................................................................... 212

Figure 5-9. MDS plot with distance between points representing Sorensen’s Index of 

Similarity. Assemblage similarity at > 20 (dotted line) and 35% (solid line) are 

indicated. Circle size denotes average site depth. Stress=0.06. ........................... 214

Figure 5-10. . MDS plot with distance between points representing Sorensen’s Index of 

Phylogenetic Similarity (mean branch length substituted for species in 

Sorensen’s Index). Assemblage similarity at > 20 (dotted line) and 35% (solid 

line) are indicated. Circle size denotes average site depth. .................................. 215

Figure 5-11. Neighbor-joining tree of mtMutS haplotypes sequenced from collections off 

Cape Canaveral, FL (in bold) and genetically-similar haplotypes sequenced 

from the Gulf. ....................................................................................................... 217

Figure 5-12. Morphology of GoM Callogorgia spp. Scanning electron microscopy images of 

polyps and whole colony images for (A-C) Callogorgia gracilis, (D-F) C. a. 

americana, and (G-I) C. a. delta. 500 um scale bar indicated. ............................. 221

Figure 5-13. Maximum clade credibility tree of Callogorgia at combined loci 

(cox1+mtMutS+28S) Posterior probabilities were all >90%. Numbers 

designate genbank sequences. .............................................................................. 223

Figure 5-14. Scanning electron microscopy of sclerite composition and structure of six 

haplotypes of Paramuricea with photos of colony morphology. Scale bar 

indicates 500 um................................................................................................... 224

Figure 5-15. Median joining network of haplotypes collected in the GoM. Size of circle 

corresponds to total number collected. Number of substitutions is indicated by 

slash marks (except Type 1 to the remaining is indicated by a number 35). ....... 225
xxiii

Figure 5-16. Principal coordinate analysis of Callogorgia americana americana (orange 

diamonds) and Callogorgia americana delta (blue squares). .............................. 228

Figure 5-17. Principal coordinate analysis based on genotypic distances of Callogorgia 

americana delta across seven sites. Sites are color coded by mean depth (blue< 

600 m, purple > 600 m)........................................................................................ 229

Figure 5-18. Pairwise genetic differentiation patterns with respect to a) depth and b) 

geographic distance in Callogorgia americana delta. Large, dark blue circles 

indicate depth differences of >200 m between sites............................................. 230

Figure 5-19. Sampling sites for Leiopathes glabberima (inset) in the GoM. GB = Garden 

Banks, GC = Green Canyon, VK = Vioska Knoll, WFS = West Florida Slope. 

GB and GC are in biogeographic region I, VK is in biogeographic region II and 

WFS is within biogeographic region III (Cairns and Opresko 1993). Map from 

Google Earth......................................................................................................... 232

Figure 5-20. Bayesian phylogenies of two mitochondrial markers COI (A, 740bp; GenBank 

Accession numbers: KF013048 - KF013088) and ND5 (B, 660 bp, GenBank 

Accession numbers: KF012993 - KF013047). There was very little sequences 

diversity in L. glaberrima samples from throughout the GoM resulting in starshaped phylogenies............................................................................................... 236

Figure 5-21. Phylogeny (Bayesian Inference) of a portion of the mitochondrial TRP gene 

(730 bp GenBank Accession numbers: KF013089 - KF013130). Two lineages 

within L. glaberrima from the GoM are revealed by the TRP gene, distinct by 

one amino acid change. Numbers represent posterior probabilities. Note that 

the two lineages are unrelated to color of the colonies (Red labels indicate red 

colonies, orange labels orange colonies, blue labels white colonies and black 

labels are colonies with no associated color information), sampling site 

(VK906, VK826) or microsatellite lineage designation (see next section).......... 238

Figure 5-22. Mean F values for microsatellite loci. Mean F values were not significantly 

different from zero for most loci (BC 1 – BC 67) in lineage 1 (L1) but in 

lineage 2 (L2), F-values consistently deviated from expectations. Given are 

means across loci and their standard errors.......................................................... 239

Figure 5-23. Population genetic analysis of 148 L. glaberrima genotypes from the GoM. The 

STRUCTURE plot shows the probability of membership of each of the 

samples in K=2 clusters (the optimal number of clusters for this dataset). 

VK826 harbors colonies with ancestry in both lineages (hybrids). VK862 

excluded (n=2)...................................................................................................... 239

Figure 5-24. Principal coordinates analysis of 148 L. glaberrima genotypes from the GoM. 

For comparison with Fig 3, the two lineages identified via STRUCTURE 

analysis are indicated here by the blue and red circle. Shown are the first two 

axes, explaining 46.05% and 13.27% of the variation, respectively. VK862 

excluded (n=2)...................................................................................................... 240

Figure 5-25. Principal coordinates analysis of 148 L. glaberrima genotypes from the GoM. 

No structuring by color of the colony (A) or by depth (B) is evident. Shown are 

the first two axes, explaining 46% and 13% of the variation, respectively. 
xxiv

Depth is in 50 m increments. Samples sizes per depth given in parentheses. uk 

= color unknown................................................................................................... 241

Figure 5-26. Geographical distribution of Leiopathes glaberrima lineages. Vioska Knoll 826 

(A) harbors two lineages of L glaberrima (Msat Lineage 1, 2). Lineage 1 is 

mostly restricted to the northern edge of the site. Lineage 2 and hybrids 

between lineages 1 and 2 (designated as Lineage 3) occur throughout the site. 

Permanent markers (Mosaic N – Q) are indicated. Vioska Knoll 906 (B) 

harbors only one lineage of L. glaberrima (Msat 2). Two meter contours 

created by Miles Saunders from R/V Falkor Shipboard Multibeam 11/2012. 

Maps oriented towards North............................................................................... 242

Figure 5-27. Geographic distribution of clone mates of Leiopathes glaberrima at VK826 and 

VK906. Msat lineage 2 of Leiopathes glaberrima frequently reproduces 

asexually at Vioska Knoll 826 (A) and VK906 (B) while lineage 1 does so 

rarely. Same fill indicates that two colonies are clonemates. Black fill indicates 

colonies with unique genotype, represented only once at the site. No clones 

were shared between sites. Two meter contours created by Miles Saunders 

from R/V Falkor Shipboard Multibeam 11/2012. Map oriented towards North. 242

Figure 5-28. Geographic distribution of Leiopathes glaberrima color morphs in VK826 and 

VK906. A) VK826, B) VK906. Two meter contours created by Miles Saunders 

from R/V Falkor Shipboard Multibeam 11/2012. Map oriented towards North. 243

Figure 6-1. Callogorgia americana and commensal ophiuroids............................................... 247

Figure 6-2. δ15N vs. 

13C for all soft corals sampled for stable isotope analysis. ..................... 251

Figure 6-3. δ15N vs. δ13C of (A) Calligorgia americana delta, (B) Callogorgia americana 

americana, (C) Paramuricea sp. E, and (D) Leiopathes sp., with difference 

symbols representing different sampling sites. .................................................... 252

Figure 6-4. (A) δ13C of epizoic ophiuroids vs. δ13C of their host corals. (B) δ15N of epizoic 

ophiuroids vs. δ15N of their host corals. The solid line in (A) represents a 

simple linear regression and the broken line in both panels represents equal 

values on the x- and y-axes. ................................................................................. 254

Figure 6-5. (A) δ13C of associated ophiuroid vs. δ13C of Callogorgia americana americana, 

(B) δ15N of associated ophiuroid vs. δ15N of Callogorgia americana 

americana, (C) δ13C of associated ophiuroid vs. δ13C of Callogorgia americana 

delta, (D) δ15N of associated ophiuroid vs. δ15N of Callgorgia americana 

delta...................................................................................................................... 255

Figure 6-6. (A) δ15N vs. δ13C of Lophelia pertusa and associated macrofauna from 

quantitative coral pot collections from MC751 (dive J2-436) and (B) GB535 

(dive J2-531)......................................................................................................... 256

Figure 6-7. Small tube worm aggregations interspersed with colonies of Callogorgia 

americana delta at MC885................................................................................... 257

Figure 6-8. Lophelia pertusa growing on vestimentiferan tube worms with Acesta sp at 

MC751.................................................................................................................. 259
xxv

Figure 7-1. Representative example of maintenance aquarium setup. The upper aquarium is 

the display tank and held the corals and associates. Below the aquarium is the 

sump tank and requisite filtration compartments. ................................................ 263

Figure 7-2. Actual and target values of total alkalinity in carbonate chemistry manipulations. 

Error bars represent standard deviation of mean actual (observed) total 

alkalinity............................................................................................................... 267

Figure 7-3. Actual and target values of pH in carbonate chemistry manipulations. Error bars 

represent standard deviation of mean actual (observed) pH values. .................... 268

Figure 7-4. Actual and target values of dissolved oxygen in oxygen manipulations. Error bars 

represent standard deviation of mean actual (observed) dissolved oxygen 

values.................................................................................................................... 268

Figure 7-5. Example of consecutive time-lapse photographs showing movement of Lophelia 

pertusa fragment, likely caused by the activity of Eunice sp. inhabiting a small 

PVC coral mount. Also shown is the typical position of the Coralliophila sp. 

gastropod on the Lophelia fragment..................................................................... 271

Figure 7-6. Experimental aquarium (20 gallons) with pH controller setup............................... 272

Figure 7-7. Lophelia pertusa attached to 1” PVC male adapter pieces in the maintenance 

aquarium............................................................................................................... 273

Figure 7-8. pH conditions (mean ± S.D.) for groups 1 and 2 for the pH experiments. ............. 276

Figure 7-9. Ωarag conditions (mean ± S.D.) for groups 1 and 2 for the pH experiments. ........ 277

Figure 7-10. Growth of L. pertusa (over 7 days, mean ± S.E.) from the group 1 pH 

experiments. ......................................................................................................... 278

Figure 7-11. Growth of L. pertusa (over 7 days, mean ± S.E.) from the group 2 pH 

experiments. ......................................................................................................... 278

Figure 7-12. Growth of L. pertusa (over 7 days, mean ± S.E.) from both groups 1 and 2 for 

the pH experiment. ............................................................................................... 279

Figure 7-13. Linear regression of L. pertusa growth to measured pH (over 7 days, mean ± 

S.E.) from both groups 1 and 2 for the pH experiment. ....................................... 280

Figure 7-14. Linear regression of L. pertusa growth to measured aragonite saturation states 

(over 7 days, mean ± S.E.) from both groups 1 and 2 for the pH experiment. .... 280

Figure 7-15. Temperature conditions (mean ± s.d.) for the temperature experiments. ............. 283

Figure 7-16. pH conditions (mean ± s.d.) for the temperature experiments.............................. 284

Figure 7-17. Ωarag conditions (mean ± s.d.) for the temperature experiments......................... 284

Figure 7-18. Cumulative survivorship of L. pertusa (over 7 days, mean ± S.E.) from the 

temperature experiments. ..................................................................................... 285

Figure 7-19. Growth of L. pertusa (over 7 days, mean ± S.E.) from the temperature 

experiment. ........................................................................................................... 286
xxvi

Figure 7-20. Dissolved oxygen conditions (mean ± S.D.) for the dissolved oxygen 

experiments. ......................................................................................................... 287

Figure 7-21. Percent survivorship of L. pertusa (over 7 days, mean ± S.E.) from the 

dissolved oxygen experiments.............................................................................. 288

Figure 7-22. Ωarag conditions (mean ± S.D.) for the dissolved oxygen experiments................. 289

Figure 8-1. An apparent colonial coral that is not L. pertusa is visible on the left edge of this 

structural member on Pompano at 336 m depth. Four “corals” resembling this 

were seen at Pompano. ......................................................................................... 293

Figure 8-2. White globular coral or sponge from Pompano 5/24/2011 survey at a depth of 

180 m (590 ft)....................................................................................................... 293

Figure 8-3. Small school of amberjacks, Seriola dumerili, seen on the 2011 survey of 

Pompano at 178 m depth. ..................................................................................... 294

Figure 8-4. School of jacks (species level ID not possible from image) imaged at 37 m depth 

on platform Jolliet. ............................................................................................... 296

Figure 8-5. School of chub, Kyphosus sectatrix, at 38 m depth on platform Jolliet.................. 297

Figure 8-6. L. pertusa on the sea floor under Platform Ram Powell at a depth of 1,010 m...... 298

Figure 8-7. L. pertusa colonies growing on the sea floor near the base of Platform Cognac at 

depth of 322 m...................................................................................................... 299

Figure 8-8. Close-up of what appears to be a non-L. pertusa colonial coral on Platform 

Cognac at a depth 234 m. ..................................................................................... 300

Figure 8-9. Numerous “non-L. pertusa colonial corals” on Platform Cognac at a depth of 328 

m........................................................................................................................... 300

Figure 8-10. Flow-tube connection at Zinc installation with broken L. pertusa approximately 

7 m above the sea floor......................................................................................... 301

Figure 8-11. Fauna incrusted flow-tube connection about 7 m above the sea floor at the Zinc 

installation. ........................................................................................................... 302

Figure 8-12. Light cnidarian encrustation with no L. pertusa on base of the abandoned test 

pile near the Zinc installation (within 5 m of the sea floor). ................................ 302

Figure 8-13. Atlantic roughy, Hoplostethus occidentalis, among L. pertusa around the 

abandoned test-pile near the Zinc installation at 450 m depth. ............................ 303

Figure 8-14. Location of platforms, shipwrecks, and sub-sea installation by lease block. ....... 307

Figure 8-15. Diagram of the measuring protocol for L. pertusa colonies. For the 

determination of growth rates, maximum extension from an attachment point, 

such as shown for colony “a”, is used. The dashed line is used to establish a 

point of colony contact with the structure. The light line (df) represents the 

distance used to estimate minimum linear colony growth rates. The dark line 

(d1) represents the measurement of colony diameter, which, in conjunction with 

the linear extension measurement, is used to calculate minimum colony area for 

corals captured in profile. To determine colony area for corals on the surface of 
xxvii

the structures, two diameters are measured (see coral “b”); one at the widest 

point of the colony (dark line, d1) and another perpendicular to the other, mid 

point on line d1 (light line, d2). The two lasers in the image are 10 cm apart and 

used for scale. ....................................................................................................... 309

Figure 8-16. Example of screen shot used for percent coverage analysis. Structure G at 304 

m with 57% of the structure covered with L. pertusa. The structure is outlined 

in red and the L. pertusa covering the platform surface are outlined in black..... 310

Figure 8-17. Colony density vs. depth Scatter plot of colony density vs. depth. Petronius=A, 

Pompano=B, Ram Powell=C, Neptune=D, Jolliet=E, Zinc=F. Cognac was not 

included in this analysis because portions of the structure were covered in 

“thickets” of L. pertusa and thus colony density could not be determined. 

1Measurements only obtained to 437 m. Structure depth is 524 m.2 Solid or 

compliant type structures. The other platforms are spar or tension leg type 

structures. ............................................................................................................. 311

Figure 8-18. Mosaic of L. pertusa thickets growing on the bow of the Gulfoil shipwreck....... 312

Figure 8-19. Scatter plots of colony area (size) vs. depth. Petronius=A, Pompano=B, Ram 

Powell=C, Neptune=D, Jolliet=E. Only Ram Powell is in a water depth that 

exceeds the known depth range of L. pertusa. Colony measurements are biased 

against smaller colonies that may not have shown up on poorer quality video 

and against very large colonies at high densities where individual colonies were 

difficult to distinguish from one another.............................................................. 313

Figure 8-20. Relationship between highest growth rate and density on different depth 

segments of Ram Powell. The highest growth rate measured in a 12.25 m (50 

ft) section of the structure plotted against the density of colonies in that section. 

Ram Powell was used for this analysis because it is the only platform in our 

data set that spans the entire depth range of L. pertusa. The regression equation 

for this data set is. y = 0.088 +0.79. R2adj.= 52.2%, p-value < 0.0001.............. 314

Figure 8-21. Example images of structure bases showing absence of L. pertusa below 5-10 m 

above the sea floor. Approximately 2.5-3 m of structure are visible in each 

image. a) leg of Petronius; b) leg of Pompano; c) riser connection on Neptune; 

d) abandoned flow tube connection at Zinc showing the beginning of L. pertusa

colonization approximately 8 m off the sea floor................................................. 315

Figure 8-22. Colored L. pertusa colonies - a) An orange L. pertusa colony at ~300 m on 

Jolliet. b) A colony of mixed colored L. pertusa at ~400 m on Jolliet................. 316

Figure 8-23. Minimum growth rate vs. age of structure (maximum possible age of coral 

colony). There was no significant relation between growth rate and age of the 

structure within any subgroup and the line shown is for all structures (R2 sdj = 

54.8, p = 0.009). See Table 8-2for regression statistics. ...................................... 317

Figure 9-1. The inset in this figure illustrates the location of VK906 on the background of 

computer-shaded multibeam bathymetry of the OCS and upper continental 

slope. The mound identified on this map was cored at the crest and flank. 

Note that the water depth of the mound crest is less than 400 m (1,312 ft.) and 
xxviii

the base is between 420 m (1,378 ft.) and 430 m (1,410 ft.). Core locations are 

shown at the mound crest, mound, flank, and an intermound site. ...................... 321

Figure 9-2. (A) This combined 3-D seismic sea floor acoustic amplitude and bathymetry map 

generally defines a shallow subsurface and tabular salt body with a gully-like 

sea floor depression along its western and southern flanks. Note that the 

scattered patterns of high surface amplitude generally occur around the flanks 

of the salt body, but high amplitudes are not exclusive to the flanks. The 

bathymetry defines several mounds above the salt body. Seismic line a-a ́ cuts 

through three of these mounds near the southern end of the salt body and is the 

location of the profile illustrated below. The inset is the aft deck of the R/V

Brooks McCall on site to collect a Jumbo Piston Core from the largest Lophelia

mound shown on the seismic profile below. (B) This seismic profile is oriented 

roughly N-S across the shallow tabular salt body over which small mounded 

features occur on the sea floor. The inset is a high resolution bathymetric 

image of the largest Lophelia mound located at the southern edge of the salt 

body. This multibeam bathymetry image was acquired by the ROV Jason II. 

The “roughness” at the mound crest and upper flanks is a reflection of living 

Lophelia thickets currently growing on the mound surface. ................................ 323

Figure 9-3. (A) A living Lophelia “thicket” on top of a small mounded structure near the 

crest of the Lophelia mound of Figure 9-2B. (B) Living Lophelia and coral 

rubble on the surface of the largest mound seismically imaged in Figure 9-2B. . 324

Figure 9-4. Multisensor core logger profiles of Gamma Density, Magnetic Susceptibility, 

and Resistivity for the Mound Crest 2 JPC. ......................................................... 327

Figure 9-5. Multisensor core logger profiles of Gamma Density, Magnetic Susceptibility, 

and Resistivity for the Mound Flank JPC. ........................................................... 328

Figure 9-6. Multisensor core logger profiles of Gamma Density, Magnetic Susceptibility, 

and Resistivity as well as an example X-ray radiograph for the Intermound 

Standard Piston Core. Note the subtle clay-to-silty clay layering revealed in 

the X-ray radiograph. ........................................................................................... 329

Figure 9-7. This high resolution digital image of the Mound Crest 2 JPC illustrates that 

corals occur throughout the mound which was sampled to a depth below the 

mound surface of ~ 16 m (53 ft.). The JPC was cut into eleven sections, as 

shown in this photograph. .................................................................................... 333

Figure 9-8. This photograph is a close-up of the middle of Section 4 of the Mound Crest 2 

JPC illustrated in the previous figure. Note the densely packed coral “sticks” 

and smaller fragments. The matrix sediment is rich in clay minerals and 

calcareous microfossil tests. The width of the core photograph is ~ 12 cm (5 

in).......................................................................................................................... 334

Figure 9-9. X-ray diffraction data (0-36° 2ө) of the matrix sediment (depth of 15 m below 

the sea floor in the Mound Crest 2 core) illustrating the presence of smectite, 

chlorite, illite, and kaolinite on heated, glycolated, and air-dried scans. Quartz 

and calcite (microfossil tests) are also present, but mostly in the silt and fine 

sand fraction. ........................................................................................................ 337
xxix

Figure 9-10. (A) Clay minerals in the Mound Crest 2 core matrix sediment at the 0.5 m (1.6 

ft.) level. (B) Clay minerals in the Mound Crest 2 core matrix sediment at the 

10.5 m (34.4 ft.) level. .......................................................................................... 338

Figure 9-11. A stratigraphic chart for the GoM showing the oxygen isotope stages, 

biostratigraphic zones and subzones, and tephra (after Kohl et al., 2004). All 

dates are in conventional years BP....................................................................... 339

Figure 9-12. A depositional rate curve for the Mound Crest 2 core (MC-2), Viosca Knoll 

Block 906. The graph illustrates two unconformities encountered in the core. 

The first is at the sea floor with an age of 40 ka BP, based on a 14C date from a 

Lophelia pertusa coral sampled from top of core. The second unconformity is 

based on foraminiferal biostratigraphic datums and represents 24 ka of missing

section. The left hand column shows the boundaries of the foraminiferal 

Ericson zones interpreted by Kennett et al. (1972). A projection based on the 

sedimentation rate shows that approximately six m of core may be missing 

from the top. The X/W boundary was reached at 16 meters below sea floor. 

All dates are in conventional years BP................................................................. 340

Figure 9-13. Skeletal density of Lophelia pertusa samples from the Mound Crest 2 core. ...... 342

Figure 10-1. Overview map with locations of shipwrecks examined in this study. .................. 345

Figure 10-2. North-central Gulf Coast in 1806.......................................................................... 347

Figure 10-3. Illustration depicting New York Harbor quarantine of immigrant vessels 

(Graetz, 1883)....................................................................................................... 348

Figure 10-4. Typical nineteenth-century brig (U.S. Dept. of the Treasury, Bureau of 

Statistics 1886). .................................................................................................... 351

Figure 10-5. Clipper ship Young American (Clark 1910)......................................................... 351

Figure 10-6. An example of double-framed construction illustrating ship construction 

terminologies used in this report. ......................................................................... 358

Figure 10-7. Side scan sonar image of the VK Wreck and surrounding area (courtesy of C & 

C Technologies, Inc.). .......................................................................................... 360

Figure 10-8. Side scan sonar image, close-up of the VK Wreck (courtesy of C & C 

Technologies, Inc.). .............................................................................................. 361

Figure 10-9. North-up plan view of the VK Wreck. Processed multibeam image at 1.5-foot 

bin size (Courtesy of C & C Technologies, Inc.). ................................................ 362

Figure 10-10. A 3-D perspective view of the VK Wreck. Processed multibeam image at 1.5-

foot bin size (courtesy of C & C Technologies, Inc.)........................................... 362

Figure 10-11. Viosca Knoll Wreck Site Drawing based on ROV investigation findings.......... 365

Figure 10-12. Front view of stem post showing list to starboard. ............................................. 366

Figure 10-13. Sheathing detail from starboard side................................................................... 367

Figure 10-14. Diagonal foiling observed in sheathing (Starboard side).................................... 367

Figure 10-15. Mosaic of the bow (view from port side)............................................................ 368
xxx

Figure 10-16. Close up profile of upper stem remains. ............................................................. 369

Figure 10-17. Gammon irons and head rigging. ........................................................................ 369

Figure 10-18. Image of net remnants on the seafloor near the Viosca Knoll Wreck’s bow. ..... 370

Figure 10-19. Image of the Viosca Knoll Wreck showing the tear in the port hull. .................. 371

Figure 10-20. Copper-sheathed rudder of the VK Wreck with close-up inset showing a 

portion of the pintle (10 cm laser scale shown at bottom of inset). ..................... 372

Figure 10-21. Possible Gudgeon strap lying on the seafloor at the stern of the VK Wreck...... 372

Figure 10-22. Starboard side view of the VK Wreck’s stern showing possible gaff head-ring, 

ingots, water filter on the right side of the image, and rudder in the background.373

Figure 10-23. Water filter and replacement charcoal. ............................................................... 374

Figure 10-24. Ceramic disk, which is likely part of the water filter.......................................... 374

Figure 10-25. Mosaic of the VKE Wreck’s foremast rigging, showing mast cap, chain plate, 

and possible masthead block. ............................................................................... 376

Figure 10-26. VK Wreck’s deck structure from starboard view showing deck beams and 

lodging knees........................................................................................................ 377

Figure 10-27. Deck structure detail in plan view (drawing by Robert A. Church). .................. 378

Figure 10-28. Rigging away from VK Wreck’s main hull and possible ceramic cup or 

insulator located near mast cap. ........................................................................... 379

Figure 10-29. Patent stove found away from main hull............................................................. 380

Figure 10-30. Lantern away from main hull at VK Wreck site (2006 image, MMS 2008-

018)....................................................................................................................... 380

Figure 10-31. Unidentified object away from main hull at VK Wreck site (2006 image, 

MMS 2008-018)................................................................................................... 381

Figure 10-32. VK Wreck’s Water filter after conservation. ...................................................... 382

Figure 10-33. An 1882 advertisement in Export Merchant Shippers showing a Jowett & Co. 

Water Filter........................................................................................................... 383

Figure 10-34. Muntz Metal Sheathing from the Viosca Knoll Wreck. ..................................... 384

Figure 10-35. WW-GUCCI Microbial Test Platform being deployed near the port stern. ....... 385

Figure 10-36. Multibeam backscatter mosaic image of 7,000 Foot Wreck from data collected 

by the ABE Sentry AUV (Woods Hole Oceanographic Institution).................... 386

Figure 10-37. Photomosaic of the 7,000 Foot Wreck comprised of images taken from the 

ABE Sentry AUV (Image Woods Hole Oceanographic Institution).................... 387

Figure 10-38. Site map of the 7,000 FT Wreck based on ROV investigations. ........................ 389

Figure 10-39. Color photomosaic showing the 7,000 Foot Wreck site layout (Image Woods 

Hole Oceanographic Institution). ......................................................................... 390
xxxi

Figure 10-40. American schooner Lettie G. Howard was built at Essex, Massachusetts in 

1893 (Image from South Street Seaport Museum, New York)............................ 391

Figure 10-41. Stem post remains on the 7,000 Foot Wreck. ..................................................... 392

Figure 10-42. Image showing the over-turned windlass in bow of 7,000 Foot Wreck. ............ 393

Figure 10-43. Overhead view of the over-turned windlass on 7,000 Foot Wreck, bow is 

toward upper left corner of image. ....................................................................... 393

Figure 10-44. Windlass on 7,000 Foot Wreck with individual components identified............. 394

Figure 10-45. Wire Rope Lays (Wire Rope and Fiber Rigging Navy Ships’ Technical 

Manuel Chapter 613)............................................................................................ 395

Figure 10-46. Remnants of foremast rigging and mast cap from the 7,000 Foot Wreck. ......... 396

Figure 10-47. Close-up view of foremast rigging and possible mast cap from the 7,000 Foot 

Wreck. .................................................................................................................. 396

Figure 10-48. Miscellaneous rigging in the bow of the 7,000 Foot Wreck. .............................. 397

Figure 10-49. Mainmast rigging and components on the 7,000 Foot Wreck. ........................... 398

Figure 10-50. Mast band and yoke in the interior of the 7,000 Foot Wreck. ............................ 398

Figure 10-51. Copper sheathing with sheathing nails intact near bow of 7,000 Foot Wreck.... 399

Figure 10-52. Close-up of a section of sheathing with sheathing nails intact in the 7,000 Foot 

Wreck. .................................................................................................................. 400

Figure 10-53. Anchor at starboard bow of 7,000 Foot Wreck................................................... 401

Figure 10-54. Anchor at port bow of 7,000 Foot Wreck. .......................................................... 401

Figure 10-55. Auxiliary anchor amidships on the 7,000 Foot Wreck (view to starboard). ....... 402

Figure 10-56. Auxiliary anchor amidships on the 7,000 Foot Wreck (view to starboard). ....... 403

Figure 10-57. Image showing standard measurement points for anchor documentation. ......... 403

Figure 10-58. The 7,000 Foot Wreck’s helm, showing the wheel, exposed wheel-box, and 

rudder case............................................................................................................ 405

Figure 10-59. Steering gear housing European type, late 19th century (Mondfeld). ................ 406

Figure 10-60. Steering gear housing American type, late 19th century (Mondfeld)................. 406

Figure 10-61. Ship's wheel similar to that on the 7,000 Foot Wreck (Drawing by Daniel 

Warren, Image modified from Chapelle, Fishing Schooners).............................. 406

Figure 10-62. Image from the 7,000 Foot Wreck showing a possible galley stove (center) and 

a possible water barrels (center left and bottom left). .......................................... 407

Figure 10-63. A bottle (A) and Jug (B) in the forward area of the 7,000 Foot Wreck. ............. 408

Figure 10-64. Image of a lantern resting on top of the ship's stove in the forward area of the 

7,000 Foot Wreck. ................................................................................................ 409

Figure 10-65. The 7,000 Foot Wreck's compass being recovered during the 2009 site 

investigation. ........................................................................................................ 410
xxxii

Figure 10-66. The 7,000 Foot Wreck's compass following conservation. ................................ 411

Figure 10-67. Serial numbers located on the outer edge of the 7,000 Foot Wreck's compass. . 412

Figure 10-68. Cuprous metal sheathing and wood recovered from the 7,000 Foot Wreck....... 413

Figure 10-69. Wood Sample from 7,000 Foot Wreck. .............................................................. 414

Figure 10-70. A 2006 210p- kHz side scan sonar image of the Ewing Bank Wreck (ATP Oil 

and Gas)................................................................................................................ 417

Figure 10-71. A 410-kHz side scan sonar image of the Ewing Bank Wreck (C & C 

Technologies, Inc.)............................................................................................... 418

Figure 10-72. The 2008 field drawing of the Ewing Bank Wreck (Anne Corscadden Knox 

and PAST Foundation)......................................................................................... 420

Figure 10-73. Multibeam bathymetry image of the Ewing Bank Wreck (C & C Technologies, 

Inc.)....................................................................................................................... 422

Figure 10-74. Site map of the Ewing Bank Wreck based on ROV investigations..................... 423

Figure 10-75. Photomosaic of the Ewing Bank Wreck showing the three main areas of the 

wreck site: Area 1 (red outline) is the main hull; Area 2 (black outline) is the 

port debris zone; and Area 3 (blue outline) is the stern debris area (Image C &C 

Technologies, Inc.)............................................................................................... 424

Figure 10-76. View of bow and stempost of Ewing Bank Wreck (Aquapix Camera Image, 

Lophelia II, 2009: Deepwater Coral Expedition: Rigs, Reefs, and Wrecks). ...... 426

Figure 10-77. ROV video image capture of exposed hull remains at the Ewing Bank Wreck’s 

starboard bow. ...................................................................................................... 426

Figure 10-78. AUV Camera photograph showing a portion of the Ewing Bank Wreck's 

ballast pile. (C & C Technologies, Inc.)............................................................... 427

Figure 10-79. AUV camera photograph showing portions of the exterior port debris zone and 

the Ewing Bank Wreck's interior hull (C & C Technologies, Inc.). ..................... 428

Figure 10-80. AUV camera photograph of the stern and stern debris area of the Ewing Bank

Wreck (C & C Technologies, Inc.)....................................................................... 428

Figure 10-81. ROV video capture image looking north towards stern and stern debris area of 

the Ewing Bank Wreck ......................................................................................... 429

Figure 10-82. ROV video capture image of the Ewing Bank Wreck’s stempost (port view) 

with major components identified........................................................................ 430

Figure 10-83. Photograph of copper sheathing on the Ewing Bank Wreck’s stempost 

(Aquapix Camera Image, Lophelia II, 2009: Deepwater Coral Expedition: Rigs, 

Reefs, and Wrecks)............................................................................................... 430

Figure 10-84. AUV camera photograph of the Ewing Bank Wreck’s bow interior showing 

cant frames (C & C Technologies, Inc.)............................................................... 432

Figure 10-85. ROV video capture image showing the Ewing Bank Wreck's outer hull 

planking, hull framing, and interior ceiling planking........................................... 432
xxxiii

Figure 10-86. ROV video capture image showing ceiling planking on the Ewing Bank

Wreck’s starboard stern........................................................................................ 433

Figure 10-87. ROV video capture image of caulking remnants outlining disintegrated ceiling 

planking in the Ewing Bank Wreck’s starboard stern. ......................................... 434

Figure 10-88. Photograph showing details of the Ewing Bank Wreck’s stern (Aquapix 

Camera Image, Lophelia II, 2009: Deepwater Coral Expedition: Rigs, Reefs, 

and Wrecks).......................................................................................................... 435

Figure 10-89. ROV video capture image of in situ sheathing nails on the Ewing Bank

Wreck’s starboard hull sheathing. ........................................................................ 436

Figure 10-90. Photograph of sheathing nail from the Ewing Bank Wreck (University of West 

Florida). ................................................................................................................ 436

Figure 10-91. ROV video capture image of a Type 1 fastener on the Ewing Bank Wreck....... 437

Figure 10-92. ROV video capture image of a Type 2 fastener on Ewing Bank Wreck............. 438

Figure 10-93. ROV video capture image of a Type 3 fastener on the Ewing Bank Wreck....... 438

Figure 10-94. ROV video capture image of a Type 4 fastener on the Ewing Bank Wreck....... 439

Figure 10-95. ROV video capture image of a Type 5 fastener on the Ewing Bank Wreck....... 439

Figure 10-96. ROV video capture image showing Muntz metal copper sheathing and 

possible repair areas on the Ewing Bank Wreck’s starboard hull. ....................... 440

Figure 10-97. ROV video capture showing diagonal foiling of sheathing on the Ewing Bank

Wreck’s starboard stern........................................................................................ 441

Figure 10-98. AUV photograph of the Ewing Bank Wreck’s stone ballast partially covered in 

silt (C & C Technologies, Inc.). ........................................................................... 442

Figure 10-99. ROV video capture image of pipe remnant in Ewing Bank Wrecks interior hull 

(view to port). ....................................................................................................... 443

Figure 10-100. AUV camera photograph off pipe remnant, ballast, and 2009 microbiological 

experiment in the Ewing Bank Wreck’s interior aft hull (Image C & C 

Technologies, Inc.). .............................................................................................. 443

Figure 10-101. AUV camera photograph of pipe remnant in the Ewing Bank Wreck’s 

forward hull (Image C & C Technologies, Inc.). ................................................. 444

Figure 10-102. AUV camera photograph of ladder-like object in the Ewing Bank Wreck's 

interior hull (C & C Technologies, Inc.). ............................................................. 445

Figure 10-103. ROV video capture image of flange assemblies and pipe remnants on the 

Ewing Bank Wreck's port stern. ........................................................................... 446

Figure 10-104. ROV video capture image of ceramic concentration at the Ewing Bank

Wreck’s port stern. ............................................................................................... 447

Figure 10-105. ROV video capture image of ceramic container and flow blue decorated plate 

fragmenton the Ewing Bank Wreck...................................................................... 447
xxxiv

Figure 10-106. Photograph and drawing of ceramic piece recovered from the Ewing Bank

Wreck showing cameo design on lug handle (University of West Florida). ....... 448

Figure 10-107. A J & G Meakin "Pharaoh" cameo decorated sugar bowl (Image courtesy of 

the White Ironstone Society)................................................................................ 449

Figure 10-108. Photograph of ballast stone recovered from Ewing Bank Wreck (University 

of West Florida).................................................................................................... 450

Figure 10-109. Photograph showing crystalline structure on interior of ballast stone from the 

Ewing Bank Wreck............................................................................................... 450

Figure 10-110. Photograph of net in Ewing Bank Wreck's stern debris zone (Aquapix 

Camera Image, Lophelia II, 2009: Deepwater Coral Expedition: Rigs, Reefs, 

and Wrecks).......................................................................................................... 451

Figure 10-111. Photograph of net recovered from Ewing Bank Wreck (University of West 

Florida). ................................................................................................................ 452

Figure 10-112. Photograph of Muntz Metal sheathing recovered from Ewing Bank Wreck 

Site (University of West Florida). ........................................................................ 453

Figure 10-113. Close-up of Muntz Metal maker's stamp on sheathing sample recovered from 

Ewing Bank Wreck (University of West Florida). ............................................... 453

Figure 10-114. Starboard Signal Lantern near the Stern. .......................................................... 455

Figure 10-115. Green Lantern Wreck Site drawing based on ROV investigations. ................. 457

Figure 10-116. View of aft starboard frames and ceramic dish at the Green Lantern Wreck... 458

Figure 10-117. Diagonal foiling observed in sheathing (tarboard side) on the Green Lantern

Wreck. .................................................................................................................. 459

Figure 10-118. Bow of the Green Lantern Wreck (view from starboard side). ........................ 460

Figure 10-119. Close-up of bobstay fittings and draft marks on the Green Lantern Wreck..... 460

Figure 10-120. Windlass lying to the port bow of the Green Lantern Wreck........................... 461

Figure 10-121. Copper tubing and possible windlass bitt (upside down) at the Green Lantern

Wreck site............................................................................................................. 462

Figure 10-122. Small bell and round sheet of glass (setting on edge) at the Green Lantern

Wreck site............................................................................................................. 463

Figure 10-123. Port signal lantern of the Green Lantern Wreck............................................... 463

Figure 10-124. Possible bilge pump and pipe at the Green Lantern Wreck site....................... 464

Figure 10-125. Port side view of the rudder, and gudgeon and pintle at the Green Lantern

Wreck site............................................................................................................. 465

Figure 10-126. Bell recovered from the Green Lantern Wreck (post-conservation). ............... 466

Figure 10-127. Wooden sheave recovered from the Green Lantern Wreck (preconservation). ....................................................................................................... 467

Figure 10-128. Fork recovered from the Green Lantern Wreck ............................................... 468
xxxv

Figure 10-129. Ironstone plate recovered from the Green Lantern Wreck. .............................. 468

Figure 10-130. Navigation lantern recovered from the Green Lantern Wreck. ........................ 469

Figure 10-131. Copper plug from the Green Lantern Wreck (post-conservation).................... 469

Figure 10-132. GUCCI Microbial Test Platform deployed along the starboard side of the 

Green Lantern Wreck site. ................................................................................... 470

Figure 10-133. Gulfoil circa 1912.(Independence Seaport Museum)........................................ 471

Figure 10-134. Architectural drawing of the Gulfoil.(International Marine Engineering 

1912)..................................................................................................................... 472

Figure 10-135. Figure of Isherwood System of Ship Construction. (U.S. patent 1,029,546 

1912)..................................................................................................................... 474

Figure 10-136. 2009 Side scan sonar mosaic of the Gulfoil site (C & C Technologies, Inc.)... 477

Figure 10-137. Deck grating from Gulfoil (left) and deck grating from Jeremiah O’Brien 

(right) (Jason II ROV camera; William M. Briggs, 1012)................................... 478

Figure 10-138. Buckle in bow of the Gulfoil............................................................................. 479

Figure 10-139. Forward hull damage in the Guloil (C&C Photo mosaic)................................. 480

Figure 10-140. Deck plate/cargo hatches from the Gulfoil associated with hull damage. ........ 481

Figure 10-141. Gulfoil’s stack and ship’s whistle. .................................................................... 481

Figure 10-142. Wheelhouse coral growth on the Gulfoil. ......................................................... 482

Figure 10-143. Ammunition box with shell casings on the Gulfoil........................................... 482

Figure 10-144. Hole from the second torpedo. .......................................................................... 483

Figure 10-145. Gulfoil’s 4-inch gun with auxiliary steering on the left side of the photo. ....... 484

Figure 10-146. Gulfoil’s transom with a portion of the name visible........................................ 484

Figure 10-147. Estimated attack scenario on Gulfoil based on torpedoes approaching 

perpendicular to the tanker. Red shows the first torpedo hit and blues shows 

the second. ............................................................................................................ 486

Figure 10-148. Sonar mosaic image with estimated Gulfoil surface attack and sinking 

scenario (Sonar data courtesy of C & C Technologies, Inc.). .............................. 488

Figure 10-149. Tanker Gulfpenn, photograph taken by the United States Coast Guard 

(Courtesy of Mariner’s Museum, Newport News, Virginia). .............................. 490

Figure 10-150. Architectural drawing of the tanker Agwihavre or “Gulfpenn,” by the Sun 

Shipbuilding Company, July 8, 1920 (From the Independence Seaport Museum 

collection)............................................................................................................. 491

Figure 10-151. Side scan sonar image of Gulfpenn from the Texas A&M University deeptow system (Courtesy of Shell International Exploration and Production Inc.). . 492

Figure 10-152. Site Map of the Gulfpenn Wreck Site base on ROV investigations. ................ 495

Figure 10-153. Bow of the Gulfpenn. ........................................................................................ 496
xxxvi

Figure 10-154. Site drawing of Gulfpenn’s main structure (Drawn by Robert A. Church). ..... 497

Figure 10-155. Top of Gulfpenn’s superstructure showing the bridge telegraph lying across 

the exposed deck frame supports.......................................................................... 498

Figure 10-156. Breach in the Gulfpenn’s hull along the vessel’s starboard side...................... 499

Figure 10-157. Foot of the Gulfpenn’s main mast lying on the deck. ....................................... 499

Figure 10-158. Remains of the Gulfpenn’s docking helm control on the aft deckhouse........... 500

Figure 10-159. Possible section of the Gulfpenn’s detached stern. ........................................... 501

Figure 10-160. a) Vent hood (left) lying near the separated stern section. b) Vent hood 

(right) lying near the northern extent of the Gulfpenn’s debris field. .................. 501

Figure 10-161. Lifeboat from Gulfpenn in the debris field (Photo mosaic). ............................. 502

Figure 10-162. Gulfpenn’s main stack, lying to the vessel’s starboard side (Photo mosaic). ... 502

Figure 10-163. U-166 at sea in early 1942 (Kuhlmann Collection courtesy of the PAST 

Foundation and the National D-day Museum). .................................................... 504

Figure 10-164. Schematic of a Type IXC U-boat (Courtesy of National Park Service and 

PAST Foundation)................................................................................................ 504

Figure 10-165. Oberleutnantzur See Hans-Günther Kuhlmann (Kuhlmann Collection 

courtesy of the PAST Foundation and the National D-day Museum). ................ 505

Figure 10-166. An undated photograph of PC-566 (Courtesy of Mariner’s Museum). ............ 506

Figure 10-167. High-resolution side scan sonar image of U-166, 2001 (Courtesy of BP, 

Shell, and the National D-Day Museum). ............................................................ 509

Figure 10-168. Bathymetric data collected in 2001 showing the U-166 wreck site (Courtesy 

of BP, Shell, and the National D-day Museum)................................................... 510

Figure 10-169. Microbiological experiments with BARTS and etch tests (left) and test 

platforms (right). .................................................................................................. 512

Figure 10-170. Images of the long term microbiological experiments on the U-166's stern 

(left) and bow (right) taken during the Lophelia II 2010 field cruise. ................. 513

Figure 11-1. Video tour on Google Earth. ................................................................................. 520

Figure 12-1. Local-scale habitat suitability models for L. pertusa. Warmer colors indicate 

locations that are predicted to be more suitable. Black points indicate 

occurrences used to train and test the models. Note differences in scale............. 530

Figure 12-2. Response of the predicted habitat suitability for L. pertusa to changes in 

bathymetric position index (BPI) calculated at the 500 m scale for local scale 

models. Error bars indicate standard deviation. In general, locations with higher 

BPI values were predicted to be more suitable for L. pertusa. ............................ 531

Figure 12-3. Response of the predicted habitat suitability for L. pertusa to changes in depth 

(m) in local scale models. Error bars indicate standard deviation. In general, L. 

pertusa had the highest suitability indices between depths of approximately 

300-500 m............................................................................................................. 533
xxxvii

Figure 12-4. Response of the predicted habitat suitability for L. pertusa to changes in seismic 

reflectivity data, averaged across all sites. Higher reflectivity values indicate 

the presence of hard substrata. Locations with very high reflectivity values had 

significantly higher suitability indices than sites with low or very low 

reflectivity values (Kruskal- Wallis p<0.01, post-hoc Tukey p<0.05). Error bars 

indicate standard deviation................................................................................... 534

Figure 12-5. Enlarged view of habitat suitability maps for local scale L. pertusa models at 

VK826. A) Original VK826 model. B) Test model trained using only the 

transect occurrence data from Sentry. The two models were highly correlated 

(Pearson’s correlation, r=0.91, p<0.01) and were not significantly different 

from each other under the identity test (I=0.95, p>0.05). Warmer colors 

indicate locations that are predicted to be more suitable. Black points indicate 

occurrences used to train the models.................................................................... 535

Figure 12-6. Local scale habitat suitability models for L. glaberrima. Warmer colors indicate 

locations that are predicted to be more suitable. Black points indicate 

occurrences used to train and test the models. Note difference in scale. ............. 536

Figure 12-7. Response of the predicted habitat suitability for L. glaberrima to changes in 

bathymetric position index (BPI) calculated at the 500 m scale for local scale 

models. Error bars indicate standard deviation. ................................................... 537

Figure 12-8. Response of the predicted habitat suitability for L. glaberrima to changes in 

depth (m) for local scale models. Error bars indicate standard deviation. ........... 538

Figure 12-9. Response of the predicted habitat suitability for L. glaberrima to changes in 

seismic reflectivity data, averaged across VK862/906 and VK826. Error bars 

indicate standard deviation................................................................................... 538

Figure 12-10. Local scale habitat suitability models for Callogorgia spp. Warmer colors 

indicate locations that are predicted to be more suitable. Black points indicate 

occurrences used to train and test the models. Note differences in scale. GC140 

= C. gracilis, VK862/906, GB299 = C. a. americana, VK826, GC234, MC751, 

MC885, GC246 = C. a. delta. .............................................................................. 540

Figure 12-11. Response of the predicted habitat suitability for Callogorgia spp. to changes in 

depth (m) for local scale models. Error bars indicate standard deviation. GC140 

= C. gracilis, VK862/906, GB299 = C. a. americana, VK826, GC234, MC751, 

MC885, GC246 = C. a. delta. .............................................................................. 541

Figure 12-12. Response of the predicted habitat suitability for Callogorgia spp. to changes in 

BPI calculated at the 500 m scale for local scale models. Error bars indicate 

standard deviation. GC140 = C. gracilis, VK862/906, GB299 = C. a. 

americana, VK826, GC234, MC751, MC885, GC246 = C. a. delta................... 542

Figure 12-13. Response of the predicted habitat suitability for C. a. delta to changes in 

seismic reflectivity data, averaged across VK826, MC751, MC885, and 

GC234. Locations with very high reflectivity values had significantly higher 

suitability indices (ANOVA, p<0.01, post-hoc Holm-Sidak p<0.05) than sites 

with low and very low reflectivity values. Error bars indicate standard 

deviation. .............................................................................................................. 544
xxxviii

Figure 12-14. Suitability indices of Callogorgia spp. relative to various environmental 

parameters for mosaic models. Open circles = C. gracilis, closed circles = C. a. 

delta...................................................................................................................... 546

Figure 12-15. Large scale habitat suitability model for cold-water corals in the northern 

GoM. Warmer colors indicate locations predicted to be more suitable. Black 

triangles indicate the most intensively surveyed sites (west to east: GB299, 

GC354, GC140, GC246, GC249, MC751, MC885, VK862, VK906, VK826)... 548

Figure 12-16. Response of the predicted habitat suitability for cold-water coral species to 

changes in depth (m) for large scale models. Error bars indicate standard 

deviation. Only depths shallower than 1000 m are shown................................... 550

Figure 12-17. Response of the predicted habitat suitability for cold-water coral species to the 

presence or absence of hard bottom for large scale models. Error bars indicate 

standard deviation. Suitability was significantly higher at locations with hard 

bottoms at all sites (t-test, two-tailed |p|<0.05). ................................................... 552

Figure 14-1. A typical bottom longline used for reef fish in the Gulf of Mexico (from CSA 

2002)..................................................................................................................... 584

Figure 14-2. Configuration of a standard shrimp trawl used for shallow water penaeid shrimp 

in the Gulf of Mexico. Image courtesy NOAA Fisheries..................................... 585

Figure 14-3. . Diagram of shrimp trawl configuration typically used for shallow water 

penaeid shrimp in the Gulf of Mexico. This arrangement is also used in 

deepwater trawling for royal red shrimp. Image courtesy NOAA Fisheries....... 586

Figure 14-4. Historical landings for royal red shrimp in the Gulf of Mexico. .......................... 587

Figure 14-5. NMFS statistical areas for the Gulf of Mexico, grids 1 to 21. .............................. 588

Figure 14-6. Known Lophelia pertusa sites in the Gulf of Mexico, with 200 and 600 m 

contours. Open circles represent sites discussed in Shroeder et al. 2005. Open 

triangles are sites visited during Lophelia II cruises............................................ 589

Figure 14-7. Known Lophelia pertusa sites in the Gulf of Mexico with NMFS grid overlay... 590

Figure 14-8. Electronic Logbook (ELB) records of shrimp trawl locations for the Gulf of 

Mexico made in 2008. The deep locations suggests trawling for royal red 

shrimp in the vicinity of known Lophelia coral sites. Data from Gallaway et al. 

2009...................................................................................................................... 591

Figure 14-9. Royal red shrimp trawling grounds in the vicinity of known Lophelia coral 

sites. From Bullis 1956........................................................................................ 592

Figure 14-10. Summary of landings and trips for royal red shrimp, 2000-2008, by NMFS 

Statistical Grid. Data provided by J. Nance, NOAA Fisheries Galveston Lab. 

Highest activity occurs in the Dry Tortugas (1) and Mississippi Delta/DeSoto 

Canyon (10) regions. ............................................................................................ 593

Figure 14-11. Summary of trips targeting deepwater reef fishes, per NMFS statistical grid 

2007-2009, from the non-confidential portion of the reef fish logbooks............. 594
xxxix

Figure 14-12. Summary of trips targeting deepwater reef fishes from the reef fish log book 

(top), and catch in pounds per trip, 1990-2009 summed across the Gulf of 

Mexico.................................................................................................................. 595

Figure 14-13. Landings in pounds for deepwater groupers (top) and tilefish (bottom), total 

catch from 2000 through 2009, based on reported state landings summed across 

the Gulf of Mexico. .............................................................................................. 597

Figure 14-14. Landings in pounds for select deepwater species, total catch from 2000 

through 2009, based on reported state landings summed across the Gulf of 

Mexico.................................................................................................................. 598

Figure 14-15. Summary of deepwater grouper landings in pounds per trip, (top), and total 

barrelfish landings (bottom) summed across the Gulf of Mexico for years 1990-

2009...................................................................................................................... 599

Figure 14-16. Habitat Areas of Particular Concern (HAPCs) designated in the 

Comprehensive Ecosystem-Based Amendment 1, by the South Atlantic 

Fisheries Management Council in September 2009, pending final approval by 

the Secretary of Commerce. From SAFMC 2009................................................ 600

xl

LIST OF TABLES

Table 2-1. Sites Occupied during Cruise 1 .................................................................................. 11

Table 2-2. Sites Occupied during Cruise 2 .................................................................................. 15

Table 2-3. Sites Characterized Listed in Chronological Order.................................................... 18

Table 2-4. Sites Characterized Listed in Chronological Order.................................................... 20

Table 3-1. Carbonate Chemistry Parameters of Deep-water Sites in the Northern GoM............ 83

Table 3-2. LSU Deep Coral Study Moorings at Green Canyon 852 ........................................... 89

Table 3-3. Basic Statistics for Green Canyon 252 Mooring Deployment ................................... 90

Table 3-4. Basic Statistics for Vioska Knoll 826 Mooring Deployment..................................... 98

Table 4-1. Summary of photographic samples taken at each site including the number of 

photographs and total area in meters of the area surveyed................................... 118

Table 4-2. Mobile and sessile fauna observed in photographic transects at three study sites. .. 120

Table 4-3. Photomosaic designations, locations, visit dates, and areal extents........................ 128

Table 4-4. Collection information for all coral pot samples taken during this study ................ 185

Table 4-5. Summary statistics from community collections .................................................... 186

Table 4-6. Composition and distribution of coral associated symbionts by coral host type. .... 193

Table 4-7. Abundance of coral associates across five different phyla observed in a subset of 

coral colonies imaged during the 2009 cruise. ..................................................... 194

Table 5-1. PCR primers and protocols used to amplify targeted gene regions.......................... 204

Table 5-2. Reads obtained from 454 sequencing and subsequent results from a microsatellite 

discovery program (QDD2, Meglecz and Martin 2011) ...................................... 220

Table 5-3. Pairwise uncorrected p-distances (%) for Callogorgia species at (A) 

mitochondrial cox1+igr1+mtMutS, (B) nuclear 28S, and (C) both 

mitochondrial and nuclear loci............................................................................. 222

Table 5-4. Pairwise uncorrected p-distances (%) for Paramuricea spp. at mt 

cox1+igr1+mtMutS .............................................................................................. 224

Table 5-5. Locus name, primer sequences, type of fluorescent label on each forward primer, 

repeat motif, size range in base pairs. For each species, N=number of 

individuals genotyped, NA=number of alleles, HO =observed heterozygosity, 

HE=expected heterozygosity and pHWE =p-value indicating departure from 

Hardy Weinberg equilibrium per locus using a Chi-Square Test. A Bonferroni 

adjustment was made to α. Significance (*) = p<0.004 ....................................... 227

Table 5-6. Pairwise FST values among sites arranged by increasing depth. FST values in 

bold are significant (AMOVA, Bonferroni adjustment, p<0.003). ...................... 229
xli

Table 5-7. Leiopathes glaberrima samples from the GoM. Two lineages (L1 and L2) were 

identified with microsatellite (Msat) loci. The total number of samples (N) and 

number of distinct multilocus genotypes, Ng, as identified by microsatellite 

genotyping is indicated. Samples were categorized by sampling depth (in 50 m 

intervals) and colony color when available .......................................................... 233

Table 5-8. Samples (N) of Leiopathes glaberrima were sequenced at three mitochondrial loci 

(COI, ND and TRP) from five sites in the GoM.................................................. 234

Table 5-9. Microsatellite loci developed for L. glaberrima. The ten microsatellite loci 

developed for L. glaberrima were amplified in two multiplexes (plex 1-2) and 

three singleplex reaction. Given is the locus name, primer sequences, repeat 

type followed by the number of repeats and the size range of the alleles 

amplified in base pairs (bp). Annealing temperature was 54oC for Multiplex 1 

and BC19, 57oC for Multiplex 2, and 55oC for singleplexes 34 and 36. Forward 

primers were fluorescently labeled with one of four dyes (6FAM, VIC, PET or 

NED) .................................................................................................................... 235

Table 5-10 Leiopathes glaberrima microsatellite loci. Given are: N = number of samples 

genotyped at that locus, Na = No. of Different Alleles, Ho = Observed 

Heterozygosity, He = Expected Heterozygosity, Ht = Total Expected 

Heterozygosity, F = Fixation Index. Fis = (Mean He - Mean Ho) / Mean He, Fit 

= (Ht - Mean Ho) / Ht, Fst = (Ht - Mean He) / Ht. SE = standard error. 

Calculated by GenAlEx vers. 6.5 ......................................................................... 237

Table 5-11. Analysis of molecular variance (AMOVA) among sites and lineages (L1 and 

L2). Within individual analysis was suppressed and significance evaluated 

based on 999 permutations across the whole dataset. % = percent of the 

estimated total variance. Df = de.......................................................................... 237

Table 5-12. Spatial spread of genets (m) for collections with good navigational data. 

Navigational accuracy within a single cruise is generally about +/- 5 m at this 

depth using USBL alone and about twice that (+/- 10 m) when data from 

independent visits are combined. In many cases distances between corals were 

determined using doppler velocity navigation streams during a single dive and 

this can result in paired distance estimates accurate to about 0.5 m. N = number 

of ramets per genet. SD = standard deviation, * only a single clone pair was 

identified............................................................................................................... 240

Table 6-1. δ

13C and δ15N compositions for all soft corals sampled in this study ...................... 249

Table 6-2. δ13C and δ15N values of octocorals and their epizoic ophiuroids (oph.). Where 

more than one ophiuroid was present on the same coral, the coral stable isotope 

data are repeated on a separate line ...................................................................... 253

Table 7-1. Experimental conditions (mean ± S.D.) of pH experiment ...................................... 275

Table 7-2. Pairwise comparisons ( = 0.05) of pH among treatments in group 1 pH 

experiment............................................................................................................ 276

Table 7-3. Pairwise comparisons ( = 0.05) of pH among treatments in group 2 pH 

experiment............................................................................................................ 276
xlii

Table 7-4. Pairwise comparisons ( = 0.05) of Ωarag among treatments in group 1 pH 

experiment............................................................................................................ 277

Table 7-5. Pairwise comparisons ( = 0.05) of Ωarag among treatments in group 2 pH 

experiment............................................................................................................ 277

Table 7-6. Results from Kruskal-Wallis tests ( = 0.05) on tank effects (differences in 

growth rate among tanks) in pH experiment ........................................................ 279

Table 7-7. Experimental conditions (mean ± s.d.) of temperature experiment ........................ 283

Table 7-8. Pairwise comparisons ( = 0.05) of temperature among treatments in the 

temperature experiment........................................................................................ 283

Table 7-9. Results from Kruskal-Wallis tests ( = 0.05) on tank effects (differences in 

growth rate among tanks) in temperature experiment.......................................... 285

Table 7-10. Pairwise comparisons ( = 0.05) of dissolved oxygen among treatments in the 

dissolved oxygen experiment ............................................................................... 287

Table 8-1. Structure characteristics. and L. pertusa occurrence and growth rates .................... 306

Table 8-2. Regression statistics for: Growth rate vs. maximum age of corals (Figure 8-23).... 311

Table 9-1. Core acquisition data ................................................................................................ 325

Table 9-2. Radiocarbon Dating.................................................................................................. 335

Table 10-1 Key Archaeological Component Personnel............................................................ 344

Table 10-2. 7,000 Foot Wreck Anchor Data Information ......................................................... 404

Table 10-3. Patents awarded to David Baker............................................................................. 412

Table 10-4. Dimensions of Copper Sheathing from the 7,000 Foot Wreck .............................. 414

Table 10-5. Large fasteners identified at the Ewing Bank Wreck site....................................... 437

Table 11-1. Lophelia II Tour in Google Earth........................................................................... 521

Table 12-1. Input data and model evaluation for L. pertusa local scale models. The number 

of spatially explicit occurrences and the average AUC±s.d. are shown with 

significance marked (exact binomial test, *=p<0.01, ** p<0.001). The two 

primary explanatory variables for each model are listed along with the 

percentage of information contributed by each variable, as determined by 

jackknifing............................................................................................................ 529

Table 12-2. Input data and model evaluation for L. glaberrima local scale models. The 

number of spatially explicit occurrences and the average AUC±s.d. are shown 

with significance marked (exact binomial test, ** p<0.001). The two primary 

explanatory variables for each model are listed along with the percentage of 

information contributed by each variable, as determined by jackknifing ............ 537

Table 12-3. Callogorgia spp. Local-scale niche modeling results. The average test AUC of 

each model is listed along with model significance (exact binomial test, * 

p<0.05, ** p<0.01). The two primary explanatory variables for each model are 
xliii

listed along with the percentage of information contributed by each variable, as 

determined by jackknifing.................................................................................... 539

Table 12-4. Model input and evaluation for Callogorgia spp. mosaic models. The average

test AUC of each model is listed along with model significance (exact binomial 

test, * p<0.05, ** p<0.01). The two primary explanatory variables for each 

model are listed along with the percentage of information contributed by each 

variable, as determined by jackknifing................................................................. 545

Table 12-5. Large scale modeling results and niche characteristics for each species. The 

average test AUC of each model is listed along with model significance (exact 

binomial test, ** p<0.01). The two primary explanatory variables for each 

model are listed along with the percentage of information contributed by each 

variable, as determined by jackknifing................................................................. 549

Table 12-6. Pearson’s correlation values (r) among environmental variables used to train 

large scale models. Significant correlations (two-way p<0.05) are indicated 

with an asterisk. Significant correlations with an r>0.10 are highlighted in greyN=673,646............................................................................................................ 551

Table 12-7. Niche overlap (I metric) between the large scale niche models of each species 

pair. Values closer to one indicate greater niche overlap and values closer to 

zero indicate greater divergence........................................................................... 553

Table 14-1. Number of vessels and trips for royal shrimp in the Gulf of Mexico, 2004-2008, 

from the NMFS logbook system SEFSC. ............................................................ 572

Table 14-2. Effort in miles of line and number of hooks from reef fish longline records 

showing depth information and landing selected species of deepwater grouper 

and tilefish. Data are from the NMFS logbook system, SEFSC. ........................ 596

Table 14-3. Lophelia sites known from the Gulf of Mexico. Sites no. 1 to 24 taken from 

Schroeder et al. 2005. Sites 25 to 42 visited during Lophelia II project cruises. 601

Table 14-4. Fishes with potential commercial value associated with deep hard bottom or 

coral communities below 200 m. ......................................................................... 602

Table 14-5. Deepwater shrimps of the western Atlantic Ocean associated soft bottom 

communities below 200 m. From Jones et al. 1994, originally described in 

Cervignon et al. 1993). ......................................................................................... 604

Table 14-6. Fish and invertebrate taxa taken commercially in the northern GOM (U.S. 

waters) in decreasing order of commercial dollar value. Deepwater Species 

designated in bold. All values are annual averages for the period 2000-2007. 

Source: Fisheries Statistics Division ST1 (FSD) of the NMFS (NMFS 2008). 

From LGL 2009.................................................................................................... 606

Table 14-7. Species listed in the Essential Fish Habitat Amendment to Gulf of Mexico 

Fishery Management Plans. Deepwater species in bold. Source: GMFMC 

(2005b). Used with permission from LGL 2009................................................. 609
1

1 INTRODUCTION

1.1 OVERVIEW

This document represents TDI-Brooks' Final Report for the Lophelia II Project, Contract 

M08PC20038, issued by the U.S. Department of the Interior, Bureau of Ocean Energy 

Management, Regulation and Enforcement (now the Bureau of Ocean Energy Management 

[BOEM]) “Exploration and Research of Northern Gulf of Mexico Deepwater Natural and 

Artificial Hard Bottom Habitats with Emphasis on Coral Communities: Reef, Rigs, and Wrecks. 

This report provides detailed information regarding the five (5) cruises completed during the field 

operations phase, the study sites selection process and sites visited with full descriptions of the 

conditions encountered both physically and biologically. The analytical results from the research 

effort includes community structure using photomosaics, trophic studies, laboratory experiments 

with Lophelia pertusa, archaeology, educational outreach and analyses of a Lophelia mound 

piston core study and commercial fisheries impact on deepwater corals presented in 15 sections. 

This report is the final product of Contract M08PC20038.

1.2 BACKGROUND

Over the last half century, offshore exploration for hydrocarbons in the northern Gulf of Mexico

(GoM) has advanced from the bays and inner shelf to the continental slope-to-continental rise 

transition. Geophysical and geotechnical data collected in support of both exploration and 

production has been largely responsible for the foundation of our present understanding of slope 

geology. This database emphasizes the extremely complex geological framework of the northern 

Gulf’s continental slope and the surprisingly important role that the expulsion of subsurface fluids 

and gases has on shaping surficial geology and biology of the modern seafloor. Regional 

topography of the slope consists of basins, knolls, ridges, and mounds derived from the dynamic 

adjustments of salt to the introduction of large volumes of sediment over long time scales. 

Superimposed on this underlying topography is a smaller class of mounds, flows, and hard-bottom 

areas that are the products of the transport of fluidized sediment, mineral-rich formation fluids, 

and hydrocarbons to the present sediment-water interface. The geologic response to the expulsion 

process is related both to the products being transported and the rate at which they arrive at the 

seafloor. Mud volcanoes and mudflows are typical of rapid flux settings where fluidized sediment 

is involved. Slow flux settings are mineral-prone. Authigenic carbonate mounds, hard grounds, 

crusts, and nodules are common to settings where hydrocarbons are involved. 

The authigenic carbonates that are a part of nearly every fluid-gas expulsion site provide the hard 

substrate necessary for many marine sessile organisms, particularly corals. Consumption of 

hydrocarbons by microorganisms at expulsion sites is intimately associated with carbonate 

precipitation and the production of hard substrates. Aerobic methane oxidation produces CO2 and 

decreases pH, favoring dissolution of carbonates (Aloisi et al., 2002). Anaerobic microbial sulfate 

reduction using hydrocarbon substrates causes sulfate depletion and simultaneous bicarbonate and 

hydrogen sulfide enrichments in sediments. The increase in carbonate alkalinity of pore fluids 

produces calcium-magnesium carbonate by-products (Ritger et al, 1987; Roberts and Aharon, 

1994). These carbonates take the form of distinct mounds with relief of up to 10 m, larger boulders 

and blocks, and low relief slabs and hard grounds.
2

Recent manned submersible and remotely operated vehicle (ROV) dives to the middle and lower 

continental slope confirm the existence of these hard substrates to the deepest parts of the slope. 

Direct observation and sampling of expulsion sites started in the mid-1980s on the upper slope. 

We now know from analysis of three-dimensional (3-D)-seismic data and submersible- ROV dives 

that numerous expulsion sites with hard substrates provide habitat for deep-water corals over the 

slope’s full depth range.

1.2.1 Deep-water Hard -Ground Communities 

In the context of this study, deep hard-ground communities of the GoM comprise all of the 

biological communities inhabiting natural or artificial hard substrates, excluding the 

chemosynthetic seep communities. These communities consist of foundation species, those species 

that form large complex habitats at these sites, and their associated fauna ranging in size from large 

mobile fishes to microscopic meiofauna. The most prominent foundation species in these 

communities are the deep-water (“cold-water”) corals. The terms “deep-water corals” or “coldwater corals” include relatives of the tropical reef-forming scleractinian corals, but also refer to a 

variety of other cnidarian taxa including antipatharians (black corals), gorgonians (including 

bamboo corals), alcyonaceans (soft corals), and stylasterine hydrocorals. Other taxa, including 

anemones and sponges are also significant contributors to the biogenic framework of these deepwater reef systems. When related to coral species, the term “deep water” refers to aphotic waters 

greater than 200 m depth.

In the GoM, deep-water corals are commonly found on seep-related authigenic carbonates. The 

most common species of reef-forming deep-water coral in the GoM is Lophelia pertusa

(=prolifera). This species was first recovered in the late 1800s by the U.S. Coast Survey Steamer 

Blake (Cairns 1978). L. pertusa “reefs” in the GoM were first reported from a deep water trawl 

taken by the motor vessel (M/V) Oregon in 1955 (Moore and Bullis, 1960). Recently, submersible 

observations have located L. pertusa in numerous additional locations on the upper slope of the 

northern GoM (Schroeder 2002, Schroeder et al. 2005, Cordes et al. 2006, Cordes et al. 2008, 

CSA, 2007) and this study has contributed significantly to our knowledge on the distribution of 

this coral. 

Deep-water corals have also been observed colonizing artificial substrates in the GoM. Previous 

studies have located coral communities on the shipwreck Gulfpenn in Mississippi Canyon (MC) 

lease block 497 (MC497). Two scleractinians, Lophelia pertusa and Pourtalosmilia conferta, were 

found on the Gulfpenn (Church et al. 2007). P. conferta was restricited to a solitary, medium size 

colony observed near the top of the starboard boom stanchion. L. pertusa was far more abundant, 

colonizing 12-15 percent of exposed surfaces and structures throughout the wreck. L. pertusa

appears to have developed most successfully on surfaces or structures that have a vertical 

orientation (e.g. hull, bulwarks and sides of the superstructures) or that have an upright (e.g. davits, 

masts, booms and stacks), raised (e.g. catwalks and deck piping), or open (e.g. railings and rigging) 

construction. The most extensive coral growth occurs along the railing, bulwarks and hull on the 

starboard side and on the deck piping and catwalks. At numerous locations clusters of adjacent 

colonies have coalesced into an initial phase of ‘thicket’ building. The largest development is a 6 

to 7 m high by 3 to 3.5 m wide aggregate of at least 5 or 6 coalescing colonies. L. pertusa was also 

found living on the sediment adjacent to the hull and colonizing wreckage scattered about in the 
3

debris field northwest and west of the Gulfpenn. In this study, a sister-ship sunk in the same era, 

the Gulfoil, was discovered. It was also covered with extensive L. pertusa growth coalescing into 

the thicket phase. These shipwrecks and others are discussed in Chapter 10.

Increasing industry activity in deepwater has resulted in the creation of numerous platforms in 

water depths exceeding 300 m. In areas where hard substrates are limiting, these platforms may 

significantly increase the potential range of corals and other hard-ground fauna. Growth of 

Lophelia pertusa had previously been noted on the Pompano platform in Viosca Knoll (VK)989. 

This study continued the exploration and characterization L. pertusa growth rates and patterns on 

several platforms, and examination of their potential connection to other coral populations and 

surrounding deep-water communities. 

1.2.2 Deep-water Coral Biology and Ecology

Although the existence of deep-water corals has been known since the first descriptions by 

Linnaeus in the mid 1700s (Cairns 2001) and the oceanographic research expeditions of the His 

Majesty’s Ship (H.M.S.) Challenger and H.M.S. Porcupine in the late 1800s (Rogers 1999), we 

are still in the process of describing their distribution and basic elements of their biology and 

ecology. The popular conception of corals is that they are restricted to the shallow waters of 

tropical seas; however, 65% of the known 5,160 species of corals occur in waters deeper than 50 

m across the globe (Roberts et al. 2009). 

The most well-known deep-water coral species is Lophelia pertusa, a cosmopolitan coral found in 

water depths from 39 m in Norwegian fjords to over 3,000 m on the Mid-Atlantic Ridge and some 

seamounts (Bett 1997, Rogers 1999). Current knowledge suggests that distribution, abundance, 

and growth of L. pertusa is strongly influenced by environmental factors such as temperature, food 

supply, hydrography, dissolved oxygen concentration, and carbonate chemistry (Rogers 1999; 

Thiem et al. 2006; Davies et al. 2010; Guinotte et al. 2006), and each subspecies varies according 

to latitude, depth, surface productivity, seafloor topography, and position on the ocean conveyor 

belt (Broecker 1991). L. pertusa is typically associated with temperatures from 4 to 12°C 

(Frederiksen et al. 1992; Freiwald et al. 1997), dissolved oxygen concentrations from 3 to 5 mL·L1

, and a relatively constant salinity from 35 to 37 (Roberts et al. 2003). There have been no previous 

studies characterizing the aragonite saturation state adjacent to L. pertusa reefs, although this is 

considered to be a significant factor in the worldwide distribution of scleractinians (Davies and 

Guinotte 2011). L. pertusa exhibits patchy distribution at local spatial scales, suggesting an 

influence of current regime on food delivery (Genin et al. 1986; Becker et al. 2009) and larval 

supply (Roberts et al. 2009).

L. pertusa develops from individual polyps, to larger “thickets”, to massive reef structures. It has 

separate sexes and exhibits seasonality in reproduction with spawning apparently occurring in 

September to October in the GoM (Brooke and Schroeder 2007), and February in the Northeast 

Atlantic (Waller and Tyler 2005). Gametes are released and fertilized externally, producing 

lecithotrophic planula larvae (Waller and Tyler 2005), which require hard substrata for settlement 

(Wilson 1979). Individual branches of coral grow slowly, and previous estimates of linear 

extension rates range from 2-30 mm∙yr-1, although pioneer colonies on man-made substrates may 

grow much faster (Mortensen and Rapp 1998; Gass and Roberts 2006). As the branches of the 

colony grow, new polyps are added via intra-tentacular budding. The rate of addition of new polyps 
4

in L. pertusa is poorly characterized, with most recent estimates approaching 1 polyp every 2 to 3 

years, though with a high level of uncertainty (Sabatier et al. 2012). Several studies of L. pertusa

reveal patterns of allometric growth, the differential extension of select parts of a colony relative 

to the whole (e.g. Mortensen 2001; Brooke and Young 2009), with younger polyps growing 

significantly faster than older polyps (Maier et al. 2009). Small, young colonies consisting of 

living, white coral polyps are normally positioned along the edge of rocky outcrops or authigenic 

carbonates. As they grow, larger thickets of coral are usually comprised of a periphery of living 

coral surrounding a central dead portion of coral skeleton that serve as substrate for secondary 

settlement of L. pertusa and other species of deep-water corals (Wilson 1979). Larger, reef-like 

structures may cover extensive areas. The largest known continuous reef structure is roughly oval 

in shape covering 13 km along its axis and 300 m in diameter and consists of coral matrices up to 

35 m thick (Freiwald et al. 1999). Carbon (14C) dating has placed the age of dead corals at the 

center of similar (but much smaller) structures in the GoM at over 40,000 years (Neumann et al. 

1977).

Deep-water corals are important sources of habitat heterogeneity on continental shelves 

worldwide. They create habitat for a diverse group of associated fauna that may occur in 

abundances orders of magnitude above that on the surrounding seafloor (Jensen and Frederiksen 

1992). In the Northeast Atlantic alone, over 1,300 species have been recorded living in and on L. 

pertusa habitats in physical and photographic samples (Rogers 1999; Roberts et al. 2006; Henry 

and Roberts 2007). On two reef structures alone in Norway, 256 species were recorded from 

recovered coral blocks (Jensen and Frederiksen 1992). In the Porcupine Seabight in the Northeast 

Atlantic, 313 taxa were collected in 7 box core samples from coral mounds (Henry and Roberts 

2007). The diversity of the community on these reefs rivals the diversity of many tropical 

zooxanthellate coral reefs (Rogers 1999). However, these studies all involved dredge and box core 

samples that include species that are likely not be intimately associated with coral structure but 

inhabit the sediments beneath the coral framework and in the case of dredges perhaps as much as 

100s of m away. In the GoM, 68 taxa of large macrofauna and megafauna (> 1 mm sieve size) 

were found in closely associated with L. pertusa in quantitative community collections obtained 

with custom collection devices deployed from a submersible (Cordes et al. 2008). Photographic 

surveys indicate that a variety of invertebrate and fish species occur primarily and possibly 

exclusively in these habitats (Ross and Quattrini 2007; Lessard-Pilon et al. 2010). Some associated 

species appear to have very specific interactions with L. pertusa including the polychaete Eunice

sp. which may help to assemble coral structure and the coralivorous gastropod Coralliophila sp. 

(Cordes et al. 2008; Becker et al. 2009). 

While L. pertusa remains the best-known deep-water corals species in the GoM in particular and 

the world in general, many other species of deep-water corals exist and are not as well studied. 

The number of described deep-water scleractinian coral species now exceeds the number of 

described shallow-water scleractinians (Cairns 2001). In the GoM, 63 species of azoozanthellate 

scleractinians have been reported (Cairns 1993). In addition to L. pertusa, 3 other species are 

known to form reef-like structures. Madrepora oculata is a cosmopolitan reef-forming species that 

has been found down to 1,500 m depth (Cairns 1978). Enallopsammia profunda is found to 2,165 

m depth and is another common component of the deep-water reef-forming coral assemblage 

(Rogers 1999). Solenosmilia variabilis has been documented in waters to 3,383 m (Cairns 1978). 

This species is a contributor to coral frameworks in the Atlantic (Rogers 1999) and is the most 
5

common deep-water reef species on Southwest Pacific seamounts (Koslow et al. 2001). All three

of these species were observed and collected at a recently discovered site in Green Canyon (GC) 

852 during the Minerals Management Service (MMS) /National Oceanic and Atmospheric 

Administration (NOAA) funded characterization of chemosynthetic communities in the deep GoM 

(Roberts et al. 2007). There are also at least 5 species of solitary scleractinians that contribute to 

the species richness of the deep-water coral community below 1,000 m in the GoM (Cairns 1978).

In addition to scleractinian corals, a number of gorgonian and antipatharian corals are present in 

deep waters in the GoM (Cairns 1978; Cairns 1993). They can occur in the same areas with 

extensive development of scleractinian corals as well as in areas lacking reef-building hard corals. 

In either case these taxa add significant habitat heterogeneity and vertical relief. Gorgonians 

(Anthozoa: Octocorallia: Gorgonacea) are some of the most common and conspicuous sessile coral 

reef fauna in the shallow GoM and Caribbean Sea (Cairns 1977), and occur worldwide deeper than 

4,200 m (Bayer 1956). Gorgonians create habitat for associated species of fish (Etnoyer and 

Warrenchuk 2007), invertebrates (Buhl-Mortensen and Mortensen 2005), and microbial fauna 

(Penn et al 2006). Gorgonians are also relatively long-lived organisms, with single colonies of 

Primnoa reseadiformis estimated to be between 150 (Andrews et al. 2002) and 500 years old (Risk 

et al. 2002). Recent reviews of octocoral diversity in the GoM place the total number of species at 

162 (Cairns and Bayer 2009). Gorgonacea in the Gulf occur from intermediate to abyssal depths 

(Isididae, 250-2,800 m; Primnoidae 200-1400 m) (Etnoyer, unpublished data). The most common 

deep-water species include the endemic primnoid Callogorgia americana delta that forms 

extensive stands at many of the Green Canyon sites and on carbonate blocks in Viosca Knoll (VK) 

826, and the broadly distributed bamboo coral Acanella eburnea. Precious corals (Coralliium spp.) 

are rare, but one colony was recently sampled at GC852 during the Chemo III project. 

Forty-two species of antipatharians have been recorded from the western Atlantic and about 30 of 

these have been found in the GoM (Cairns et al., 1993). The greatest species diversity occurs in a 

depth range of about 20 to 200 m, however, some GoM species have been reported from depths 

greater than 300 m, including Elatopathes abietina (Pourtales), Bathypathes patula Brook, 

Aphanipathes pedata Gray, Stylopathes columnaris (Duchassaing and Michelotti), Sibopathes 

macrospina (Opresko), Tanacetipathes hirta (Gray), Parantipathes tetrasticha (Pourtales), and 

Leiopathes glaberrima (Esper). Other antipatharian taxa that might be expected to occur in deep 

waters in the GOM are species of the genera Chrysopathes spp., Heliopathes, and Acanthopathes. 

Although many antipatharian species form colonies of relatively small size, some are large enough 

to create habitat for many other marine organisms (see Yoklavich and Love, 2005). There is, 

however, very little information on the habitat-forming species in the deep waters of the GoM, and 

very little is known about the distribution of antipatharians in the deep sea in general. In deep reef 

and upper slope habitats, antipatharians can be a major component of the sessile benthic fauna, 

and it is likely that they play a similar role in the deep sea – particularly in locations characterized 

by distinct topographic features, hard bottom, and relatively fast currents, such as many of the hard 

grounds of the GoM slope. 

1.2.3 Deep-sea Environmental Issues and Impacts

With the current push to expand energy reserves in U.S. territorial waters, the activities of energy 

companies in the deep GoM will continue to increase. As of April 2013, 5,891 active leases are 

currently held by industry, with a significant portion (74%) concentrated within the north-central 
6

GoM. Lease statistics from 2000 to 2012 show an expansion of industry interest into progressively 

deeper waters; in 2012, 58% of industry bids in the north-central GoM were made for areas deeper 

than 200 m. 

Exploration and extraction of energy reserves impact hard-bottom communities in the GoM 

because the formation and occurrence of authigenic carbonates is strongly correlated with 

chemosynthetic activity associated with hydrocarbon seeps in this region (Formolo et al. 2004). 

Therefore, the substrate for coral settlement is largely tied to the occurrence of existing or relict 

hydrocarbon seeps in the GoM. In shallow water corals, direct exposure to hydrocarbons can cause 

reductions in growth and fecundity, prevention of settlement, and even whole colony mortality 

(Loya and Rinkevich 1980). In the vicinity of oil platforms in the GoM, increased abundances of 

poly-aromatic hydrocarbons (PAHs) and metals (Ba, Hg, Pb, and Zn) as well as organic 

enrichment resulting from the discharge of well cuttings have been shown to lead to changes in 

infaunal community structure (Peterson et al., 1996). Drilling discharges of cuttings and fluids will 

smother fauna, cause some mortality and alter both the geological and geochemical habitat. Such 

impacts may be greater in deep development due to increased use of multiple wells drilled through 

a single seafloor template and use of bio-active synthetic drilling fluids. The dependence of deep 

hard-ground fauna on very sparse suspended detritus may make these communities especially 

sensitive to the added particulate influx since this may clog filter apparatus and lead to stress 

responses. In addition, the chains and wire ropes used to anchor floating deep-water oil platforms 

to the bottom have been implicated as the cause of damage to Lophelia reefs in the Viosca Knoll 

region of the Gulf (Schroeder 2002). Once sites of significant coral abundance have been 

identified, the standoff and site approval requirements of Notice to Leessees (NTL) 2000-G20 

should provide adequate protection from routine operations. In a more general sense, the 

establishment of a deep-water coral research program in the deep GoM prior to significant 

anthropogenic disturbance will provide us with a background against which to measure future 

impacts and may improve our understanding of other deep-water coral habitats in areas which have 

already been impacted by human activity. 

The current lack of a significant deep-water fishery in the GoM also makes this an ideal setting for 

the study of deep-water coral habitats in the absence of impact from such fisheries. In other regions, 

the past and ongoing fishery pressure on populations of deep water fishes with long life spans such 

as rockfish (Sebastes spp.), orange roughy (Hoplostethus atlanticus), and pelagic armourhead 

(Pseudopentaceros wheeleri) has resulted in significant damage to coral communities from deepwater fisheries (Rogers 1999, Koslow et al. 2001, Roberts et al. 2002). The deepest commercial 

fisheries for bottom-dwelling fishes in the GoM remain in waters overlying the continental shelf. 

However, the presence of economically viable fishery species such as the longfin hake (Phycis 

chesteri), wreckfish (Polyprion americanus), blackbelly rosefish (Heliocolenus dactylopterus) and 

numerous grenadiers (Macrouridae) in deep waters (McEachran and Fechhelm 1998) and 

specifically at L. pertusa banks (Sulak et al. 2007) suggests that there may be current fishery 

activity that has been largely undocumented, and that a larger commercial deep-water fishery in 

the GoM may yet develop. 

The correlation between the distribution of deep-water corals and the location of deep water human 

activity has led to recent conservation efforts on the behalf of deep-water corals. For example, the 

Darwin Mounds off Scotland (Masson et al. 2003) were recently proposed by the European Union 

as Special Areas of Conservation. The Lophelia reefs off Norway are protected under the Coral 
7

Protection Regulation of 1999 (Fossa et al. 2002). In the areas surrounding the Azores, Madeira, 

and Canary Islands, all bottom trawling is prohibited in depths > 200 m. Off New Zealand and 

Australia, seamounts are closed to dredging and trawling, and a marine protected area (MPA) was 

established to protect the scleractinian Solensmilia variabilis (Koslow et al. 2001). In 2005, the 

Aleutian Islands Habitat Conservation Area was established covering nearly 1 million km2for 

deepwater coral protection off Alaska. Bottom trawling is restricted in two conservation areas in 

Atlantic Canada and in canyons near George’s Bank off the New England coast. Off the southeast 

U.S. coast, a MPA exists for Oculina varicosa off the coast of Florida and a large deep-water coral 

Habitat Area of Particular Concern has been proposed. In the GoM, the high-density L. pertusa

portion of Viosca Knoll 826 has been proposed as a conservation area. To compliment these 

activities in the U.S., the 2007 reauthorization of the Magnuson-Stevens Fishery Conservation and 

Management Act called for the Deep Sea Coral Research and Technology Program to locate, map, 

and monitor activity in locations where deep-sea corals are known or likely to occur. In addition 

to the establishment of long term monitoring stations, the predictive capacity for determination of 

areas where corals are “likely to occur” was developed as a prime focus of the proposed research 

here and will be a significant tool for future management of deep coral communities in the GoM.

1.3 OBJECTIVES OF THE PROJECT

A primary goal of this study was to obtain a robust predictive capability for the occurrence of rich 

cnidarian (primarily scleractinian coral) hard-ground communities in the deep GoM. To achieve 

this long-term goal, this study accomplished eight interrelated and interdependent objectives:

1) Discovered and described numerous new locations at greater than 300 m depth in the 

GoM with extensive coral community development.

2) Established long term monitoring stations at many of these locations to allow study of 

natural and anthropogenic change over time.

3) Characterized the newly discovered communities geologically and biologically, and 

determined the primary factors that contribute to the biogeographic patterns of deep coral 

community biodiversity in the GoM.

4) Conducted laboratory experiments that provide a more comprehensive understanding of 

the fundamental processes that control the occurrence and distribution of L. pertusa in the 

GoM.

5) Gathered field data that constrain the environmental conditions that allow L. pertusa

community development and provide insights into how its distribution may change with 

changing climatic conditions.

6) Conducted genetic analysis of several different corals in order to better understand both 

deep coral phylogeography and the connectivity within coral taxa in the deep GoM.

7) Conducted an in depth study of the geologic history of the most significant new deepwater coral site discovered as part of this program 

8) Documented coral communities on artificial substrates and determined depths, densities 

and growth rates of L. pertusa, the key cnidarian foundation taxa on the substrates.

8

2 STUDY SITES AND FIELD ACTIVITY OVERVIEW

The program completed five cruises between 2008 and 2012 to examine specific sites (and what 

you were looking for). Sites were identified using 3D seismic data initially and additional

methodology developed during the program and described below. Cruise overviews are presented 

in this chapter and much of the cruise details are in appendices.

2.1 SITE SELECTION

Most colonial corals require a hard substrate to settle and grow upon. In the deep GoM the majority 

of the sea floor is soft substrate unsuitable for coral growth, however free-living bacteria at sites 

of natural oil and gas seepage create conditions favorable for the formation of authigenic 

carbonates, which form hard-ground areas. Thus, sites of historic and current hydrocarbon seepage 

are nearly always associated with some degree of hard-ground development and when these hard

grounds are in appropriate locations they may harbor lush deep-sea coral communities. Industry 

datasets and investigations funded by BOEM and NOAA have shown these sites occur to the 

deepest parts of the continental slope. Exposed carbonates occur as nodular masses in 

unconsolidated surface sediments, slabs, boulders-blocks, or mounds of various sizes. The use of 

3D-seismic sea floor amplitude data for finding hard bottom areas associated with hydrocarbon 

seeps started in the early 1990s. However, during the BOEM Chemo III project we improved on 

earlier methodologies and developed considerable expertise in the use of 3D-seismic data to locate 

potential exposed hard grounds through ouranalysis of sea floor reflectivity or surface amplitude 

derived from 3D-seismic data. Consistent with earlier research, on hydrocarbon seeps, we 

followed up on the potential sites identified in this project with remotely sensed seismic data with 

in-situ verification of the presence of megafaunal communities using cameras and ROVs.

The basic data sets used in this study consisted of 192 3D-seismic surveys acquired over 76,000 

mi2(196.850 km2) across the upper, middle, and lower continental slope of the northern and 

northwestern GoM. These are data collected by oil and gas companies as well as speculative 

acquisitions by survey companies. The data are held by BOEM in their New Orleans, Louisiana 

office.

For the 3D-seismic analysis, reflection strength (amplitude) and phase were determined by using 

a 10 millisecond window from the sediment-water interface into the shallow subsurface. This 

window translates into an interval approximately 7.6 m (25 ft) thick. Phase is a seismic attribute 

related to amplitude and has a sawtooth appearance resulting from amplitude maxima and minima. 

Phase can be both positive and negative with values from 180o to -180o depending on the amplitude 

trace. A zero phase value corresponds to amplitude maxima, whereas minimal amplitude values 

cause a phase reversal. Phase reversal can indicate the presence of gas bubbles or pockets

contained in near-surface sediments. As applied in the study, phase helps define “fast” (usually 

hard ) and slow” (usually soft, gas charge ) areas of the seabed and associated shallow subsurface. 

The continental slope of the northern GoM is punctuated with seafloor “bright spots,” areas of 

high seismic energy reflectivity or amplitude (Roberts et al., 2006). At the start of this program 

numerous sites were selected for further analysis based on their 3D-seismic amplitude character. 

This work involved accessing the extensive and slope-wide BOEM seismic database. Selection of 
9

sea floor amplitude anomalies that fit the project requirements was conducted in cooperation with 

William Shedd of BOEM. For this stage of selection, extensive (and, in many cases overlapping)

time data from the 3D seismic surveys was used to generate bathymetry. In most 3D-seismic data 

sets, the sea floor reflector was strong and well suited to the automatic picking programs on the 

BOEM New Orleans Office Sun Workstation using Geoquest’s “Autopix” and “ASAP” in 

“IESX”. The sea floor horizon was given a unique, consistent name for each survey (wb-survey 

permit name) to avoid amplitude display problems caused by the wide variation in amplitude 

scaling between surveys. Due to time and data storage constraints, the sea floor amplitude 

interpretations were not normalized. Every seafloor horizon was defined as a positive 

(compressional) event in the horizon settings. As many seed lines were interpreted by hand as was 

deemed necessary for each survey, depending on the complexity and rugosity of the sea floor 

bathymetry and the highly variable amplitude response. The automatic picking program was then 

started and let run overnight. Upon completion, the resulting interpretation was quality checked 

for bad picks and gaps. This procedure proved to be especially important in some high dip and 

complex areas to “clean up” the interpretation.

Upon completion of the initial picking process, amplitude interpretation of each survey was posted 

and potential hard ground sites identified. Those that have high positive amplitudes were outlined 

with red fault polygons, interpreted as areas with extensive authigenic carbonates and/or hydrates 

that should have anomalously strong positive reflection coefficients. Those areas with low positive 

responses or negative responses (phase reversals from peak to trough), often embedded within the 

high positive areas, were outlined with green fault polygons, interpreted as areas of very high flux 

rates with gas saturated muds that should have weak positive to negative reflective coefficients. 

Many sites with abundant chemosynthetic and hard bottom communities have been found using 

the BOEM seismic database and the techniques described above. During this project, BOEM used 

this basic methodology to identify over 23,000 potential hard grounds on the northern GoM

continental slope (see “wb-anomaly” at http://www.boem.gov/Oil-and-Gas-EnergyProgram/Mapping-and-Data/Map-Gallery/Seismic-Water-Bottom-Anomalies-Map-Gallery.aspx) 

(Figure 2-1).

Figure 2-1. Seismic seafloor amplitude anomaly distribution, from BOEM website. 

Over 23,000 positive anomalies shown in red are potential hard grounds.

TX

LA

N
10

For this project, initial site selection was further refined using criteria likely to influence the 

occurrence of deep-water corals, for the following reasons. The 3D seismic data detect hard bottom 

conditions in the upper 7-8 m of the shallow subsurface, and is not always a reliable indicator of 

exposed carbonates. The hard reflector could be buried by meters of sediment, rendering it 

inaccessible to corals. This factor was considered in site selection. In ddition, one of the criteria 

used during the second stage of site selection was a local topography with potential exposure to 

bottom currents that would remove sediment accumulation from older hard grounds. Because 

currents also deliver food to the corals, local topographic highs, steep slopes, and generally rough 

topography were also important criteria in addition to recognition of hard-bottom areas in the 3D 

seismic data sets. 

Sites selected for further investigation were normally first surveyed using high quality multibeam 

sonar from a surface ship and by either a drift camera, a towed camera system, or an autonomous 

underwater vehicle (AUV). If any imaging system identified colonial corals in the area, the site 

was further investigated by ROV. In a few cases later in the program very favorable sites were 

explored by ROV without previous imaging. One example, the new sites on the West Florida 

Slope, were identified based on high quality multibeam maps and known coral occurrence on 

similar features in the area. Another example was the 338/294 site discovered by Jason based on 

3D-seismic data alone. 

Over the course of this project a new technique was employed that proved instrumental in the 

discovery of multiple sites in the vicinity of the Macondo well. Although a drift or towed camera 

system can be a very valuable discovery tool, these tools often miss sites because of the relative 

small areasthat are imaged and the possibility of missing exposed carbonates if they are not present 

in high density. As a result they are not reliable tools to confirm absence of corals in an area and 

are likely to miss isolated coral communities. As part of a Natural Resources Damage Assassment 

(NRDA) program the Principal Investigators (PIs) in collaboration with W. Shedd of BOEM 

selected a number of sites near the Macondo well using our normal criteria and then used the Sentry

AUV to first create a very high- (sub-meter) resolution bathymetric map of the area identified from 

an altitude of 25 m. From this map, the sub-areas with fine scale rugosity were identified (which 

often proved to be exposed carbonate boulders or slabs). These sub-areas were targeted for 

intensive imaging from an altitude of 5 m on a subsequent AUV dive. This technique was very 

successful and is recommended for intense exploration in geographically defined regions where 

confirmation of both presence and absence is an important consideration.

2.2 CRUISE OVERVIEWS

The Lophelia II project involved exploration and research of the northern GoM deepwater natural 

and artificial hard bottom habitats with emphasis on coral communities. It also included 

archeological studies of 7 shipwrecks and biological investigations of energy platforms. A total of 

five dedicated cruises were conducted as part of this program, and piston cores were collected 

during a sixth cruise primarily dedicated to other programs (see Section 9 of this report). The first 

Lophelia II cruise with a small survey ROV took place in September 2008, and the second cruise 

using the AUV Sentry in June 2009. Cruises 3 and 4, using the Jason II ROV were conducted in 

August–September 2009 and October-November 2010. A final cruise dedicated to work on energy 
11

platforms was conducted with the Kraken II ROV in July 2012. Full reports on all of these cruises 

have been supplied to BOEM.

2.2.1 Cruise 1: NOAA Ship Nancy Foster and SeaEye Falcon ROV

The Lophelia II Cruise 1 was conducted on the NOAA Ship Nancy Foster from September 2, 2008 

to October 2, 2008, and was the first cruise conducted for this contract. The cruise had two legs 

with a personnel change between the cruise legs. The cruise mobilized and embarked from 

Galveston, Texas, and returned to Gulfport, Mississippi September 17-19 for the personnel change. 

Five days were lost to weather on the first leg. Only a total of thirteen hours of bottom time with 

the ROV were achieved on the wreck sites over the entire first leg. Useful data was collected at 3 

wreck sites. The SeaEye Falcon ROV was used to explore and characterize wreck sites during the 

first leg and natural reef sites during the second.

The second leg embarked Gulfport Mississippi on September 20 and demobilized in Pascagoula, 

Mississippi on 2 October 2008. This leg was somewhat more successful, with only 2 days lost to 

weather. Of the 10 ROV lowerings, six reached the sea floor and worked for over 2 hours. 

Manipulator failures and ROV problems limited its usefulness to sites <600 m depth. Valuable 

photographic sampling and conductivity-temperature-depth (CTD) data were collected at 5 sites 

and multibeam data at a total of thirteen sites. Table 2-1 lists sites that were visited during Legs 1 

and 2 (Figure 2-2, Figure 2-3).

Table 2-1.

Sites Occupied during Cruise 1

Leg 1 Sites Leg 2 Sites

EW1008, EW Wreck AT47

MC497, Gulfpenn EB478

MC796, Gulfoil EW1009

GC245, Green Lantern GB201

GB535

GC140

GC201

GC234

GC246

MC539

MC751

MC885

VK906
12

Figure 2-2. Bathymetric map of the northern Gulf of Mexico showing shipwrecks and oil or gas platforms of interest

in Cruise 1
13

Figure 2-3. Cruise tracks for Leg 1 and Leg 2.

!.

!.

!.

!. !.

!. !.

#0!.

#0

#0

#0

Louisiana

Texas

Alabama Mississippi

Florida

50

250 500

100

3000

2000

1000

1000

250

2000

2000

2000

1000

2000

1000

2000 2000 2000

500

50

2000

100

2000

1000

1000 2000

2000

500

100

3000

2000

1000

2000

2000

100

2000

GC140

VK826VK786

MC539MC588

GC245GC297

MC796 MC497

EW1008

GB area

MC area

85°30'0"W

85°30'0"W

87°0'0"W

87°0'0"W

88°30'0"W

88°30'0"W

90°0'0"W

90°0'0"W

91°30'0"W

91°30'0"W

93°0'0"W

93°0'0"W

94°30'0"W

94°30'0"W 31°30'0"N 31°30'0"N 30°0'0"N 30°0'0"N 28°30'0"N 28°30'0"N 27°0'0"N 27°0'0"N 25°30'0"N 25°30'0"N 24°0'0"N 24°0'0"N

Cruise 1

LEG

!. 1

#0 2

0 25 50 100

Nautical Miles 3

Lophelia II Proposed Cruise Tracks

Cruise 1 - Legs 1 and 2

! ! ! ! ! ! ! !

!! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !! ! !!

!!! !!! !!! !!! !!! !!! !!! !!! !!! !!! !!! !!! !!! !!! !!! !!! !!! !!! !!! !!! !!! !!! !!! !! ! ! ! ! ! !

Galveston

Gulfport Pascagoula
14

2.2.2 Cruise 2: RV Brooks McCall and AUV Sentry

The Lophelia II Cruise 2 was conducted on the TDI-BI Ship Brooks McCall from 17 June–1 July, 

2009, and was the second cruise conducted for this contract. The cruise mobilized and embarked 

from Freeport, Texas, and demobilized in Gulfport, Mississippi. The primary objective was to 

conduct exploratory surveys of suspected deep-sea coral communities with the Woods Hole 

Oceanographic Institution (WHOI) AUV Sentry (Figure 2-4). Although beset with equipment 

problems for the first half of the cruise, 5 sites were well documented by the end of the cruise, and 

the final dive at VK826 provided the detailed imaging over detailed bathymetry that forms the 

basis for most of Section4.1 in this report.

Figure 2-4. The AUV Sentry being recovered onto the Research Vessel (R/V) Brooks McCall

following a successful dive.

Table 2-2 lists sites that were occupied during Cruise 2. The cruise track and site locations are 

shown in Figure 2-5. The planned AUV surveys were not completed at targeted features in the 

following lease blocks: GB837, GB535, and GC600.
15

Table 2-2.

Sites Occupied during Cruise 2

Div

e

Site Lat Lon Depth 

m

Photograph

s

Comments

017 test Self-terminate above bottom

018 test 49 Strobe not synched with camera shallow test West 

Flower Gardens

019 GB837 27.1196

7

93.8969

4

865.6 Weight fell off on 3rd line

020 GB837 27.1196

7

93.8969

4

865.6 Camera did not work

021 GB535 27.4311

5

93.5986

1

585.0 691 Phins(INS) inoperable compass substituted

022 GC600 27.3663

9

90.5641

7

1,248.8 Self-terminate above bottom 450 m

023 GC600 27.3663

9

90.5641

7

1,248.8 163 Camera stopped after 10 min.

024 GC246 27.7113

3

90.6760

0

755.0 570 Camera took ~800 pics then quit weight fell at start of 

multibeam

025 MC885 28.0825

0

89.7185

0

3800

Photo-survey complete showing gorgonians and small 

Lophelia colonies. Unprogrammed weight drop before 

multibeam started

026 MC657 28.3436

4

87.9301

0

~2,000 5160

Completed dense mosaic of shipwreck site with 

multibeam data. Ship was clearly and completely 

imaged.

027 MC339 28.6325

1

88.4491

7

1,398.5 ~4000

Completed multibeam and photo survey of mound 

slopes. No problems or delays with vehicle. No coral 

or sea fans noted.

028 VK826 29.1420

0

88.0378

3

610.0 >5000

Completed multibeam and photo survey of most of 

knoll area. All systems functional to end of dive. 

Anticipate good coverage.
16

Figure 2-5. Sites visited, Cruise 2.

!.

!.

!.

!.

!.

!.

!.

!.

!.

!. !.

!.

!.

!.

Gulfport

n

nFreeport

AT47

VK826

MC885

MC339

MC118 MC165

GC852

GC600

GC246

GB837

GB535

GB138

MC 657

GB315 GB225

Texas Louisiana

Mississippi Alabama

Florida

88°30'0"W

88°30'0"W

90°0'0"W

90°0'0"W

91°30'0"W

91°30'0"W

93°0'0"W

93°0'0"W

94°30'0"W

94°30'0"W

96°0'0"W

96°0'0"W 31°30'0"N 31°30'0"N 30°0'0"N 30°0'0"N 28°30'0"N 28°30'0"N 27°0'0"N 27°0'0"N 25°30'0"N

0 15 30 60 90 120

Nautical Miles

Lophelia II - Cruise 2

16 - 30 June 2009

TDI-BI RV BROOKS McCALL

Area 224

±
17

2.2.3 Cruise 3: NOAA Ship Ronald H. Brown and the Jason II ROV

Cruise 3 was completed on NOAA Ship Ronald H. Brown 19 August–12 September 2009. The 

cruise mobilized in Key West, Florida. One mid-cruise personnel transfer took place on 5 

September. The cruise demobilized in Pensacola, Florida, on 12 September 2009.

This cruise employed the ROV Jason II to explore new sites, make a variety of deployments and 

collections, and conduct a variety of studies on natural deep water coral reefs and deep water 

shipwrecks (Figure 2-6). This was a 25-day cruise with 21 ROV dives and an at-sea personnel 

transfer.

Figure 2-6. Illustration of the Jason II/Medea ROV (WHOI).

Jason II was used to: explore 10 new sites (Table 2-3) for the occurrence of deep water coral reefs; 

make collections of Lophelia and other corals for genetic and physiological studies; make 

collections of communities associated with Lophelia and other corals for ecological studies; collect 
18

quantitative digital imagery for characterization of sites and coral communities; collect spatially 

explicit physical near bottom oceanographic data; deploy cameras and microbial arrays; reposition 

larval traps and current meters; collect push cores; and conduct a series of linked archeological/ 

biological investigations on deep water shipwrecks. In addition to launching and recovering Jason

II, elevators were deployed and recovered twice, four moorings (two larval traps and two current 

meters) were deployed, and CTD casts were conducted (Figure 2-7). 

Table 2-3.

Sites Characterized Listed in Chronological Order

Dive Site Dates Times Depth 

m

Lat-D Long-D Comments

J2-

453

Fla Slope18/20-

8/21

2130-

1600 450 26.184100

-

83.292583

J2-

454 DC583 8/22-8/23

1720-

0745 2500 28.385493

-

86.611932

Aborted but dive number 

unchanged

J2-

456 MC294 8/23-8/24

2140-

0745 1360 28.674300

-

87.518917

J2-

457 AT047 8/24-8/25

1630-

0730 863 27.879200

-

88.212217

J2-

458 GC235 25-Aug 1643-2230 530 27.737033

-

90.812733

Aborted: Hydraulic 

Failure

J2-

459 GB299 8/26-8/27

0830-

0740 410 27.692450

-

91.777100

J2-

460 GB535 8/27-8/28

1636-

1216 600 27.422880

-

87.402863

J2-

461 GC852 29-Aug 0118-2020 1400 27.124667

-

90.835833

J2-

462 GC338 30-Aug 0851-2030 900 27.670000

-

89.520320 Aborted: OcTan Failure

J2-

463 Aborted: jelly

J2-

464 MC751 8/31-9/1 1324-1206 460 28.189667

-

88.202167

J2-

465 VK906 9/1-9/2 2031-2000 400 29.069000

-

87.622833

J2-

466 VK826 9/3-9/4 1119-0805 510 29.156933

-

87.989333

J2-

467 VK826

J2-

468 VK786 9/5-9/6 2030-0810 612 29.218833

-

86.223667 Viosca Knoll Wreck

J2-

469 MC657 9/6-9/7 1714-0800 2256 28.343167

-

86.069500 7,000 Foot Wreck

J2-

470 EW1008 9/7-9/8 2025-0830 610 29.142000

-

88.037833 Ewing Bank Wreck

J2-

471 GC245 9/8-9/9 1644-1210 627 27.389500

-

93.600167

Green Lantern

Wreck

J2-

472 MC497 9/9-9/10 2108-0815 554 28.440333

-

88.680000

Gulfpenn

J2-

473 VK906 9/10-9/11

1633-

0815 490 29.065500

-

87.618333

J2-

474 VK826 11-Sep 1259-2312 510 29.156933

-

87.989333
19

Figure 2-7. Lophelia II Cruise 3 track of Ronald H. Brown.
20

2.2.4 Cruise 4: NOAA Ship Ronald H. Brown and the Jason II ROV

This cruise also used the NOAA Ship Ronald H. Brown and was conducted from 13 October– 4 

November 2010. The cruise mobilized in Pensacola, Florida. One mid-cruise personnel transfer 

took place on 24 October. The cruise demobilized in Pensacola, Florida on 5 November 2010.

This cruise employed the ROV Jason II to return to seven of the sites visited with Jason II in 2009 

and explore eight sites not visited during that cruise, including 5 never visited by ROV (Table 2-4, 

Figure 2-8). A variety of deployments and collections were made and both natural deep-water 

coral reefs and deep water shipwrecks. The primary data collected using the ROV included 

SM2000 multibeam, digital video and still photographic imagery, CTD with dissolved oxygen 

(DO) and pH sensors, geological samples, biological samples, archaeological material and push 

cores. Other data streams from the ROVs, such as vehicle attitude, acoustic data, and sonar 

imagery, were recorded by networked computers in the control van. Navigational data for both the 

ship and ROV systems were also recorded. While in transit to and from the site, and during times 

when the ROV is not deployed, Seabeam multibeam bathymetric data were collected. This was a 

21-day cruise with 16 ROV dives and an at-sea personnel transfer.

Table 2-4.

Sites Characterized Listed in Chronological Order

Date Site Dive Number Lat DD Lon DD

10/15/2011 VK826 J2-526 29.158444 -88.016242

10/16/2011 MC885 J2-527 28.066527 -89.713692

10/17/2011 GC246 J2-528 27.689721 -90.644962

10/18/2011 GC354 J2-529 27.597896 -91.826356

10/19/2011 GB299 J2-530 27.684991 -92.220535

10/20/2011 GB535 J2-531 27.421338 -93.595971

10/21/2011 GC140 J2-532 27.811076 -91.53722

10/22/2011 GC249 J2-533 27.737741 -90.521707

10/23/2011 VK906 J2-534 29.068903 -88.377581

10/24/2011

10/25/2011 VK906/862 J2-535 29.068996 -88.376952

10/26/2011 MC751 J2-536 28.193494 -89.798639

10/27/2011 MC796 J2-537 28.161336 -89.752292

10/28/2011

10/29/2011 MC118 J2-538 28.855867 -88.493561

10/30/2011 DC673 J2-539 28.310634 -87.307289

10/31/2011 VK826 J2-540 29.15462 -88.022582

11/1/2011

11/2/2011 MC338 J2-541 28.675076 -88.481303
21

Figure 2-8. Cruise track for Cruise 4 on the NOAA Ship Ronald H. Brown.

2.2.5 Cruise 5: RV Brooks McCall and ROV Kraken II

This cruise used the RV Brooks McCall and was conducted from 14 July– 24 July 2012. The cruise 

mobilized in Freeport Texas and demobilized in Pensacola, Florida on 24 July 2012. This cruise 

employed the ROV Kraken II(Figure 2-9) to collect imagery and samples from three energy 

platforms and one subsea installation (Figure 2-10). Control box cores were also collected 500 m

away from the study platforms when the ROV was not in the water. A combination of bad weather, 

problems with the ROV, and eventually entangling and loosing the ROV at one of the platforms 

prevented achieving all of our objectives during this cruise. However data collected during the 

cruise significantly increased the known depth range for L. pertusa, demonstrated the presence of 

colored morphotypes of L. pertusa in the GoM for the first time, and provided the best data on 

growth and settlement patterns with depth for L. pertusa, which formed the central pieces of a 

paper in submission to Deep Sea Research. At the end of the cruise, after several efforts to obtain 

permission from the platform operators to initiate rescue operations, the ship returned to port 

without the Kraken II . It was eventually recovered several weeks later. Appendix A-1 is the 

Cruise 5 report.
22

Figure 2-9. Kraken II ROV being launched at the Jolliet Platform.

Figure 2-10. Cruise track for Cruise 5.
23

2.3 OVERVIEWS OF SITES VISITED BY ROVS DURING THE TIME PERIOD OF THIS 

PROJECT

The following section describes site characteristics, biological observations and geological settings 

of the dive site locations visited over the course of this project as well as some additional newly 

discovered sites near the site of the Deepwater Horizon spill using techniques developed during 

this project. 

2.3.1 Project Study Sites (Sorted by Depth)

2.3.1.1 GC140 (250 m depth)

GC140 site is a large (3 by 4.5 km with 150 m vertical relief) salt-supported bathymetric high 

centered around 27.81°N, 91.54°W W in about 250 m water depth. This site was dived on twice 

by the SeaEye Falcon ROV and once during the 2010 Ron Brown cruise. One area around marker 

W was mosaicked at this site. Examination of the seismic data revealed several discrete, high 

positive amplitude anomalies, with the highest amplitudes on the north flank and crest. This site is 

geologically related to, but older than the well-studied, deeper "Bush Hill" (GC185) close by to 

the southeast. The subsurface seismic signature at GC140 shows less active migration to the 

seafloor than is present at GC185, but more high positive amplitudes, suggesting thicker, older 

authigenic carbonate. The fault that is "feeding" hydrocarbon to GC185 is antithetic to the larger, 

more deep-seated fault supporting GC140, also suggesting that GC140 is an older seep site. GC140 

was visited briefly by Dr. Harry Roberts in the late 1980's and he reported finding corals, but no 

chemosynthetic communities (aside from a lone tube worm at 280 m). 

The top of this very large feature consists of continuous carbonate outcrops and slabs with large 

furrows between them. Because of the relatively shallow waters of the site (~230 m), there was a 

high concentration of particulates in the water column and relatively high current velocities. There 

were few colonial organisms colonizing the very top of the feature, possibly due to the thin veneer 

of sediment on most of the hard substrata, although anemones and crinoids were occasionally 

present along with numerous fishes, in particular deepbody boarfish and anthiines. In slightly more 

sheltered and high relief areas, extremely large (over 2 x 2 m) colonies of L. glaberrima were 

observed, along with the gorgonian Callogorgia gracilis with Asteroschema sp. (ophiuroid) 

associates and a few other octocorals, including the soft coral Anthomstus sp., which was quite 

common. Although the general appearance of this site, in terms of both geology and the fauna 

present, was reminiscent of the shallow VK862 site, many of the octocoral species (including an 

Atlantic species of Paramuricea) and associates (notably the ophiuroids) were observed only at 

GC140. It should also be noted that L. pertusa., present at VK862, was not observed at GC140. 

The eastern flank of the mound was an extremely steep slope, descending to approximately 360 m 

depth, containing a series of near-vertical cliffs. At the base of many of these sharp features was 

evidence of seepage, including darkly colored sediments, bacterial mats, and an observation of a 

methane bubble stream. An oil slick was also noted at the surface during our survey of this site. 

At 320 m depth, a few isolated tube worms were observed and collected, representing the 

shallowest collection of a tube worm in the GoM, and confirming the previous record for the 

shallowest observations of tube worms in the Gulf. The corals Anthomastus cf. grandiflorus, 

Paramuricea sp. E, Paramuricea sp. H, cf. Echinomuricea sp., Scleracis guadalupensis, 
24

Callogorgia gracilis, Keratoisidinae S1a, Keratoisidinae S1b, Keratoisidinae S1c, and Nicella sp.

were collected from the GC140 site (Appendix A-2).

2.3.1.2 VK 906/862 (320 to 400 m depth)

This site is composed of several discrete areas. The first was identified several years ago from 

BOEM 3D-seismic data and is in the north of VK906 and edge of VK862. The regional area is a 

complex of mounds and depressions superimposed on a large bathymetric high that generally dips 

to the south and is the reflection of a tabular salt body in the very shallow subsurface. The area of 

interest on the top of this regional feature is approximately 4 km X 4 km and ranges in water depth 

from about 320-400 m. The VK906/862 area between 320 and 350 m depth has been visited 

multiple times in the past as part of previous MMS (BOEM) and the United States Geologic Survey 

(USGS) projects. Two areas around markers R and T were mosaicked in this part of the site (in 

VK862). In this area anemones and white Leiopathes sp are very abundant and L. pertusa is also 

present. Large numbers of snowy grouper were present during two previous visits to this area. 

During the 2008 Nancy Foster cruise much more of this site to the south was surveyed by 

multibeam and a dive was made down the side of a canyon running from 380 to 410 m depth. On 

this transect both Callogorgia and L. pertusa were observed, but no large aggregations of either 

were noted. Other colonial cnidarians present in this area included the bamboo coral Acanella and 

Muricedes sp. gorgonians and large numbers of 0.3 m long squid and barrel fish were present in 

this area during the 2008 dive. At the very end of this dive, a mound that appeared to be composed 

primarily of coral and carbonate rubble and was capped by a few small colonies of L. pertusa was 

encountered.

At the southern end of the large salt-supported and seaward-dipping bathymetric feature is a series 

of five small mounds that were identified on a multibeam map constructed from data collected 

during the 2008 NOAA Ship Nancy Foster Cruise. The mounds are roughly 150-300 m in diameter 

with up to 50 m relief above the surrounding seafloor, distributed in roughly a north-south line 

with the largest of the mounds at the southern end of the group. On the 3D-seismic surface 

amplitude maps of the area most of the discrete mounds at the southern end had anomalously low 

positive signatures. Initially, we thought that this seismic response may be related to bubble-phase 

gas in the mounds as a product of seepage around the underlying salt mass. However, after the 

Jason dive on the largest of the southern mounds it became apparent that there was no evidence of 

seepage. A new seismic cross-section through the chain of small mounds clearly indicates that 

there are no direct migration pathways from the deep subsurface to the mounds. Further, they are 

sitting on a hard horizontal reflector that appears to be the surface from which the mounds 

originate. This relationship is unique with regard to all the mounds we have studied on the northern 

Gulf’s continental slope. Seismically, they are similar to the mounds of the pinnacle reef trend of 

the Mississippi and Alabama Outer Continental Shelf (OCS). No carbonates were found on the 

crest of the mound, despite a concerted effort to find and collect a sample rock. To test the 

hypotheses that these mounds in VK906 are L. pertusa reefs that started on subtle relief features 

associated with the hard bottom, a supplemental study was done using gravity cores collected 

through and near the mounds.

A total of 4 dives were made during the Ron Brown cruise in 2009 and 2010 on this southern most 

mound (nicknamed Roberts Reef) with a summit at about 390 m depth at 29.069°N, 88.377°W. A 

total of three areas around markers J, L, and Y were mosaicked on Roberts Reef. The bottom of 
25

the trench to the south of the mound was primarily composed of soft sediment with few organisms 

with a few scattered outcrops that harboring small colonies of L. pertusa, antipatharians, and 

gorgonians (Figure 2-11). The southern-facing base of the main mound structure was confirmed 

to be primarily carbonate and coral rubble and contained some small colonies of live L. pertusa. 

At the base of the mound on every side surveyed there was a moderately high density of glass 

sponges, anemones, and assorted crinoids and sea stars. On the slopes on the E and SW sides of 

the mound this community is joined first by the red form of Leiopathes glaberrima and then later 

L. pertusa at the about 400 m contour. The density of both are higher near the top of the mound 

and over the top of the mound at about 390 m depth L. pertusa is the dominant coral and the white 

form of L. glaberrima largely replaces the red form and covers extensive portions of the sea floor 

(Figure 2-12). The proportion of the substrate covered by live L. pertusa is among the highest 

observed at any site in the Gulf, with the coral forming long swales of standing coral thickets. 

These L. pertusa reefs are apparent on the high-resolution Seabeam multibeam 2000 (SM2K)

bathymetry collected during the second Jason dive at this site. Most of the L. pertusa mounds and 

swales here are covered with live coral and are often covered with small polyps near their terminal 

tips suggesting the corals at this mound could be in a quite active growth phase. Anemones and 

fishes were also very abundant on the top of the mound, including Barrel fish, conger eels, 

Tinselfish, and Beryx.

Figure 2-11. Small colonies of Lophelia, antipatharians, and gorgonians.
26

Figure 2-12. Lophelia and the white form of Leiopathes.

Four other mounds nearby and to the north of Roberts Reef visible on the Nancy Foster multibeam 

maps were also visited. One about 200 m to the SW of Roberts Reef is much smaller and the top 

is at about 440 m depth. Although the substrate at the base of the mound could not be documented,

this mound had very similar fauna as the base of the mound at Roberts Reef, and only a few very 

small colonies of L. pertusa. The next closest mound to the NE of Roberts Reef had lower relief 

and was colonized by scattered anemones, L. glaberimma colonies of a variety of colors, and a 

few small colonies of L. pertusa. Another mound about 600 m to the NNW of Roberts Reef is 

smaller in diameter but rises from a similar depth to a similar height. Fauna on this mound was in 

general very similar to that of Roberts Reef, with a similar depth stratification and changes from 

the base to the crest of the mound. Although overall smaller in size, the percent coverage of 

Lophelia was similar at the crest of this mound. Another mound about 400 m further to the north 

only rises about 10 m from the sea floor, was actually very hard to identify when on the sea floor 

with the ROV and did not have a fauna distinctive from that of the surrounding sea floor other than 

the fact that the density of sea anemones was quite impressive near what was apparently the top of 

this little bump. The corals Nidalia dissidens, Acanthogorgia aspera, Muriceides cf. hirta 1b, 

Muriceides cf. hirta 1c, Paramuricea sp. E, Callogorgia am. americana, and Keratoisidinae S1c

were collected from the VK906/862 site (Appendix A-2).

2.3.1.3 GB299 (340 – 510 m depth)

The GB299 site was identified on a BOEM 3D-seismic amplitude map with a bathymetry 

overlay. It is located at 27.692°N, 91.777°W and the areas of interest range in depth from about 

340 – 410 m depth. The site was visited both during the 2009 and 2010 Ron Brown cruises. Two 
27

areas around markers B and D were mosaicked at this site. This site is situated on NE-SW trending 

oblong structural high, that is 7-10 km across with variable, but often high positive amplitude 

response along the top and on the steep southern flank. The surface of this regional bathymetric 

high is very irregular with discrete ridges and depressions that generally have the same NE-SW 

orientation as the overall feature. The feature is supported by a salt body in the shallow subsurface. 

Above the top of salt the sedimentary section is highly faulted. Although the subsurface beneath 

this local seafloor relief is highly faulted and complex, there are few potential migration pathways 

that show acoustic blanking that could be interpreted as a signature for the presence of gas. 

However, the high amplitude areas along the southern flank of the overall feature were selected as 

the first target areas. The top and the southwest flank were also selected as a target for seafloor 

observations.

Though this site had discrete strong amplitude response coincident with bathymetric highs and 

steep scarps, no large, continuous areas of carbonate substrate were observed, but small carbonate 

cobbles and small pavements were typical of the seafloor. There was very little hard-ground fauna 

on the local topographic high in the area surveyed. The areas of high reflectivity coincided with 

low relief carbonate rubble and pavements with attached gorgonians and antipatharians which 

were scattered over much of the area surveyed on the gently sloping northern portion of the site 

between the depths of 350 and 365 m, and on the ridge to the north between 370 and 390 m. 

Especially impressive at this site was the diversity and overall high abundance of gorgonians and 

antipatharians with associated ophiuroids (Figure 2-13, Figure 2-14). Several of the whole coral 

samples taken that appeared to be growing in mud had authigenic carbonates as their base, buried 

by the mud (Figure 2-15).

Figure 2-13. Carbonate rubble and pavements with attached gorgonians and 

antipatharians.
28

Figure 2-14. Carbonates with corals and sea anemones attached.

Figure 2-15. Corals growing in what appears to be mud, but with carbonate rubble 

underneath
29

At least 3 different species of antipatharians and 4 different species of gorgonians were collected 

along with 5 species of commensal ophiuroids. In addition to the commensal ophiuroids, 

numerous other echinoderms were present in the hard grounds including several different crinoids 

and basket stars. Colonial scleractinians were almost completely absent from the areas surveyed, 

although a single small colony of Lophelia was seen along with the occasional cup coral. This is 

the furthest west site with abundant Leiopathes sp and was sampled extensively for genetics work 

(Figure 2-16). 

Figure 2-16. A colony of the white color-morph of Leiopathes.

The most abundant gorgonian at this site was Callogorgia (potentially more than one species), and 

1000’s of colonies with attached ophioroids were documented. Callogorgia occurred virtually all 

over the site, with the highest density on scattered carbonate rubble along the N facing slope near 

the 365 m contour line (Figure 2-17). 
30

Figure 2-17. Callogorgia spp. colonies with attached ophiuroids.

In one area that was dominated with mottled mud, several half meter wide holes were encountered. 

The bottom of the holes were indeterminate, but in at least one case appeared to be well over a 

meter deep, with fish and shrimp living in and around them (Figure 2-18).. These may have a 

biological origin or may be gas blowout tubes caused by explosive gas release as interpreted for 

similar features at GB201 in 2008. The corals Nidalia dissidens, Muriceides cf. hirta 1a, 

Paramuricea sp. E, Callogorgia am. americana, Keratoisidinae S1b, and Pennatulacea were 

collected from the GB299 site (Appendix A-2).
31

Figure 2-18. Half meter wide holes at GB299.

2.3.1.4 West Florida Slope (400 – 450 m depth)

This area was chosen for study because the bathymetry patterns (hummocky bottom and numerous 

ridges) between about 375 and 500 m depth resembled those of another area 15 km to the north 

where L. pertusa occurrence had been confirmed during Johnson Sea Link (JSL) dives in 2003. 

No 3D-seismic data were available for this area. For this project, the only dive to this area was 

during the 2009 Ron Brown Cruise. This particular site is centered near 26.184°N, 83.292°W and 

depths between 400 and 450 m.

This site had numerous areas of hard grounds ranging from boulders, pavements, linear ridges, to 

long, regional scarps formed by outcropping of resistant sedimentary beds, all likely to be 

exposures of Lower Tertiary carbonates upslope of the Florida Escarpment. At or near the edge of 

the slope, the top of Cretaceous seismic reflector outcrops everywhere along the extent of the 

Escarpment, and this site is upslope of this occurrence. 

Black corals, Leiopathes glaberina, (Figure 2-19) were present in most the areas surveyed, 

although their density was generally low and their distribution patchy. Much more common were 

colonies of Stylaster sp. (Figure 2-20), which ranged in size from about 10 cm to 50 cm in height. 

Although there were many areas apparently suitable for L. pertusa, it was only found in the deeper 

areas of the site we visited. Although there are many possibilities for the lack of L. pertusa above 

about 425 m, it was noted that the temperature in these shallower areas ranged up to 13°C, while 
32

in the areas where L. pertusa (Figure 2-21 and Figure 2-22) was collected temperatures were in 

the 9 – 11°C range.

Figure 2-19. Large Leiopathes colony.

Figure 2-20. Largely unoccupied substrate.
33

Figure 2-21. Lophelia on the West Florida Slope.

The majority of the substantial cnidarian colonies encountered were heavily colonized by crinoids,

and many of them by ophiuroids as well. Most of the exposed carbonates were colonized by 

sponges, although large, potentially habitat forming sponges were rare. Along the shallower ridges 

were much higher density of fishes, including individual tuna, small sharks, Beryx sp., 

Hoplostethus occidentalis, Conger oceanicus, Laemonema spp., and several schools of small 

unidentified fish. Zooplankton swarms were noted along the edge of one of the shallower ridges.

The corals Anthomastus cf. grandiflorus, Anthomastus robustus delta, Aquaumbridae sp. 1a, 

Aquaumbridae sp. 1b, Aquaumbridae sp., Scleraxonian nov sp. 1, Anthothela sp. 2, Acanthogorgia

sp. 1, Acanthogorgia aspera, cf. Muriceopsis sp., Muriceides cf. hirta 1b, Muriceides cf. hirta 1c, 

Muriceides cf. hirta 1d, Paramuricea sp. A, Keratoisidinae S1c, and Plumarella 

pellucida/dichotoma were collected from the West Florida Slope (Appendix A-2).
34

Figure 2-22. L. pertusa on the W. Fl. Slope.

2.3.1.5 MC751 (450 to 465 m depth)

This site was identified using BOEM 3D-seismic surface amplitude/bathymetry data. This site 

was dived upon during 3 ROV cruises as part of this project: with the ROV SeaEye Falcon in 2008 

and on the Ron Brown cruises in 2009 and 2010. Three areas around markers G, H1, and H2 were 

mosaicked at this site.The area of interest is a small oblong feature (about 0.8 to 1.4 km) with 

moderate (20 m) relief feature and moderate to high seafloor amplitude response on seismic maps. 

It is located at 28.19°N, 88.202°W on the southernmost end of a south dipping nose at the 

intersection with a southeast plunging trough created by a down-to-the southwest fault. The fault 

ends at the site at about 450 – 465 m depth. Seismic cross-sections indicate vertical acoustic 

blanking of the record beneath the mound suggesting active gas plumbing up to the site and a

seafloor environment supportive of chemosynthetic communities and corals.

There were a few areas of mottled mud, but an area of about 500 by 500 m was dominated by 

carbonates with relatively clean surfaces. Within this area was an area of about 200 by 200 m with 

a high-density of authigenic carbonate outcrops, slabs, and boulders colonized by Lophelia, 

Callogorgia, and other coral on the tops and Lamellibrachia luymesi tube worms around their

periphery (Figure 2-23). The abundance of live scleractinian corals in the immediate vicinity of 

apparent seepage (both tube worms and bacterial mats in some locations) has not been previously 

observed to the extent that it is found at this site. The other known occurrences of Lophelia at 

relatively active seep sites (such as Bush Hill) consisted of mainly dead coral structure with a few 
35

live polyps at least a few meters away from any tube worms. This site contained live, apparently 

healthy Lophelia growing interspersed with tube worms, and in some cases bacterial mats. A 

variety of fishes, including blackbelly rosefish and morid cods (Laemonema sp.) as well as golden 

crabs, Chaceon fenneri, were relatively abundant at the site.

Figure 2-23. Lophelia pertusa and Lamellibrachia luymesi tube worms.

There was a relatively high diversity of gorgonians at the site as well, including what appeared to 

be multiple species of Paramuricea and a Paragorgia sp. (Figure 2-24). In addition, acesta clams 

were observed at the proximal end of some tube worm tubes, Asteroschema ophiuroids on 

Callogrogia and Paragorgia, and Astrogomphus ophiuroids and coiled gastropods were visible as 

associates on Lophelia. Few black corals were observed, but present were Bathypathes and 

Stichopathes. Icella corals and a large unknown white octocoral were also observed (Figure 2-25).

The corals Paragorgia cf. johnsoni, Paragorgia johnsoni, Muriceides cf. hirta 1b, Paramuricea

sp. E, Swiftia exserta, Callogorgia am. delta, and Cheliodonisis a. mexicana were collected from 

the MC751 site (Appendix A-2).
36

Figure 2-24. Paragorgia sp. coral on right side of image with multiple clonies of 

Paramuricea sp.

Figure 2-25. Lophelia and Callogorgia colonies.
37

2.3.1.6 VK826 (450 – 530 m depth)

Viosca Knoll 826 is a large and quite complex site from a biological perspective. It is located 

around 29.2°N, 88.0°W, with corals in water depths from about 450 to 530 m. There has been a 

great deal of research completed on both the chemosynthetic and deep coral habitats at this site by 

numerous groups over the past 2 decades. This site was dived on multiple times during both Ron 

Brown cruises in 2009 and 2010 and also mapped and photo-surveyed with Sentry during the 

Brooks McCall cruise in 2008. Four areas around markers M, N, O and Q were mosaicked at this 

site. The chemosynthetic communities are concentrated on the SW flank of the mound. These are 

dominated by small tube worm aggregations on the edges of carbonate blocks and areas of 

vesicomyid shell hash. The carbonates are also colonized by a few coral species, mainly 

Callogorgia sp. and a few L. glaberrima and L. pertusa colonies. The SW facing slope of the 

mound progresses from this seep area to higher abundances of L. pertusa on a similar terrain of 

carbonate blocks and low-lying areas of shell hash. The E facing slope has more extensive 

development of L. pertusa reef structures accompanied with L. glaberrima that tend to be on the 

steeper slopes on this side of the mound (Figure 2-26). The coverage of authigenic carbonate 

increases towards to crest of the mound with occasional areas of dense L. pertusa coverage, but 

also an abundance of uncolonized hard substrate. There are also occasional tube worm

aggregations down in the cracks in the carbonates as well as shell hash and occasional bacterial 

mats on soft sediments on the S and W sides of the mound near the crest. Much of the NW corner 

of the mound remains to be surveyed. The NE corner of the mound is similar to the crest, with 

abundant carbonates and scattered L. pertusa thickets interspersed with a few tube worms. 

Figure 2-26. A large mound is colonized by red and orange Leiopathes sp., Eumunida picta, and 

live and dead Lophelia pertusa (VK826).

The newly surveyed peninsula to the E of the main site hosted a very impressive long linear ridge 

of almost continuous L. pertusa colonies over the 500 m surveyed (
38

Figure 2-27). As we approached this ridge from the west, a large school of Beryx splendens 

surrounded the ROV and followed it for over 6 hours (Figure 2-28). On our second visit to this 

site, the same fish surrounded the sub again. It is possible that this is a fairly permanent resident 

population at this site, although future observations are required to confirm this. 

Figure 2-27. Thickets of Lophelia pertusa with Eumunida picta, Echinus urchins, and crinoid 

associates (VK826).

Figure 2-28. School of Beryx splendens over L. pertusa with attached crinoid at VK826.
39

2.3.1.7 GC234 (500 – 550 m depth)

GC234 was a primary study site for both the MMS Chemo II and Lophelia I projects and portions 

of the site have been intensively studied in the past. During this project the site was only visited 

during the 2008 cruise with the ROV SeaEye Falcon. This extensive seep and coral site covers 

several square km and ranges in depth from about 500 to 550 m. The coral area investigated is a 

roughly linear ridge feature running from 27.747o N, 91.224o W at approximately 500 m depth. 

During the Lophelia I project an area of Lophelia pertusa abundance was discovered to the westnorthwest of the main seep site studied during Chemo II. It was a roughly north-south ridge 

colonized by Lophelia pertusa most of which was dead standing coral. In between the seep site 

and the coral ridge is an area of small carbonate boulders colonized by the gorgonians Callogorgia 

americana delta. A multibeam survey revealed an unexplored linear ridge running north from the 

explored area in the GC234 lease block into the GC190 lease block, and rising from 500 to 450 m. 

Exploration of this ridge revealed additional carbonate outcrops colonized by Lophelia pertusa 

and Callogorgia americana, including some approximately 3 m high and 3-4 m in diameter, 

consisting of mainly dead Lophelia and high abundances of fishes including Hoplostethus sp, 

Urophycis sp., Tinsel fish, and conger eels (

Figure 2-29). Other outcrops harbored scattered colonies of a diversity of cnidarians including 

bamboo corals and gorgonian genera including Paragorgia, Muricea, Scleracis, Thesea ,and 

Paramuricea (Figure 2-30). Unfortunately, collections were not possible for most of this dive, so 

further identification was not possible. The corals Scleraxonian nov sp. 1, Paragorgia cf. johnsoni, 

Acanthogorgia aspera, Muriceides cf. hirta 1b, Paramuricea sp. A, Callogorgia am. delta, and 

Cheliodonisis a. mexicana were collected from the VK826 site (Appendix A-2).

Figure 2-29. Dead Lophelia accumulation with Hoplostethus sp.
40

Figure 2-30. Callogorgia sp. and Asteroschema sp. along with some small cup corals.

2.3.1.8 GB535 (515 – 540 m depth)

L. pertusa was sighted here during the last few minutes of a JSL dive in 2003 and was dived on 

during both the 2009 and 2010 Ron Brown expeditions as part of this project. Two areas around 

markers C and E were mosaicked at this site.The site is located at 27.42°N, 93.60°W in between 

515 and 540 m water depth. Examination of BOEM 3D-seismic data and bathymetry suggested 

the presence of hard grounds and the potential for other areas with Lophelia in this immediate area. 

Though the very steep slope of the scarp shows little amplitude variation on the seismic data, high 

reflectivity on the top of the slope suggested the presence of carbonate hard ground substrates on 

the top of the slope.

Multibeam bathymetry data acquired during the Nancy Foster cruise in 2008 with the Sentry AUV 

identified a large area of fluidized sediment expulsion and several smaller features that also may 

represent centers for more localized flows. The AUV multibeam data clearly define nearconcentric ridges on the surface of this large domal feature, strongly suggesting fluidized sediment 

expulsion from a point of origin (vent) located toward the southwestern end of this broad area. 

Photographs from the 2008 Sentry survey found no exposed carbonates or corals on the surface of 

this broad area, but white material interpreted as Beggiatoa and evidence of brine seepage were 

common. Pockmarks, suggesting the rapid release of gas, are typical of the area as well. The data 

also defined a long ridge of about 50 m relief and small bathymetric features associated with the 

upper edge of the ridge. Seismic data clearly define this scarp as a fault. The top of this fault with 

its small mound-like features was the area chosen for investigation.
41

The substrate near the base of the down-to-the-northwest fault scarp was almost entirely composed 

of mottled mud with minor carbonate rubble. The steep slope of the fault scarp had a few carbonate 

cobbles and some areas of rubble, but was primarily mottled mud. The top of the scarp had 

common carbonate rubble, pavement, and occasional small and large boulders. On the gentle slope

past the top of the scarp, seep related features and organisms were observed on pavement and small 

boulders. These localized communities appear to be responding to seepage along a family of small 

faults that are "splinters" off the main down-to-the-northwest fault.

Carbonate rubble, pavement and occasional boulders were present close to the ridge crest along 

the entire length of the ridge surveyed. The most abundant macrofauna on this rubble were white 

sponges (Figure 2-31). 

Figure 2-31. White sponges.

The orange antipatharian whip corals, Stichopathes sp, and three octocorals, Narella sp. Nicella

sp., and Scleracis sp were patchily distributed on carbonate rubble and on the boulders (Figure 

2-32). Additionally, Lophelia colonies were present along much of the top of the slope of the ridge 

and along its crest (Figure 2-33). Colonies of live Lophelia ranged from very small colonies 

consisting of less than 20 polyps to mounds of Lophelia framework several meters in diameter and 

two m high covered with live Lophelia. In one area the entire slope below a pair of mounds was 

scattered with Lophelia rubble suggesting a long history of Lophelia growth here (Figure 2-34).

The corals Stoloniferan sp. 1, Anthothela nov sp. 1, Acanthogorgia aspera, Muriceides cf. hirta

1a, Muriceides cf. hirta 1b, Muriceides cf. hirta 1d, Paramuricea sp. A, Cheliodonisis a. mexicana, 

and Paracalyptrophora carinata were collected from the GB535 site (Appendix A-2).
42

Figure 2-32. Patchily distributed fauna on carbonate rubble.

Figure 2-33. Lophelia colonies.
43

Figure 2-34. L. pertusa rubble.

2.3.1.9 GC235 (520 m depth)

The GC235 site was identified on BOEM 3D-seismic surface amplitude data superimposed on 

bathymetry. This site was only visited during a single dive during the 2009 Ron Brown cruise. 

The feature of interest is a roughly circular, low-relief platform with little small-scale relief 

covered by a “bright spot” of high positive reflectivity on the surface amplitude map. It is located 

at 27.737°N, 90.813°W in ~520 m of water. Around the northern, western, and southern flanks of 

the platform very-low-surface-amplitude response and vertical zones of acoustic blanking on 

seismic cross-sections was interpreted to be related to higher-flux zones of seepage. The seismic 

data suggested that the top of the platform would have abundant hard-bottom areas and more 

scattered hard grounds would be characteristic of the apparent higher-flux zones along the 

northern, western, and southern flanks of the feature. 

However, the central area of this site, over the areas of highest reflectivity, consisted of plain 

sediments, largely uninhabited by visible fauna. No authigenic carbonate hard grounds were 

encountered associated with top of the platform, which was sediment covered and largely 

uninhabited by visible fauna. Around the periphery of the area of reflectivity were sediments with 

limited indications of seepage with occasional bacterial mats and some frenulate siboglinids 

(pogonophorans). Small boulders were found to the southwest where the amplitude anomalies 

appear weaker and much smaller, similar to the seismic character at GC234 where corals were 

found. Some of the exposed authigenic carbonates were colonized by megafauna. One large, 2-3 

m high and 2-3 m wide boulder, and a few smaller carbonates were entirely colonized by the 

vestimentiferans Lamellibrachia luymesi and Seepiophila jonesi (Figure 2-35). Slightly north and 

east of this large tube worm aggregation were a number of small, low-lying carbonates colonized 
44

by primnoid gorgonians (some Callogorgia spp.), cup corals, and individual tube worms (Figure 

2-36). The coral Callogorgia am. delta was collected from the GC235 site (Appendix A-2).

Although it is likely that the majority of the exposed carbonates in this area were explored (based 

on the ROV-mounted sonar), Jason developed a hydraulic leak before we could finish a more 

thorough survey and the dive was terminated. 

Figure 2-35. Vestimentiferans Lamellibrachia luymesi and Seepiophila jonesi.

Figure 2-36. Primnoid gorgonians at GC235.
45

2.3.1.10 GC354 (525 m depth)

The GC354 site was one of the primary sites in the Lophelia I project, and was explored on a series 

of dives on both NOAA Office of Ocean Exploration (OER) and National Science Foundation 

(NSF)-funded seep cruises in the early 2000s. As part of this project it was dived on during the 

2010 Ron Brown cruise. One area around marker V was mosaicked at this site.The site lies near 

27.56°N, 91.82°Won the top and flank of a large mound. The top of the mound, at approximately 

525 m depth, contains a series of small L. pertusa. coral mounds composed mainly of dead coral 

framework on large boulders with small accumulations of live coral at the tops. Large sponges are 

also common on these large boulders, and many of them supported aggregations of Hoplostethus

fish. On the flank of the mound are boulders and low-lying carbonate outcrops containing a 

relatively high diversity of octocorals (Acanthogorgia, Muricedes, Nicella, Paracalptophora) and 

antipatharians (Stichopathes) with a suite of associates, mainly galatheid crabs. At the base of the 

slope, approximately 580 m depth, is an area of more active seepage with large flat carbonate 

blocks and tube worms around the edges where there are seepage conduits. The corals 

Acanthogorgia aspera, Muriceides cf. hirta 1a, Muriceides sp. 3, Paramuricea sp. A, Swiftia 

exserta, Cheliodonisis a. mexicana, and Paracalyptrophora carinata were collected from the 

GC354 site (Appendix A-2).

2.3.1.11 GB201 (525 m depth)

GB201 is a large (~6.5 km by 5.5 km, 250 m high) seafloor structure supported by a shallow salt 

diapir rising to about 525 m depth located at 27.790oN, 92.743oW. This site was first surveyed by 

Harry Roberts on an exploratory dive in 1997, during which he noted the presence of corals. During 

this project, this site was only visited during the 2008 cruise with the ROV SeaEye Falcon. 3-D 

seismic amplitude extraction of the seafloor reflector shows several areas with anomalously high 

positive amplitudes suggesting hard ground development on the seafloor potentially conducive to 

coral habitat. The northwestern flank and several discreet areas on and near the crest showed the 

most promise for coral habitat and were chosen for the dive. One characteristic of this feature is 

the abundance of “pockmarks”, circular depressions on the seafloor that are hypothesized to be 

strong flows of gas without brine or sediment that excavated sediment from the area, as opposed 

to constructional mud volcanoes and flows that introduce new sediments to the area. There was 

very limited colonial coral development discovered at this site. Most of the area surveyed 

consisted of soft bottom with occasional colonial soft coral or hydroid colonies (Figure 2-37). One 

area with bacterial mats and methane bubbling from the seafloor immediately adjacent to tube 

worms was encountered. In another area a single large black coral (Figure 2-38) and a few

Callorgia sp. octocorals were observed. Very little megafauna were found in the areas with pockmarks and the low seismic return was consistent with a general absence of hard grounds in these 

areas of the site. It is possible that the sediment ejected from the numerous pockmarks effectively 

covered the high-return areas identified in the seismic data with a layer of sediment, thus making 

them unavailable for coral settlement and growth. 
46

Figure 2-37. A small octocoral colony in GB201. Note the high concentration of 

particulates in the water.

Figure 2-38. The large black coral at GB201.
47

2.3.1.12 EW1009 (560 m depth)

The EW1009 seep site is ~9 km from the ship wreck in EW1008 at a depth of about 560 m. This 

site was only visited during the 2008 cruise with the ROV SeaEye Falcon. The area of interest is 

relatively small compared to most the sites targeted for the coral exploration (500 m by 2 km). The 

primary target at the northern end of the overall site was ~500 m by 600 m, with 20 m vertical 

relief, and shows moderately high positive amplitude response. The southern two-thirds of the site 

exhibits low relief and has a prominent pockmark on the eastern side. A single very short dive to 

EW1009 was conducted without the ultra-short baseline (USBL) navigational system or the 

compass due to ROV and USBL failures. Additional ROV problems were encountered on the sea 

floor and only the landing site and a small area immediately around the ROV “garage” was 

surveyed. The bottom appeared to be soft sediment, but the sediment may have been overlying a 

thin carbonate crust since there was very little disturbance of the bottom when the ROV landed. 

No high relief features were seen in a 360° sonar scan of the immediate area. 

2.3.1.13 MC539 (630 m depth)

The MC539 site is a small mound (~300 by 250 m with ~20 m vertical relief) at 28.413oN,

89.402oW in about 630 m depth that was identified using 3-D seismic data. It was selected from 

the list due to its proximity to the Gulfpenn wreck and two production platforms in adjacent lease 

blocks. This site was only visited during the 2008 cruise with the ROV SeaEye Falcon. The 

amplitude extraction from the site shows a strong positive response indicating a hard seafloor 

(authigenic carbonate). The seismic cross-sections across the mound show a vertical acoustic 

wipeout suggesting active gas migration to the seafloor, providing a source for seepage and 

therefore authigenic carbonate production. The only dive at this site experienced telemetry and 

video signal problems and was terminated shortly after reaching the sea floor in the center of the 

feature identified on the 3-d seismic map. Only soft bottom was seen during the brief visit to this 

site.

2.3.1.14 MC885 (650 m depth)

The MC885 site was visited during the Lophelia I project, and is a known site of chemosynthetic 

activity that was visited during a series of NOAA OER cruises in the early 2000s (Cordes et al. 

2007). The multibeam acquired during the 2008 Nancy Foster cruise revealed an additional mound 

with a very similar appearance to the explored area of the site, and a series of smaller mounds to 

the south. The mound located approximately 1 km to the east of the known site is a circular 

bathymetric high (1.3 by 1.3 km, with up to 30 m of vertical relief) with moderately high positive 

seafloor amplitude response from 3-D sesmic data. The exploratory site and the previously visited 

site are on a large salt supported bathymetric high (3 by 4 km). This site shows clear indications 

of vertical gas migration on vertical seismic cross-sections.

Our surveys during the 2010 cruise first relocated some of the markers and areas surveyed during 

Lophelia I on the western mound centered at approximately 28.65oN 89.71oW and 620 m depth. 

This area contained scattered Lophelia colonies of fairly small size interspersed with Callogorgia 

americana delta. There were also some larger locations with Madrepora oculata growth, making 
48

this the only site in the northern Gulf where these two species of scleractinians are known to cooccur (they also co-occur on the Florida platform). Catshark eggcases were frequently observed 

on the Callogorgia americana delta colonies, as had been observed in previous years. This appears 

to be a persistent location for the depositing of egg cases on the gorgonian colonies. The eastern 

mound, centered at approximately 28.62 N, 89.69 W and at 620 m depth, appeared to be more 

active, exhibiting numerous signs of seepage, including stained sediments and apparently live 

clams. Callogorgia americana delta along with Asteroschema associates were also present on the 

eastern mound, often interspersed with tube worms (Figure 2-39) but no other corals were observed 

during our short survey of this area. The coral Callogorgia am. delta was collected from the 

MC885 site (Appendix A-2).

Figure 2-39. Typical setting at MC885, including small tube worm aggregations and occasional 

colonies of Callogorgia americana delta.

2.3.1.15 GC246 (770 – 860 m depth)

This site was targeted for investigation during the first (2008) ROV cruise with the SeaEye Falcon

DR ROV but problems with ROV prevented a dive during that cruise. However, bathymetry 

collected during that cruise was used to plan the single dive accomplished during the 2010 Ron 

Brown cruise. The GC246 site is a large (5 km by 6 km, 100 m vertical relief) salt supported feature 

with a steep eastern flank and a gradual western flank with the northern edge at 27.6897°N, 

90.645°W and features of interest at depth from 770 to 860 m. Five discreet bathymetric highs 

with positive amplitude responses are aligned roughly north-south along the eastern flank of the 

top of the feature, all with interpreted sediment flows present down the eastern flank (characterized 
49

by high amplitudes, presumably due to coarse sediment flowing out of the active seep sites and/or 

lithification of hydrocarbon saturated sediment). The discreet seismic highs located on local 

bathymetric highs were targeted because of their potential to host hard grounds appropriate for 

coral settlement. This site was thoroughly explored by Jason during a 16 hr dive. Most of the site 

was soft sediment and several areas of active seepage were found, including a small brine lake, 

mud volcanoes and areas with mussels and bacterial mats(Figure 2-40). A series of small exposed 

carbonates harboring Callogorgia sp. and symbiotic ophiuroids were present near 27°69°N, 

90.645°W at 845 m depth. The corals Paramuricea sp. B3 and Callogorgia am. delta were 

collected from the GC246 site (Appendix A-2).

Figure 2-40. A dense field of dead Bathymodiolus mussels with disarticulated shells (GC246).

2.3.1.16 GC249 (780 - 820 m depth)

GC249 contained a fairly large high-amplitude anomaly that sites at the top of a local bathymetric 

high. This site, at about 27.72°N, 90.51oW had never been visited before and the multibeam map 

used to guide the dive was acquired immediately before the single 2010 Jason dive. A total of 8 

hours was spent surveying this site between 780 and 812 m depth. Most of the site was soft bottom 

despite the high reflectivity indicated in the seismic maps used to select the site for investigation. 

Several seep areas were encountered (Figure 2-41). Most common were areas that were dominated 

by shell hash and bacterial mats with a few Callogorgia attached to the consolidated hash. Two 

areas were encountered with live mussels and one of these also had tube worms associated with 

small carbonate outcrops. This site is just to the east of the GC246 site, and to the southeast of the 

known seep site in GC204, and may represent a continuation of these fluid flux features. The coral 

Callogorgia am. delta was collected from the GC246 site (Appendix A-2).
50

Figure 2-41. Bacterial mats and purple ciliates cover a number of Lamellibrachia luymesi tube 

worms and Bathymodiolus childressi mussels (GC249).

2.3.1.17 AT47 (835 - 860 m depth)

The feature investigated in AT47 is one of several low relief complexly mounded areas east of the 

southern end of the Mississippi Canyon where the canyon transitions into the Mississippi Fan. The 

site is located at 27.88°N, 89.79°W in about 835 - 860 m depth. The only dive to this area was 

during the 2009 Ron Brown Cruise. One area around marker A was mosaicked at this site. Like 

the productive dive sites in AT 340 visited during the 2006 and 2007 Chemo III cruises, this site is 

characterized by numerous low relief mounds and shallow depressions. The AT47 site was 

identified on BOEM 3D- seismic data processed to display reflectivity (amplitude) of the seafloor 

and configuration of the subsurface related to conduits for fluid and gas migration. Geologically 

this area constitutes a broad structural nose plunging to the south and supported in the subsurface 

by salt. The mounds and shallow depressions defined by bathymetry have distinct high and low 

positive amplitude signatures, suggesting localized areas of relatively hard and soft bottom. The 

areas of high positive amplitude link to faults and other clear migration pathways from the flanks 

and top of salt as indicated on seismic cross sections. Multibeam bathymetry collected during the 

first cruise of this project on the NOAA Ship Nancy Foster revealed numerous areas with narrow 

ridges and apparent small mounds of a few meters relief suggestive of possible coral habitat.

Most of the AT47 area that exhibited high positive amplitude on the 3D-seismic data had no 

carbonate hard grounds exposed at the seafloor. However, there were clear signs of seepage 

everywhere, including patches of dark reducing sediment, localized brine flows, and white 
51

bacterial mats. The high seismic reflectivity or high positive amplitude of the seafloor reflector 

appears to be related to the extensive and dense clam beds which covered large areas defined by 

high surface reflectivity on 3D-seismic data (Figure 2-42). The gross majority of the intact clamshells that were clearly visible were Calyptogena ponderosa. This field identification was 

confirmed with the collection of a live C. ponderosa, one of the only apparently live clams seen 

during the dive. Brine seeps were scattered throughout the clam beds. Some supported dense, but 

limited living mussel communities (Figure 2-43). Not only did the shell beds cover large expanses 

of the sea floor, but on some slopes the beds appeared to be at least several layers thick. There 

were no colonial corals associated with the clam or mussel beds.

Figure 2-42. Extensive and dense clam beds.
52

Figure 2-43. Articulated and disarticulated clam shells with some live mussels.

Carbonate pavement may underlie some of the bivalve beds, as the Jason was unable to penetrate 

more a few inches with a pushcore associated with one bed. The highly reflective sites that 

supported densely populated clam beds occurred on lobate features that extend generally to the 

south. These may have been old mudflows that have been vertically displaced by the upward 

movement of shallow subsurface salt. Such movement would have activated local faults that acted 

as conduits for fluid and gas migration to the modern seafloor supporting a slow seepage 

environment.

The major exception with respect to coral occurrence was in the southern-most area surveyed, and 

encountered at the very beginning of the dive. In this area, there was a thin cover of clam shells 

and live mussels on the lower portions of the slope near a Madrepora community, with steadily 

increasing areas of dead scleractinian coral rubble and small mounds of dead coral as we moved 

upslope (Figure 2-44). Also notable in this area were numerous golden crabs, often associated 

with areas of dead coral. Numerous colonies of Paramuricea gorgonians were seen attached either 

to the clam or coral rubble. Even here there was very little if any visible carbonate. Near the apex 

of this slope, a single large, mini-van size, mound of dead Madrepora was encountered (Figure 

2-45), with several areas of live coral present on the top and edges of this mound. Also present on 

the mound were attached gorgonians and at least 4 golden crabs (Chaceon). Although this area 

was impressive for the quantity of dead coral and clam shells, it was apparently of limited extent, 

less than about 50 m on a side. The abundance of coral rubble and clam shells on the slopes below 

the Madrepora mound suggest this site may have hosted coral and clams for at least hundreds to 

thousands of years. The corals Paramuricea sp. B3 and Swiftia cf. koreni were collected from the 

AT047 site (Appendix A-2).
53

Figure 2-44. Large standing colony of Madrepora.

Figure 2-45. Dead Madrepora, areas of live coral and golden crabs (Chaceon).
54

2.3.1.18 MC118 (880 m depth)

MV118 is also known as the (Ole Miss) Hydrate Observatory Site. The site is clearly visible 

on 3D seismic maps of the region with the most intense reflectivity within a 100-mile radius. 

The site is located at 28.85°N, 88.5°W in about 880 m depth. This site has been well mapped 

by AUV and numerous ROV and JSL dives since 2005 and numerous geophysical, geochemical 

and microbiological instruments are on the sea floor. This site had not been well studied by 

macrobiologists although in addition to active seeps, hydrates, and seep communities the 

site hosts several areas with extensive development of colonial corals. We dived on this site 

one time as part of this project, during the 2010 Ron Brown cruise. One area around markers 

T1 and T2 was mosaicked at this site.

The dominant gorgonian at this site was Paramuricea sp. This gorgonian was found attached 

to carbonate boulders in numerous locations throughout the site, and in some areas was 

present as quite large (and old) colonies in relatively high densities (Figure 2-46). Most of the 

colonies of Paramuricea encountered hosted commensal ophiuroids. Three areas with live 

colonies of the hard coral Madropora sp. are also present at this site, one of which had more 

living Madropora present than any other site visited as part of this program. Chrysogorgia 

sp. was rare but present at the site and small crabs and anemones were often associated with 

this coral. Golden crabs (Chaceon fenneri) were abundant at this site and present at elevated 

densities in association with both living and dead Madropora thickets. The corals 

Paramuricea biscaya B2, Paramuricea sp. B3, and Chrysogorgia sp. 1b were collected from 

the MC118 site (Appendix A-2). 

Figure 2-46. A single large colony of Paramuricea sp. is seen along with a number of its 

associated Astroschema sp. (MC118).
55

2.3.1.19 GC338 Site Summary (900 m depth)

The GC338 site was chosen because of areas with discrete high positive amplitudes on the seismic 

interpretation and an east-west trending ridge representing a local bathymetric high. The site is 

located at 27.67°N, 89.52°W in about 900 m depth. The site was dived on once during the Ron 

Brown 2009 cruise and the multibeam bathymetry necessary to plan the dive was acquired 

immediately prior to the dive. The relatively short single dive was aborted prematurely due to an 

octans failure on the ROV.

The only area visited with significant coverage of colonial cnidarians was on the southern flank of 

the ridge slightly downslope of the local topographic high. In this area there were beds of 

disarticulated vesicomyid shells (primarily Calyptogena ponderosa) on the slope with variable 

amounts of carbonate from scattered rubble (Figure 2-47), to pavement and small boulders. On

the carbonate were scattered colonies of Callogorgia sp. with attached ophiuroids and a few 

colonies of other corals including Chrysogorgia sp., Bathypathes sp., and Paramuricea sp. (Figure 

2-48 and Figure 2-49). On the top and N and E flanks of the ridge the seafloor was composed 

almost entirely of mottled mud and although there were numerous burrows present, very little 

benthic fauna was noted. Discrete areas of brine seepage and bacterial mat were encountered to 

the southeast. The corals Clavularia rudis, Muriceides sp. 2, Paramuricea sp. B3, Callogorgia 

am. delta, and Chrysogorgia sp. 1b were collected from the GC338 site (Appendix A-2). 

Figure 2-47. Carbonate rubble and clam shells scattered over the seafloor.
56

Figure 2-48. Callogorgia with attached ophiuroids.

Figure 2-49. Paramuricea with attached ophiuroids.
57

2.3.1.20 MC294 Site I (1350 – 1400 m depth)

The MC294 site was discovered and evaluated using BOEM 3D-seismic data. It is characterized 

by a series of structural highs and lows along a regional northwest-southeast ridge at a depth of 

approximately 1400 m. Note that this is part of the same feature later investigated as part of the 

MC338/294 coral sites discovered one year later. The dive to the area described here was made 

during the 2009 Ron Brown cruise. The area chosen for evaluation during the 2009 Ron Brown

cruise at 28.674°N, 87.519°W and 1360 m depth had anomalously high positive amplitude 

response on the seismic data. 

The high positive reflectivity on the 3D-seismic suggesting the presence of hard grounds on an 

elevated ridge was confirmed only in one small area where a pavement of authigenic carbonate 

was encountered covered with a fine layer of mud (Figure 2-50). This site primarily contained 

relatively featureless sediment, with some evidence for seepage in a few areas. The northern 

section of the 2 km long ridge contained some isolated patches of stained sediments, bacterial 

mats, and a few areas of authigenic carbonate pavements. It is likely that carbonate was present at 

all the seismic anomaly targets, but covered by sediment.

Figure 2-50. Sporadic bacterial mats at MC294.
58

In some areas where the pavement was fractured, it was colonized by small tube worms and a few 

small tube worm aggregations (Figure 2-51) along with some seep-related galatheids. There was 

also one area with dead mussel shells and a small bed of live mussels. There were at least 10 

species of fishes encountered at this site as well as a few different species of shrimp and crabs. 

Overall biological megafaunal density and diversity was quite low, and there were no corals 

observed at all during the dive. The corals Clavularia rudis 1a, Stoloniferan sp. 2, Paragorgia 

regalis, Acanthogorgia aspera, Paramuricea biscaya B1, Paramuricea biscaya B1a, Paramuricea 

biscaya B2, and Swiftia pallida were collected from the MC294 site (Appendix A-2).

Figure 2-51. Small tube worm aggregations at MC294.

2.3.1.21 MC388/294 (1370 – 1800 m depth)

The last dive of the Ron Brown 2010 cruise was an exploratory dive to the northern end of MC388 

and southern end of MC294. The main coral area around marker AA was mosaicked at this site. 

The site was chosen because of numerous high reflectance areas along a northward tending ridge 

in block 338. Only soft sediment with occasional discolored sediment was seen at the southern 

end of this ridge near 28.648°N 88.467°W in 1800 m water depth. No carbonates or significant 

sonar targets were encountered until about 6 hours into the dive when a single Madropora colony 

on a carbonate boulder at 28.67°N, 88.47°W in 1,370 m depth was discovered. About 400 m to 

the north another sonar target led to the discovery of several carbonate boulders colonized by 

numerous gorgonian corals and other fauna. Many of the corals at the site were partially or 

completely covered in a brown flocculent material and the ophiuruids on the corals were exhibiting 
59

abnormal coloration and behavior (White et al. 2012). Analysis of the material on the corals 

detected hydrocarbons that were later fingerprinted to the Macondo well (White et al., 2012). 

This site has subsequently been visited 6 times and the coral colonies in the central portion of the 

site (Figure 2-52) have been monitored for potential recovery from the initial impact from the spill. 

The dominant colonial coral at this site is Paramuricea biscaya (Grasshoff 1977), a gorgonian 

with planar arborescence morphology (Figure 2-53). Over the course of all visits we have digitized 

images of 51 live or recently living P. biscaya colonies and categorized the branches of the 

colonies into three categories: 1) branches with obvious and significant visible impact in the form 

of coverage by floc (White et al. 2012), excess mucous production, obvious tissue damage, or bare 

skeleton 2) branches clearly colonized by hydroids; and 3) branches without these forms of 

obvious visible impact. There were a total of 17 commensal Harmathoid anemones documented 

on 13 P. biscaya and one S. palida at this site. Forty-one of the P. biscaya had at least one 

Asterschema clavigerum ophiuroid attached during at least one visit. There were 5 other colonial 

octocorals at the site in addition to the P. biscaya: One large Paragorgia regalis (Nutting 1912), 

two Swiftia pallida (Madsen 1970), one Acanthogorgia aspera (Pourtalès 1867) and a small area 

of carbonate encrusted with Clavularia rudis (Verrill 1922). A manuscript summarizing the 

changes through October 2011 was published in Proceedings National Academy of Sciences 

(PNAS) December 11, 2012:109(50) 20303–20308. (Appendix C-4). The corals Clavularia rudis

1a, Clavularia rudis, Stoloniferan sp. 2, Paragorgia regalis, Acanthogorgia aspera, Paramuricea 

biscaya B1, Paramuricea biscaya B1a, Paramuricea biscaya B2, Swiftia pallida, and 

Keratoisidinae I2 were collected from the MC388/294 sites (Appendix A-2). 
60

Figure 2-52. Photomosaic of the central area at MC294/338 with each coral identified for 

monitoring.
61

Figure 2-53. Example of a coral (A10) imaged during 6 different visits to the MC338/294 site.

2.3.1.22 GC852 (1400 m depth)

The GC852 site was originally identified on BOEM 3D-seismic data which defined it as a 

prominent N-S trending ridge supported by salt in the shallow subsurface. The ridge is ~15 km 

long, 5 km wide, with up to 200 m relief, and it resides in ~ 1400 m of water. Discrete strong 

positive amplitudes are present along the top and flanks of the feature. This site was chosen for 

the Chemo III project and extensive seep and hard ground areas were verified during that program 

using camera sled, Jason, and Alvin. A high quality bathymetric map of the site was also acquired 

with C&C Technology's Hugin AUV using an onboard multibeam system. Higher resolution 

multibeam bathymetry maps were made over selected areas with SM 2000 mounted on Jason. The 

Hugin AUV data define the overall site as a elongate ridge with considerable small scale 

topography on top. During a 2006 Alvin dive in support of the Chemo III project, the highest part 

of the ridge at 27.125°N, 90.836°W and 1400 m deep was found to support a thriving coral 

community. The southern end and the highest part of the ridge were the focal points of prior visits 

to GC852 associated with the Chemo III project.

A single dive was made to this site during the 2009 Ron Brown cruise as part of the present project. 

The top of the ridge is covered with large boulders and outcrops of hydrocarbon and seep-related 

authigenic carbonate. The central part of the top of the ridge is 20-30 m deeper than the shallowest 

south-central part that supports the coral community discovered during the Chemo III project. This 

central part is sediment covered and has less exposures of carbonate and fewer corals. 

There is a single moderately large area of coral colonization that was nicknamed “Coral Gardens” 

during the Chemo II project that although dominated by bamboo corals, had a high diversity of 

colonial corals. Present in this area are Iridigorgia sp. colonies as well as Corallium sp., 

Paramaruricea sp., Bathypathes sp. In one area the boulders were extensively colonized by a 

purple alcyonacean. Two portions of this area were colonized by the scleractinian corals 

Madrepora oculata, Solenosmilia variabilis, and Enallopsamia rostrata (Figure 2-54 and Figure 

2-55). 
62

Figure 2-54. Coral colonization at central part of GC852.

Figure 2-55. Iridogorgia and bamboo corals at the central portion of the site.
63

On the northern end of the ridge are very steep slopes of sediments that appeared to be too unstable 

to support coral communities (Figure 2-56). At the base of this slope were a few isolated mussel 

beds. At the tops of the bathymetric highs on the northern end of the ridge were a few isolated 

octocoral colonies (Figure 2-57). The center of the ridge was also primarily soft sediments and 

was devoid of corals as well. The corals Clavularia rudis 1b, Corallium sp. 1, Paramuricea 

biscaya B2, Swiftia pallida, Iridogorgia splendens, Keratoisidinae I1, Keratoisidinae I2, and 

Narellla pauciflora were collected from the GC852 site (Appendix A-2). 

Figure 2-56. Steep slope on the flank of the northern end of the GC852 site.

Figure 2-57. Isolated octocoral colonies at northern end of GC852.
64

2.3.1.23 DC583 (2,200 – 2,500 m depth)

The GC852 site was identified on BOEM 3D-seismic data using bathymetric contours with 

seafloor amplitude underlay. The only dive to this area was during the 2009 Ron Brown Cruise. 

The area of investigated is located at the northwestern end of the Florida Escarpment. Targets near 

the base of the Escarpment in ~2,500 m of water were investigated followed by a transit up the 

steep slope, and survey along the break in slope of the Escarpment at a depth of ~2,200 m. The 

first target at this site was an oval shaped mound at 28°23.11’N, 87°23.28’W bounded on the 

northwest and southeast by faults, as indicated on seismic cross sections. There was moderately 

positive amplitude response on the top and upper flanks of the mound. The mound was covered 

with very light colored sediment on the top (a thin veneer on top of rock?), with two 6-8 m diameter 

pockmarks with accumulations of pteropod shells at the summit and extensive outcrops of highly 

indurated rocks on the flanks.

The outcrops were generally massive, non-bedded, and made up of dense, dark brown to black 

rock – no sedimentary bedding was observed. The surface of several of the outcrops had pillow 

structures reminiscent of basaltic lava and many had large fissures 10's of m long, 1 meter wide, 

and 5-10 m deep. There were a few outcrops that appeared to be 2-3 flows stacked on top of each 

other and extending 10's m. The relief on the fault faces was up to 25 m high and near vertical (in 

places there were overhangs). These outcrops were colonized by at least two genera of bamboo 

corals (one branched and one unbranched), one antipatharian and one bubble gum coral 

(Paragorgia sp). These were moderately abundant on the E and N sides of the mound. On the W 

and S sides of the mound, there were sparse octocoral colonies at the top and scattered tube worm

(Escarpia laminata and Lamellibrachia sp.) aggregations closer to the base (Figure 2-58). 

Keratoisis sp. bamboo corals were common and relatively large, up to 1 m. Lepidisis sp. and 

Isidella sp. were present but rare. 

Figure 2-58. Tubeworms near the base of the outcrop.
65

The single observation of Isidella marks a depth record for this genus in the Gulf, the previously 

record depth was 1100 m. Sibogagorgia sp. was observed repeatedly, another depth record for the 

genus. On the SW corner of the mound was a very high density seep community with tube worms 

in the cracks in the rocks and a large bed of mussels (Bathymodiolus brooksi and B. heckerae) on 

the cliff face and accumulating at the base of a small platform (Figure 2-59). Associated with the 

tube worms and mussels were the common species Munidopsis sp., Alvinocaris muricola, 

Ophioctenella acies, as well as a few additional species awaiting more complete taxonomic 

identifications. 

Figure 2-59. High density seep community.

The area between the mound and the escarpment was covered with plain sediments with occasional 

holothurians and a few rattail fish. At the base of the escarpment (Figure 2-60) were accumulations 

of sediments with carbonate crusts and white staining, possibly from outwatering of the 

escarpment. Above the foot of the wall were near-vertical outcrops and occasional platforms. 

Though one outcrop did not appear to be sedimentary (lacked any bedding), it did appear to have 

fossils on the exposed side. Also, there were 2 – 3 cm wide, 20 cm long “tubes” that, in vertical 

cross-section formed fans and on the rock surface, the tops were rounded and packed together.

This lower portion of the scarp harbored small aggregations of tube worms in vertical cracks and 

pockets in the rock. Corals were not observed or abundant until the top of the scarp, where 

paramuricids became remarkably dominant and abundant, each hosting a single Asteroschema

ophiuroid (Figure 2-61). Bamboo corals, including Keratoisis and Leipidisis were present, mostly 

on the east facing outcrops and walls.
66

Figure 2-60. The base of the escarpment.

Figure 2-61. Paramuricid hosting a single Asteroschema ophiuroid.
67

At the top of the escarpment a smooth, terraced, “limestone-like” seafloor dominated for at least 

75-100 m distance where only holothurians and shrimp were observed. The greatest abundance 

of Paramuricea sp octocorals were at the rim of this “limestone” cap. About 5 m below these 

octocorals was a ~5 m-tall wall with the densest concentration of bamboo corals, including 

Keratoisis and Leipidisis, observed during this project (Figure 2-62). This wall also included a 

narellid primnoid which may be a new species. Further south along the ridge the carbonate 

outcrops were largely devoid of colonial cnidarians, although occasional colonies of the octocoral 

Iridogorgia. sp. were encountered along with a large Bathypathes- like black coral.

Asteroschema sp. brittlestars, shrimp, and isopods were observed on Paramuricea sp. and 

Chrysogorgia sp. corals. Overall, 7 octocoral species were observed. Only two fish were observed 

during the transit to the top and then down the southeast side of the escarpment- a synaphobranchid 

eel and a Coryphaenoides rat tail. The corals Clavularia rudis, Sibogagorgia cauliflora, 

Paramuricea biscaya B1, Paramuricea biscaya B2, Chrysogorgia averta, Iridogorgia 

magnispiralis, Iridogorgia magnispiralis, Keratoisidihnae I2, Keratoisidinae N1a, Keratoisidinae 

nr J2a, and Lepidisis sp. D1c were collected from the DC583 site (ch). 

Figure 2-62. Bamboo coral colonies.

2.3.1.24 DC673 (2,250 to 2,600 m depth)

The DC673 site was identified on BOEM 3D-seismic data using bathymetric contours with 

seafloor amplitude underlay. Like DC583, the site is located near the northwestern end of the 
68

Florida Escarpment at 28.31°N, 87.144°W where the water depth at the base is about 2,600 m. this 

site was dived upon one time, during the 2010 Ron Brown cruise. 

At the base of the Escarpment massive carbonates were often colonized by corals (Bathypathes) 

with seepage around their base hosting chemosynthetic tube worms and mussels. About 100 m up 

the escarpment there is an impressive feature of live mussels surrounded by a thicket of living tube 

worms in a crack in the wall (Figure 2-63). Tubeworms at this site were covered with what 

appeared to be zoanthids. A diversity of corals are present on the wall of the escarpement and up 

to the top of the escarpment along a ridge including bamboo corals, Paramuricea sp. with 

ophiuroids, Chrysogorgia with associated shrimp, Acanthogorgia, Sibogagorgia and Corallium

and at least two black coral species (perhaps Bathypathes and Stauropathes). Three species of 

bamboo corals were especially abundant along the wall at ca. 2380-2400 m depth, including a 

Lepidisis whip coral and 2 possible Keratoisis spp. The octocoral community here is in general 

similar to that observed at DC583 in 2009. 

Figure 2-63. An octopus takes refuge in a dense tube worm bush and mussel bed (DC673).

On the top of the escarpment the substrate was mostly sediment with occasional low relief 

outcrop/boulder with white sediment accumulation around the base. We reached a second ridge at 

ca. 0330 local time. Another ridge at ~2250 m depth hosted similar coral species in addition to two 

species of Iridogorgia and an additional paragorgid not encountered previously (Figure 2-64). We 

left the bottom at 0640 local time anticipating an on time recovery on the surface. The corals 

Clavularia rudis 1c, Anthomastus sp., Corallium niobe, Sibogagorgia cauliflora, Paramuricea 

biscaya B1, Paramuricea biscaya B2, Chrysogorgia averta, Iridogorgia magnispiralis, 

Iridogorgia splendens, Keratoisidinae I2, Keratoisidinae N1a, Keratoisidinae nr J2a, and Lepidisis

sp. D1c were collected from the DC673 site (Appendix A-2).
69

Figure 2-64. A single Iridogorgia sp. is seen settled on a rocky outcrop surrounded by a few 

small colonies of Paramuricea biscaya (DC673).

2.3.2 Other Coral Sites Discovered Since the DWH Incident (Sorted by Depth)

The last ROV cruise to natural coral sites of this project occurred in late 2010, about 4 months 

after the DWH leak was capped. By the time of that cruise we had examined 3D seismic surveys 

with BOEM scientists and had chosen several potential hard-ground sites with good potential to 

host coral communities in the vicinity of the Macondo Well. On the last dive of the 2010 Ron 

Brown cruise we dove on one of these sites in an unexplored portion of lease blocks MC338 and 

MC294 and discovered the coral community in lease block MC294 described above. During a 

NSF funded cruise in December of 2010 we visited another coral community in MC388 that had 

been discovered using a drift camera during a cruise designed by C. Fisher, H. Roberts, and W. 

Shedd (using criteria developed from this project), funded by the NRDA effort and led by W. 

Shedd of BOEM. Subsequent to that, an exploration cruise using the AUV Sentry and a towed 

camera system discovered several other coral sites that were subsequently dived on using an ROV. 

The sites selected for exploration for this effort were also chosen by H. Roberts, W. Shedd, and C. 

Fisher, and the high success rate of the cruise was a direct reflection of lessons learned during this 

project and innovative use of the AUV Sentry for site exploration. The majority of corals at each 

of these sites has been individually documented and imaged for ongoing monitoring efforts. In 

addition to these sites, another site discovered as part of the NRDA effort in AT 357 was explored 

by the PIs of this proposal and a subset of the many corals at this site identified and imaged for 

monitoring. Below is a short description of each of those sites.
70

2.3.2.1 MC159/203 (950 m depth)

The MC159/203 site was discovered first by the AUV Sentry and then characterized using an ROV 

in October of 2011. The site is about 17 nm W-NW of Macondo at 28.8°N, 88.64°W in 950 m 

water depth. This is another site with heavy colonization of mostly large (old) coral colonies in a 

small area. A total of twenty coral colonies were found at this site: Two Acanthogorgia aspera, 

Seven Swiftia cf. koreni (Figure 2-65), and eleven Paramuricea sp. B3. Several of the corals at 

this site were also tangled in longline, and limited damage to the colonies from the longline was 

noted. Also notable at this site were the relatively high numbers of shark egg cases attached to the 

corals. The corals Acanthogorgia aspera, Paramuricea sp. B3, and Swiftia cf. koreni were 

collected from the MC159/203 site (Appendix A-2).

Figure 2-65. Swiftia cf. koreni with longline at MC159/203

2.3.2.2 MC036 (1110 – 1120 m depth) 

Three-D seismic maps of the MC036 site revealed extensive areas of potential hardground and 

numerous conduits for seepage over a large area along a SSW to NNE tending ridge. This site

was explored by drift camera and although numerous signs of seepage and a few carbonates were 

observed, no corals were identified. A northern portion was further surveyed by the AUV Sentry

and numerous carbonates were identified with a few corals associated with one group of boulders. 
71

The first area of corals was surveyed during an ROV cruise in October 2011 and then additional 

potential targets identified from the Sentry survey that were explored by ROV in March 2012 

discovered an additional two groups of corals within two hundred m of the first group on the same 

(SE) edge of the ridge.

The site is about 17 nm N-NE of Macondo at 28.935°N, 88.204°W in about 1,115 m water depth. 

A total of at least 26 colonies were identified at this site (the exact number cannot be distinguished 

from the video and photographic records of the dives but several images of “colonies” appear to 

include 3 or more colonies), in three areas spread over about 200 m of the ridge edge. It is likely 

that further exploration would find additional corals at this site. At least 20 colonies of 

Paramuricea sp (dominated by species B3, Figure 2-66) and 6 colonies of Chrysogorgia sp. 

(Figure 2-67) were imaged for evaluation and long term monitoring. Two remains of what 

appeared to be dead Paramuricea were present and their condition (lack of small branches) 

suggests these had been dead for many years.

Figure 2-66. Paramuricea B3 with attached ophiuroid near marker M18 at MC036.
72

Figure 2-67. Chrysogorgia sp at MC036.

2.3.2.3 MC506 (1,040 m depth)

The MC506 site was discovered first by the AUV Sentry and then characterized using an ROV in 

October of 2011. The site is about 35 nm SW of Macondo at 28.45861°N, 88.85091°W in 1,040 

m water depth. This is a relatively small site with all known coral colonies on 2 large carbonate 

boulders located in close proximity to each other. A total of ten coral colonies were found at this 

site: 9 Paramuricea sp B3 and one Chrysogorgia sp. All colonies were large and there was no 

sign of recent recruitment of colonial corals to this site. One of the Paramuricea was partially 

tangled in what appears to be longline (Figure 2-68). Two other colonies had large areas that 

appeared to have been dead for a long time, with small growing portions on the tip end of a few 

branches. The corals Paramuricea sp. B3 and Chrysogorgia sp. 1b were collected from the MC506

site (Appendix A-2).
73

Figure 2-68. Paramuricea sp B3 from MC506. Note long line in lower right and colony in 

forefront.

2.3.2.4 AT357 (1,050 m depth) 

The AT357 site is an area of high reflectivity in the 3D seismic that was originally identified by 

BOEM (then MMS) scientists from a 1997 survey. It is an area of relatively low vertical relief, 

and therefore did not make the final cut of exploratory sites originally planned for the Lophelia II 

project. This site was originally discovered during a soft-sediment sampling cruise led by Dr. Jim 

Payne as part of the NRDA effort following the Deepwater Horizon incident, and has since been 

surveyed on three cruise led by PIs of this program. It is centered near 27.59°N, 89.70°W in about 

1,050 m water depth. It has recently been mapped in high resolution using AUVs as part of the 

GoMRI EcoGig program. This is one of the largest coral communities in the deep GoM, and is 

several times larger than any currently known in the >1,000 m depth range. The main part of the 

site is approximately 300 m wide (east-to-west) and 200 m north-to-south and contains numerous 

outcropping carbonate slabs, platforms, and crusts. There is a large Madrepora oculata reef 

structure in the northern, central part of the site, surrounded by octocoral communities, primarily 

Paramuricea type B3 also including a variety of other gorgonian and black coral species as well 

as small Madrepora (Figure 2-69) colonies. At least 62 coral colonies have been identified and 

imaged for long term monitoring at this site. It also hosts one of the most diverse arrays of coralassociated fauna seen at any site (e.g., ophiuroids, galatheid crabs, shrimp, and polychaetes). Along 

the northern edge of the site is a fairly extensive area of seepage with outcropping carbonates, a 
74

mussel bed and occasional methane bubble streams. There are also additional, unexplored areas of 

potential coral abundance and/or active seepage in the area, which remain ripe for future 

investigations. The corals Anthothela sp. 3, Paramuricea sp. B3, and Chrysogorgia sp. 1a were 

collected from the AT357 site (Appendix A-2).

Figure 2-69. Paramuricea sp with attached ophiuroid brittle stars at AT 357.

Figure 2-70. The edge of the large Madrepora reef with a Paramuricea type B3 colony. 

Associates include an orange basket star, galatheid crabs, and ophiuroids.
75

2.3.2.5 MC297 (1,580 m depth)

The MC297 site has the most extensive coral development below 1,000 m within 20 nm around 

Macando. It is located at 28.68°N, 88.34°W at 1,580 m depth. This site was initially targeted for 

photo survey by the Sentry AUV based on side scan maps provided by BP. The site is composed 

of two areas separated by about 370 m, each with numerous colonies, and a few scattered boulders 

and occasional isolated corals in between the two areas with higher density coral development. 

The site was first visited by an ROV in October of 2011 and at that time hydroid development on 

many of the corals both areas was very similar to the level of hydroid development on corals at the 

MC338/294 site discovered during the Ron Brown 2010 cruise. It has been visited three times by 

ROV between October 2011 and October 2012. Most of the corals discovered at this site have 

been identified (using nearby physical markers) and imaged for continued monitoring. There are 

at least 80 Paramuricea sp (Figure 2-71), three Bathypathes sp., two bamboo corals (One Isididae 

and one Keratoisidinae I2), two other unidentified octocorals (Figure 2-72) and two areas with 

encrusting Clavularis rudis. In addition, two other octocorals overgrown with zoanthids and four 

apparent Paramuricea skeletons that still retained very small branches (and so likely died recently) 

were present in these two areas. The corals Clavularia rudis, Paramuricea biscaya B1, 

Paramuricea biscaya B1a, Paramuricea biscaya B2, and Keratoisidinae I2 were collect from the 

MC297 site (Appendix A-2).

Figure 2-71. Paramuricea biscaya at MC297.
76

Figure 2-72. Unidentified octocoral at MC297.

2.3.2.6 MC388 (1,840 – 1,960 m depth)

The presence of coral at the MC388 site was discovered during a drift camera cruise in late 2010. 

The site was further explored by the AUV Sentry and the manned submersible Alvin in December, 

2010 during an NSF funded project. Approximately 34 corals at this site were discovered and 

imaged for monitoring during a NRDA sponsored ROV cruise in October 2011. An additional 

five corals were discovered and imaged during a cruise with the NOAA OER ship Okeanos 

Explorer in March of 2012. Finally, an additional 27 corals were discovered and imaged during a 

cruise supported by the Gulf of Mexico Research Initiative (GoMRI) EcoGig project and the 

Schmidt Ocean Institute. As a result of all of these efforts, numerous carbonate outcrops colonized 

with coral colonies and tube worms spread over an area of several square km have been 

documented and imaged for monitoring. The site is about 14.4 nm SE of Macando at 28.63°N, 

88.17°W and ranges in depth from about 1,840 to 1,960 m. In addition to whip corals 

(Stichopathes sp.) and encrusting Clavularis rudis octocorals, a total of at least 44 Paramuricea 

biscaya, 4 bamboo corals (in the family Keratoisididae), 6 black corals (Bathypathes sp.), and an 

unidentified octocoral are present at this site (Figure 2-73 and Figure 2-74). The corals Clavularia 

rudis, Paramuricea biscaya B1, Paramuricea biscaya B1a, Paramuricea biscaya B2, and 

Keratoisidinae I2 were collected from the MC388 site (Appendix A-2).
77

Figure 2-73. Whip coral (Stichopathes sp.), Paramuricea biscaya, black coral 

(Bathypathes sp.), and encrusting Clavularis rudis octocoral in MC388.

Figure 2-74. Unidentified white octocoral in front of Paramuricea biscaya at MC388.
78

3 OCEANOGRAPHIC AND GEOLOGIC SETTING

This chapter addresses the carbonate chemistry at multiple sites in the Gulf, the implications of 

currents at two sites on coral larval dispersal, tests of particulate and sediment dispersal at two 

sites to estimate biogeochemical fluxes, and testing of biweekly sediment trap samples for the 

presence of coral larva.

3.1 THE CARBONATE SYSTEM AND PH

Portions of this chapter have been published in Limnology & Oceanography and should be cited 

as: Lunden, J.J., S.E. Georgian, and E.E. Cordes. (2013). Aragonite saturation states at cold-water 

coral reefs structured by Lophelia pertusa in the northern Gulf of Mexico. Limnol. Oceanogr.

58:354-362.

3.1.1 Introduction to Carbonate Testing Performed

In this chapter, we describe the carbonate system from the water column and deep waters of the 

GoM in an effort to augment the existing global data set of oceanographic carbonate chemistry, 

particularly in marginal seas such as the GoM. Additionally, we sought to better understand the 

distribution of the aragonite saturation state (Ωarag) in the context of cold-water coral presence in 

the GoM. Related to this objective, we tested two hypotheses regarding Ωarag and L. pertusa

distribution ― that areas of L. pertusa presence have higher Ωarag values than areas lacking L. 

pertusa, and that L. pertusa skeletal density positively correlates with Ωarag. With the establishment 

of baseline values of Ωarag in deep waters, especially near sensitive biological communities such 

as cold-water coral reefs, we will be able to detect future changes in carbonate chemistry resulting 

from ongoing acidification. 

3.1.2 Methods of Carbonate Sampling and Analysis

3.1.2.1 Sample Collection 

All water samples (n = 143) were collected during the Lophelia II 2010 expedition using a CTD 

rosette (water column) and the ROV Jason II (bottom water) onboard the NOAA Ship Ronald H. 

Brown (15 October – 5 November 5 2010). Fourteen deep-water stations (depth > 300 m) in the 

GoM were sampled (Figure 3-1). Lophelia pertusa was present at eight of these sites: GC354, 

GB535, MC751, MC796, VK826, VK862, and VK906). Water column samples (n = 79) were 

collected using a CTD rosette (SBE-32 submersible array firing assembly, 2.5 L bottle-1). Bottom 

water samples (n = 64) were collected using a custom-made hydraulically-powered 7-Niskin bottle 

(1.7 L bottle-1) array fitted to the ROV. Upon recovery of the ROV and CTD rosette, water samples 

were collected from the Niskin bottles and stored in 500 mL polyethylene containers in a cool, 

dark location until analysis (<2 hours after reaching the surface). 
79

Figure 3-1. Seven Niskin bottle array fitted to ROV Jason during the 2010 Lophelia II 

cruise.

3.1.2.2 Analytical Methods 

pH (total hydrogen scale) of each sample was measured in duplicate at ~22°C using an Orion 5 

Star pH meter with Ross electrode calibrated with Tris-HCl buffer (Dickson Lab, Batch 4, Scripps 

Institution of Oceanography). Precision for pH analyses was 0.002 units (standard deviation (s.d.)). 

pH values were corrected for pressure and temperature effects using CO2SYS (Oak Ridge 

Laboratory, Oak Ridge, TN, Pierrot et al. 2006). Total alkalinity of each sample was measured in 

duplicate at 22°C according to SOP3b (Dickson et al. 2007) using a Mettler-Toledo DL15 

autotitrator with 0.1 N HCl in 0.6 M NaCl solution and calibrated against certified reference 

materials (Dickson Lab, Batch 105, Scripps Institution of Oceanography). Precision for total 

alkalinity analyses was 4.6 μmol kg-1 (s.d.). Temperature (°C), salinity in practical salinity units

(PSU), and pressure in decibars (dbar) were obtained in situ using a SBE19 CTD (for bottom water 

samples on ROV Jason) and a SBE 9/11+ CTD (for water column samples). Total alkalinity was 

normalized to salinity of 35 parts per thousand (ppt) according to Millero et al. (1998). The 

aragonite saturation state (Ωarag and the calcite saturation state (Ωcal), dissolved inorganic carbon 

(DIC), and carbonate ion ([CO3

2-

]) concentrations were calculated at in situ pressure using 

CO2SYS. The dissociation constants for carbonic acid (K1 and K2) are from Dickson and Millero 

(1987) and the aragonite solubility product constant (Ksp) is from Mucci (1983). 
80

3.1.2.3 Statistical Analyses 

All statistical analyses were conducted using JMP 8 (SAS). Normality was tested using the 

Shapiro-Wilk W test, with p > 0.05 indicating normally distributed data. When assumptions of 

normality were not met, non-parametric statistics (Mann-Whitney U test and Kruskal-Wallis 

analysis of variance (ANOVA)) were employed. 

3.1.3 Results and Discussion of Carbonate Study

3.1.3.1 Total Alkalinity and pH in Surface Waters

Total alkalinity (TA) in surface waters ranged from 2349-2411 μmol kg-1 (mean: 2388). Surface 

pHT ranged from 8.08-8.16 (mean 8.11). Total alkalinity measurements from the surface layer 

agree well with prior work in the GoM. Our TA measurements fall within the range reported by 

Keul et al. (2010, 2333.0-2411.9 μmol kg-1) in the same region, but do not fit the TA-salinity 

relationship established by Lee et al. (2006). However, this relationship was nearly significant (r

2

= 0.225, p = 0.0632) and it is likely that the limited number of surface samples in our study (n = 

16) impedes this relationship. Salinity-normalized TA in our study (mean: 2375 μmol kg-1) was 

higher than average salinity-normalized TA (nTA) in sub-tropical Atlantic seawater (2291 μmol

kg-1, Millero et al. 1998). However, neither alkalinity relationships calculated from Lee et al. 

(2006) nor Millero et al. (1998) included data from the GoM.

An additional source of the TA-salinity disparity could be the role of the Mississippi-Atchafalaya 

system. Riverine input from this system exports high amounts of bicarbonate as a result of rock 

weathering along the river’s track (Suchet et al. 2003). This flux facilitates a delivery of high TAlow salinity water to the northern GoM, potentially distorting the TA-salinity relationship 

generally observed in oceanic waters. Recently, Guo et al. (2012) described the carbonate 

chemistry dynamics of the Mississippi River plume in the GoM. They observed elevations in TA 

due to input from the Mississippi River of up to 400 μmol kg-1compared to ambient surface 

seawater (TA = 2330 – 2700 μmol kg-1at S = 0). While our study area was outside of the 

Mississippi-Atchafalaya river system, the GoM’s carbon cycle is strongly influenced by inputs 

from this plume (Guo et al. 2012). 

Recently published results from a 2007 survey of the GoM carbonate system agree well with the 

surface values from our dataset (Wang et al. 2013). The buffering capacity of seawater may be 

inferred by the ratio of TA to DIC (TA:DIC). At high TA:DIC, the effects of CO2 influx may be 

offset by the buffering actions of alkaline species such as bicarbonate and carbonate. The TA:DIC 

ratio of the surface waters in the GoM is relatively high compared to other coastal systems, 

including the Gulf of Maine (Wang et al. 2013). According to the Global Ocean Data Analysis 

Project (GLODAP), open-ocean surface pH typically ranges from 7.95-8.35 (mean: 8.11, Sabine 

et al. 2005). However, this wide-scale analysis did not include samples from the GoM. Mean 

surface pH in our study is identical to the global average (8.11) and very close to the North Atlantic 

Ocean average (8.12) and is consistent with a 0.1 unit decline in pH from pre-Industrial estimates 

of surface ocean pH (Raven et al. 2005). While this value is expected to further decline over the 

next century as anthropogenic ocean acidification continues, disparate effects may be observed 

across different water bodies with different TA:DIC parameters. Establishment of the baseline 
81

carbonate chemistry parameters in the GoM from this study, as well as those of Wang et al. (2013), 

will permit observation of future changes in pH and associated carbonate variables.

3.1.3.2 Total alkalinity and pH in the Deep GoM

In deep waters (> 300 m depth), TA ranged from 2264-2382 μmol kg-1 (mean: 2316) (Figure 3-2, 

Figure 3-5). TA was significantly different among sites (Kruskal-Wallis test, H = 32.3, p < 0.001). 

Salinity-normalized TA (nTA) also significantly differed among sites (Table 3-1, Kruskal-Wallis 

test, H = 36.4, p < 0.001). nTA was lowest at 100-200 m depth and began to increase at 200 m 

depth (Figure 3-1). At depth, pH ranged from 7.84-8.03 (Figure 3-2) and varied significantly 

among sites (Table 3-1, one-way ANOVA, F10,49 = 4.65, p < 0.001). Highest mean pH was 

observed at the two deepest sites, DC673 (2500 m) and GC852 (1400 m). Dissolved inorganic 

carbon (DIC) at depth ranged from 2135-2231 μmol kg-1 (mean: 2185) and [CO3

2-

] ranged from 

92-123 μmol kg-1 (Figure 3-4).

In addition to the processes described above, the increase in anthropogenic CO2 is likely to 

contribute to pH declines throughout the water column. Elevated CO2 in the atmosphere leads to 

direct changes in surface water chemistry, and these changes may be translated to depth relatively 

quickly if the rate of vertical exchange via vertical mixing and eddy diffusion approaches the rate 

of lateral exchange by deep-water currents. The Loop Current of the GoM frequently sheds large 

cyclonic eddies that are propagated westward (Sturges et al. 2010). These eddies, coupled with 

wind-induced shallow-water currents, combine to produce downwelling along the northern GoM 

shelf break increasing the rate of vertical exchange (Chang and Oey 2010). There is a relatively 

low level of lateral exchange of deep water among the GoM, the Caribbean, and the Atlantic Ocean 

resulting from the relatively shallow sill depths of the two openings to the GoM: the Yucatan Strait 

at approximately 2000 m and the Florida Strait at approximately 700 m. In a relatively closed 

oceanographic system subjected to strong anthropogenic forcing such as the GoM, these processes 

could potentially contribute to our observed decreases in pH and aragonite saturation state with 

depth. 

Several factors are known to influence the inorganic carbon system in deep waters. One of the 

primary controls on total alkalinity is the precipitation and dissolution of CaCO3. In the surface 

ocean, precipitation of CaCO3 by planktonic calcifiers removes bicarbonate, a predominant 

substrate for calcification (Hofmann et al. 2010). As these organisms die, the shells and tests 

descend to the seafloor, resulting in a net accumulation of alkaline species with increasing depth 

(Milliman et al. 1999). This process may increase normalized total alkalinity, which was observed 

initially at 200 m in the GoM (Figure 3-2); however, other processes such as nitrification, 

denitrification, and the decomposition of organic matter cannot be excluded (Stumm and Morgan 

1981). The decomposition of organic matter throughout the water column also influences 

carbonate chemistry dynamics at depth through the release of CO2 resulting in a decline in pH with 

depth. In the GoM, lowest pH values were observed within the depth range of the oxygen 

minimum zone (300-800 m, Guo et al. 1995), reflecting the interaction between organic matter 

decomposition and pH (Figure 3-3, Figure 3-5).

Progressive ocean acidification will alter the carbonate parameters of the water column of the 

global ocean. Recently published data show that pH decreased by 0.026-0.043 units from 1991-
82

2010 in intermediate waters (500-1,100 m) of the Rockall Trough (McGrath et al. 2012). This 

change was induced by an estimated influx of anthropogenic CO2 of roughly 15 μmol kg-1over 

two decades. Like the GoM, the Rockall Trough provides habitat for several species of cold-water 

corals, including the scleractinians L. pertusa and Madrepora oculata (White and Dorschel 2010). 

If similar changes in pH occur in the GoM, Ωarag would be expected to decrease as much as 0.1 in 

deep waters. Sustained ocean acidification at this rate could potentially result in undersaturation 

of aragonite in the deep GoM by the end of this century.

Figure 3-2. Water column profile of normalized total alkalinity (nTA) (μmol kg1) from 0 to 1600 m.

Figure 3-3. Water column profile of pH (total hydrogen scale) from 0 to 1600 m.
83

Table 3-1.

Carbonate Chemistry Parameters of Deep-water Sites in the Northern GoM

* Denotes presence of Lophelia pertusa.

3.1.3.3 Aragonite Saturation State

Surface Ωarag ranged from 4.02-4.36 (mean: 4.18). At depths greater than 300 m, Ωarag for all 

stations ranged from 0.98-1.69 (Table 3-1, Figure 3-4, Figure 3-5), with the values under 1.0 

measured at 2596 m depth. Ωarag for L. pertusa sites ranged from 1.28-1.69. Ωarag varied 

significantly among sites where L. pertusa was present (one-way ANOVA, F5,31 = 7.3798, p < 

0.001), with highest values found in the eastern-most sites, including the VK bioherms (Figure 

3-5). 

Within the depth range of L. pertusa in the GoM (300-600 m), total alkalinity was lower at sites 

where L. pertusa was present (Kruskal-Wallis test, H = 5.0905, p = 0.0241); however, this 

relationship does not hold when total alkalinity is normalized to salinity (Kruskal-Wallis test, H = 

2.7638, p = 0.0964), as salinity is slightly lower at sites where L. pertusa is present (presence mean 

salinity: 35.05, absence mean salinity: 35.38, Kruskal-Wallis test, H = 17.5330, p < 0.001). 

Furthermore, there was no significant difference in pHT where L. pertusa was present and absent 

(Kruskal-Wallis test, H = 0.2893, p = 0.5907) (Figure 3-5). 

Since Ωarag covaries with depth, an exponential decay function was used to model changes in Ωarag 

with depth, 

Ωarag = ae

bx(depth) + c (2)

where a = 3.13122, b = -0.00573, and c = 1.15589 (Figure 3-4). Analysis of the residuals between 

the function and empirically-derived values shows no significant difference in depth-corrected 

Ωarag between sites of L. pertusa presence and absence (Kruskal-Wallis test, H = 0.529, p = 0.467).

Site

ID

Lease 

block

Depth 

(m)

Latitude 

(°N)

Longitude 

(°W)

nTA 

(μmol kg-1) pHT

[CO3

2-

] 

(μmol kg-1) Ωarag

1 DC673 2387-

2597 28.31 87.31 2312.25-2324.55 7.94-7.98 105.60-108.79 0.98-1.13

2* VK826 455-526 29.15 88.01 2288.69-2334.74 7.89-8.03 95.64-123.31 1.33-1.69

3* VK906 390-441 29.07 88.38 2253.82-2332.04 7.85-7.95 92.49-113.85 1.31-1.61

4* VK862 307 29.11 88.38 2304.13 7.92 115.5 1.66

5* MC885 620 28.06 89.72 2321.37-2343.03 7.87-7.93 87.97-98.35 1.19-1.33

6* MC796 530 28.14 89.76 2315.29 7.91 100.6 1.38

7* MC751 437 28.19 89.79 2304.5 7.93 105.5 1.48

8 GC249 787-832 27.74 90.52 2326.07-2331.12 7.92-7.95 96.22-102.33 1.26-1.33

9 GC246 868 27.71 90.65 2315.71-2322.83 7.91-7.94 93.2-99.7 1.20-1.29

10 GC852 1485 27.11 91.17 2333.86-2341.5 7.97 105.6-106.4 1.20-1.21

11 GC140 283-320 27.81 91.54 2303-2312.49 7.89-7.92 107.86-115.61 1.55-1.67

12* GC354 551 27.59 91.82 2297.6-2310.93 7.86-7.88 89.35-93.17 1.22-1.28

13 GB299 338 27.69 92.23 2285.48-2297.69 7.91-7.92 108.15-113.26 1.54-1.62

14* GB535 510-534 27.43 93.58 2297.8-2387.45 7.87-7.92 94.17-102.25 1.31-1.41
84

The aragonite saturation state is increasingly recognized as one of the most important drivers of 

framework-forming cold-water coral presence (Davies and Guinotte 2011). A key concern for the 

persistence of cold-water coral reefs and their associated communities is the shoaling of the 

aragonite saturation horizon as a result of ocean acidification. According to the results presented 

here for the GoM, the cold-water coral reefs formed by Lophelia pertusa presently lie above the 

aragonite saturation horizon (ASH); however, shoaling of the ASH is expected to continue as a 

result of ongoing anthropogenic ocean acidification (Guinotte et al. 2006). While it is not known 

how natural populations of L. pertusa will cope with aragonite-undersaturated conditions, 

experimental evidence suggests a potential for acclimation to CO2-induced acidification. Over the 

course of six months, L. pertusa from the North Atlantic was able to grow under laboratory 

conditions at Ωarag of 0.93 (Form and Riebesell 2012). However, this study was limited in its 

number of genetic replicates (n = 2), so it remains unclear if a population of genetically-distinct 

individuals will respond similarly. Populations from the Porcupine Seabight and Darwin Mounds 

have been shown to be highly clonal (Waller and Tyler 2005), and these and the rest of the North 

Atlantic populations are genetically isolated from the GoM (Morrison et al. 2011). Although our 

findings suggest that L. pertusa in the GoM are tolerant of the current saturation states described 

here, its response to acidification may be different from individuals of the North Atlantic 

populations. Future work should explore the effects of ocean acidification on L. pertusa to 

determine if acclimation to decreasing pH is possible in populations beyond the North Atlantic.

When comparing sites only within the depth range of L. pertusa, Ωarag was lower at sites where L. 

pertusa was present than at sites where it was absent, conflicting with our hypothesis that high 

Ωarag would coincide with L. pertusa presence. This result is likely due to the depth constraints on 

Ωarag discussed above. L. pertusa was absent at sites just below 300 m (GB299 and GC140, 320-

340 m depth). This suggests that Ωarag is unlikely to exclusively control L. pertusa presence, and 

that other environmental factors not accounted for in the present study may significantly contribute 

to L. pertusa’s distribution and abundance in the GoM. Factors other than ocean chemistry shown 

to limit cold-water coral distribution include temperature, availability of hard substrata for larval 

settlement, and current speeds adequate to provide sufficient food resources (Roberts et al. 2009). 
85

Figure 3-4. Water column profile of the aragonite saturation state (Ωarag) from 0 

to 1600 m. Solid line represents the function Ωarag = aebx(depth) + c. 

Dashed line represents Ωarag = 1.0.
86

Figure 3-5. Distributions of (A) normalized total alkalinity (nTA) (μmol kg-1), (B) pH (total 

hydrogen scale), (C) carbonate ion concentration ([CO32-]) (μmol kg-1), and (D) the 

aragonite saturation state (Ωarag). Areas in white represent no data.
87

3.2 CURRENTS ASSOCIATED WITH VK826 AND GC852 AND IMPLICATIONS FOR 

LARVAL DISPERSAL

3.2.1 Introduction to Current Tests Performed

The dispersal of Lophelia pertusa larvae, like the dispersal of the tiny larvae of many marine 

invertebrates, is subject to the prevailing currents, as tiny larvae are not strong swimmers, but are 

transported like passive drifters (Morrison, Chap.4). Knowledge of the local circulation is 

necessary to determine the potential for self-seeding of a reef versus exporting larvae to or 

recruiting larvae from distant reefs. For this study current meter moorings were deployed for 13 

months at two well-developed deep water coral sites that represent different depth ranges and flow 

regimes. The Vioska Knoll site (VK826) is in 455 m total water depth and the Green Canyon site 

(GC852) is in 1,424 m total water depth. At VK826 an Aanderaa RCM7 current meter was located 

5 m from the bottom and an upward-looking acoustic Doppler current profiler (ADCP) was 

positioned 9 m above the bottom with an current profiling range of nearly 100 m. Farther west in 

1424 m water depth, the mooring at GC852 was equipped with Aanderaa RCM7 current meters at 

5 m and 100 m above the bottom. Both moorings were designed to collect data in the near-bottom 

boundary layer, as well as the prevailing currents in the water column above. For simplicity the 

VK826 instruments will be referred to as CM03 (lower) and ADCP (upper), while the GC852 

instruments will be referred to as CM00 (lower) and CM01 (upper).

The effect of the bottom boundary layer at each site was observed, as well as the linkage between 

the flow over the mounds and the fluctuations of the Loop Current (LC) and associated eddies. 

The mooring data exhibit strong motions in the inertial-tidal range, which impact the local 

circulation and sedimentary environment. L. pertusa are filter feeders and typically occur in areas 

with substantial currents. The observed short-term velocity fluctuations were generally along slope 

and considerably larger than the mean flow at both locations.

The mooring data was also used to assess the numerical model of deep Gulf circulation which was 

seeded with inert particles to provide a much broader view of potential larval transport routes, as 

well as areas of the slope that experience accelerated currents and are therefore favorable to deep 

coral communities.

3.2.2 Deep Mooring Observations at Two Lophelia pertusa Sites

3.2.2.1 Overview

Current meter moorings were deployed at the sites of two deep water coral communities in the 

northern GOM for about13 months. The GC852 mooring was deployed in 1,420 m total water 

depth in the Green Canyon block to the west of the Mississippi Canyon and the VK826 mooring 

was located on the western flank of the DeSoto Canyon in 455 m total water depth (Figure 3-6). 

The moorings were designed to measure currents in both the frictional bottom boundary layer and 

in the background flow in the water column above. There was 100% data return for both current

meters at GC852 and the ADCP at VK826 (
88

Table 3-2). The minimum threshold for recording current magnitude for the Aanderaas is 1.1 cm/s, 

below which the vector components of the current aren’t resolved. Due to the very weak currents 

at GC852, slack currents below the 1.1 cm/s threshold accounted for 25.9% of the total record for 

CM00 and 34.1% of the total record for CM01. These slack currents appear to be real and not the 

result of fouling. The good data return on current meter CM03 at VK826, which was 5 m off the 

bottom, was about 83%, which was most likely due to temporary fouling of the instrument. There 

was strong coherence between CM03 and the lowest bin of the ADCP, indicating that there was 

likely some fouling of CM03 during the deployment (see Figure 3-7). The correlation coefficients 

for the current magnitude, u-, and v-components for CM03 and ADCP bin1 are 88%, 97% and 

72% respectively.

Figure 3-6. Bottom bathymetric contours (meters) in the GoM. The 

mooring sites are indicated with red crosses. The location of the 

Macondo 252 well is indicated with a blue circle.

Figure 3-7. Current speed during the first 21 days of the deployment at 450 m (red) and ADCP 

bin 1 (blue) at 444 m.
89

Table 3-2.

LSU Deep Coral Study Moorings at Green Canyon 852

Mooring 

location; 

Total depth

Dates of 

Deployment

Days Instrument Type 

(S/N) 

Instrument 

Depth

Percent 

Data 

Return

GC852

27°06.783”N

91°09.874”W

1,420 m

Begin: 

8/30/09 02:30

End: 

10/22/10 16:56

418 Aanderaa 

sn#12701 (CM01)

1320 m 100%

Aanderaa 

sn#12700 (CM00)

1415 m 100%

VK826

29°09.690”N

88°01.063”W

455 m

Begin:

9/4/09 14:00

End: 

10/15/10 18:29

406 ADCP 300 

sn#1219 (ADCP)

446 m 100%

Aanderaa 

sn#12703 (CM03)

450 m 83%

3.2.2.2 Green Canyon 852

3.2.2.2.1 Historical Observations

Green Canyon 852 (GC852) is the study site for a natural hardground coral community in 

approximately 1,400 m water depth. This area has been the focus of several BOEM observational 

and modeling studies. The first long term mooring, FF4, was deployed to the east of GC852 at 

26°44.4’N; 91°59.7’W in 1,750 m water depth from April 1987 to September 1988. Hamilton 

(1990) reported that the currents at 1,650 m below the surface at FF4 were weaker (≤ 5cm s1) than 

measured at similar depths at other locations along the slope, but the 20-25 day fluctuations were 

also observed at 1,650 m directly south of FF in 3000 m water depth. These fluctuations are 

attributed to the westward and upslope propagation of Topographic Rossby Waves (TRWs) 

(Hamilton, 1990).

Two deep-water moorings were deployed in the Green Canyon area from 1999-2004. Mooring J1 

(co-supported by British Petroleum and BOEM) was deployed 102 km to the east of GC852 in the 

GC782 block (~90°15’W, 27°15’N) at the top of the escarpment in 1,372 m total water depth

(Hamilton et al., 2000). J1 was deployed from September 1999 to September 2000 and was 

equipped with current meters at 10 m, 100 m, and 400 m above the bottom. A very strong event at 

the beginning of the deployment resulted in a maximum speed at J1 of about 50 cm s-1, but this 

was considerably less than the maximum of 95 cm s-1observed at 1,600 m at a mooring to the east 

along the escarpment in nearly 2,000 m total water depth. Mean velocities were calculated from 

40-hour low-pass (HLP)-filtered current records for the 100- to120-day intervals that corresponded 

with large amplitude fluctuations at each mooring. The mean currents at J1 were consistently 

westward, except for the upper two current meters during the second interval. The mean amplitudes 

were below 5 cm s-1for all records, except the bottom-most current meter during the first interval. 

The largest means were observed nearest the bottom. The generally weak currents measured at J1 

indicated that deep TRWs were blocked from propagating either westward or into shallower water 

above the escarpment at this location.
90

A BOEM-supported observational study of currents near the Sigsbee Escarpment combined data 

from four deep-water deployments with satellite remote sensing data to look at the relationship 

between surface eddies and deep currents (McKone et al., 2007). The locations of the first two

deployments were south of the GC852 site in approximately 2,200 m total water depth. The first 

deployment from 2/16/00 – 7/29/00 was located at 26o05.17’N; 29o38.4’ and the second 

deployment was from 7/30/00-5/05/-1 and was located at 26o05.5’N; 29o39.4 N. Maximum current 

speeds exceeded 140 cm s-1in the surface above 100 m, but were less than 30 cm s-1at the bottom 

two current meters. The lowest mean speeds were recorded in the transition layer at 1,200 m. The 

mean direction at the bottom was westward and rotated clockwise with increasing height from the 

bottommost current meter at 2,213 m to the next current meter at 1,973 m. Spectral analysis of the 

data supported the presence of TRWs, although it was concluded that the source of the TRWs in 

the deep layer was non-local and not forced from the surface layer by motions related to the LC 

and associated eddies. 

3.2.2.2.2 Mooring Data Analyses

The low frequency current variability was analyzed by removing the tidal and inertial oscillations 

with a 40-HLP filter. Basic statistics of currents for both raw hourly-sampled data and 40-HLP 

data are presented in Table 3-3. The daily current vectors are plotted for the 40-HLP data over the 

entire record in Figure 3-8. The upper panel shows the first 200 days of the deployment for both 

instruments, followed by the second 200 days of the deployment in the lower panel. The coherence 

between the upper and lower currents increases during the strong flow events at the beginning of 

the deployment and from days 280-340 during the latter half of the deployment. 

Table 3-3.

Basic Statistics for Green Canyon 252 Mooring Deployment

Depth(m)/

instrument

Mean

Raw

U V 

Speed

Maximum

Raw

U V Speed

Standard

Deviation

Raw

U V Speed

Standard

Deviation

40-HLP

U V Speed

Ratio

KE40: 

KEraw 

(%)

Prin.

Axis 

Dir 

(True)

1325/

CM01

-.89 .-06 3.75 13.99 11.18 22.60 4.12 2.55 3.19 3.91 2.38 3.01 89.62 -12.53

1415/

CM00

-.63 .61 5.04 14.39 11.56 22.60 5.79 2.51 3.91 5.51 2.28 3.56 89.27 -14.24
91

Figure 3-8. Daily averaged 40-hour low-pass filtered current vectors for CM01 and CM00.

The temperature records at GC852 for top and bottom current meters are highly coherent through 

most of the deployment, although the extremes are more pronounced in the water column (CM01) 

than at the bottom (CM00). The large amplitude temperature changes correlate with the strong 

current events at the beginning of the deployment and mid-way through the second half of the 

deplyment (Figure 3-9).

Figure 3-9. 40- hour low-pass filtered temperature records at CM01 (top) and CM00 

(bottom).
92

Figure 3-10 and Figure 3-11 show that the cooler water coincides with a reversal in flow from 

south to north at both near the bottom and in the water column above. There is also considerable 

clockwise rotation of the current with height above the bottom as an eddy feature moves over the 

mooring during the first 37 days. During the latter half of the deployment there was a slight 

increase in the flow over the mound between days 280 and 340 (Figure 3-12). During this series 

of events the flow in the water column above the mound was only weakly coupled with the flow 

at the bottom, when compared to the first 60 days. From closer inspection of the entire record, 

there appears to be some blocking of the flow to the south in the near bottom, possibly because of 

the placement of the current meter on the mound.

Figure 3-10. Current vectors (top), corresponding current direction (blue), and 

temperature (green) (bottom) for CM01 days 1-60.

Figure 3-11. Current vectors (top), corresponding current direction (blue), and 

temperature (green) (bottom) for CM00 days 1-60.
93

Figure 3-12. Current vectors measured at CM01 (top) and CM00 (bottom) on days 280-340.

The standard deviation ellipse for both depths at GC852 (

Figure 3-13 left) and the corresponding progressive vector diagrams (Figure 3-13 right)

demonstrate a counterclockwise rotation of the mean current direction with height above the 

bottom. The larger mean for the current meter near the bottom, the magnitude and the direction of 

the flow for this study are consistent with the historic data in the Green Canyon. 

Figure 3-13. Standard deviation ellipses (left) and progressive vector diagrams (right) for CM01 

(red) and CM00 (black).
94

The large velocities observed at the beginning of the record are due to upper level cyclones that 

move over the mooring during the following intervals: September 20-40 (days 20-40 in Figure 3-8, 

Figure 3-10, andFigure 3-11) and October 20-November 8 (days 50-70). Both of these events were 

accompanied by the cooler temperatures at the mooring, and correspond to the pronnouced loops 

in the progressive vector diagram at the beginning of the record. The southern edge of an 

anticyclone passed over the mooring in February and resulted in relatively warm water and 

northwesterly flow. On July 1, 2010, which corresponds to day 300 in Figure 3-9 andFigure 3-12, 

an anticyclonic (warm core) eddy passed over the mooring resulting in a rise in temperature (Figure 

3-9) and a shift from southerly flow to northwesterly.

The largest peaks in the velocity spectrum for both current meters (Figure 3-14) are at 23 and 27-

28 days, with smaller peaks at ~20, ~17, ~14, and ~12 days. The peak at 23 days was prominent 

in the spectra by McKone et al. (2007) at the current meter just off the bottom. McKone et al. 

(2007) also observed energy peaks at 13 and 16 days. There is significantly more energy in the ucomponent at both levels, although there is relative more energy in the v-component in the water 

column. As noted in the discussion above, there is very little flow toward the south and limited 

north-south fluctuations overall in the bottom layer. 

The largest peaks in the rotary spectra (Figure 3-15) are at 12.5 and ~24 hours with smaller peaks 

between 24 and 27, which correspond to tidal and inertial motions. There is nearly 5-fold increase 

in the peak clockwise frequency in the bottom layer. The dominant signal in the rotary specta is 

clockwise for near bottom and up in the water column, which is expected.

Figure 3-14. Spectra of CM00 (top) and CM01 (bottom) u-velocity (blue) and vvelocity (green) smoothed with a 5 Hanning window.
95

Figure 3-15. Rotary Spectra at CM01 (left) and CM00 (right).

3.2.2.3 Vioska Knoll 826

3.2.2.3.1 Historical Observations

The VK826 current meter mooring was deployed on the western flank of the DeSoto Canyon at 

455 m depth at 29o09.69’N, 88o01.063’W. The L. pertusa community is situated on exposed 

carbonate knolls and ridges above a low-relief mound of soft sediments. The mounds are 

approximately 90 m high and 1-2 km in diameter. The individual L. pertusa thickets are 1-15 m 

high and up to 500 m long. The surficial geology, bathymetry, and coral community distribution 

in the vicinity of the VK826 mooring were previously described by Schroeder (2002). The center 

of the low-relief mound observed by Schroeder (2002) had a minimum water depth of 434 m and 

was centered at 29o09.5’N, 88o01’W, just 370 m to the southeast of the mooring location. The 

mooring design for this study was intended to provide an understanding of near bottom boundary 

layer flow over the mounds, which is directly impacted by the topography and the large-scale flow 

in the water column above the mounds.

The DeSoto Canyon has been the focus of many in situ physical oceanography studies over the 

past 35 years, although the availability of satellite imagery has greatly improved our understanding 

of the complex circulation with a broad range of horizontal scales of motion. The background flow 

in the canyon is driven by a combination of the large-scale geostrophic flow, LC eddies and rings, 

wind-driven currents, upwelling/downwelling, tides, and internal oscillations. The boundary layer 

flow is influenced by the rough topography associated with the ridges and hummocks, as well as 

the reflection of internal waves by the sloping bottom topography.

The DeSoto Canyon Eddy Intrusion Study (2000; hereafter referred to as DC2000), funded by 

BOEM (formerly MMS), was a comprehensive physical oceanographic program designed to 

understand how the LC and associated eddies exchange momentum and mass between the deep 

gulf and the shelf within the DeSoto Canyon (Hamilton et al, 2000). The program featured in-situ 

current measurements, hydrographic data and satellite images to observe and document LC 

intrusions into the DeSoto Canyon to examine the exchanges of momentum, mass, and vertical 

vorticity associated the LC-slope interactions over a two-year field season (DC2000). Of specific 
96

relevance to this study were the current and hydrographic measurements at mooring B2, located 

at 29o12.72’N, 87o52.279’W, which was14.38 km northeast of the VK286 mooring along the 500-

m isobath. The DC2000 mooring featured current meters at 200, 300 and 490 m; temperature 

recorders at 62, 150, and 250 m; and an ADCP at 90 m. The data were subdivided and analyzed 

according to intervals of sustained flow in the upper 200 m. During the summer of 1997 the 

northern edge of a deep water cyclone forced anticyclonic flow into the canyon resulting in 

eastward flow above 200 m with weaker westward currents below. The along-isobath variance 

was considerably larger at 500 m than the cross-slope variance and the principal direction was 

along slope toward the southwest with a mean current speed of ~5 cm/s (DC2000). The second 

interval was characterized by rapid succession of cyclonic LC frontal eddies at a time when the 

LC was well extended into the northeastern GoM. The circulation in the canyon was cyclonic at 

all depths except above 100 m in the head of the canyon. The 500-m standard deviation ellipse at 

B2 exhibited an even larger ratio of along slope to cross-slope variance with a mean velocity of 

nearly 10 cm/s directed toward the southwest. The third interval was characterized by anticyclonic 

flow over the central part of the canyon that extended over the water column. The flow on the 

western flank again exhibited strong topographic rectification with the principal direction toward 

the southwest and average speed less than 5 cm/s.

3.2.2.3.2 Mooring Data Analyses

Basic statistics of currents for both raw hourly-sampled data and 40-HLP are presented in Table 

3-4 for both the ADCP data (depths 372-444 m) and the current meter at 450.3 m. There is a 

counter clockwise rotation of the mean flow with height above the lowest ADCP bin. The means 

are considerable smaller than the fluctuations due to the back and forth nature of the current which 

is aligned with the topography. The daily subsampled 40 HLP velocity vectors in ADCP bins 1, 

11, 21, and 31 are shown in Figure 3-16 for the entire deployment. The switching back and forth 

of the current is apparent in the contours of the u-component and occurs through the water column 

(Figure 3-17). Although the v-component exhibits small fluctuations in time, it varies with height 

above the bottom. The clockwise rotation of the flow with height above the site is also apparent in 

the standard deviation ellipses (Figure 3-18) and in the progressive vector diagrams for selected 

depth records (Figure 3-19). We can also see from the progressive vector diagrams that there was 

considerably more variation in the direction of the flow during the beginning of the deployment.

The spectra of velocity components for the near-bottom and topmost ADCP bins at VK826 (Figure 

3-20) are quite different than the spectra computed for GC852 (Figure 3-14) and the upper and 

lower spectra are more dissimilar than the upper and lower spectra at VK826. The largest peaks in 

the spectra for both levels are near 50 days, but it should be noted that the scale for the y-axis is 

double for the upper bin. The lower bin has relatively large peaks in the 25-33 day and 16-25 day 

range, but they are actually of the same magnitude as the upper bin. As discussed previously, there 

is very little energy in the v-component compared to the u-component. 

The rotary spectra are compared for the upper most ADCP bin and the current meter just above 

the bottom (Figure 3-21). The clockwise component is dominant at both levels, as it was at GC852 

(Figure 3-15), which is to be expected. The peaks are more concentrated around the tidal-inertial 

frequencies higher up in the water column than near the bottom. There is not only very little energy 

at 12.5 hours in the upper record, but the peak at ~12.5 hours is the largest in the near bottom. This 
97

is also quite different from the rotary spectra at GC852, where the energy is more narrowly 

concentrated in the lower level and the 12.5 hour peak is relatively small. 

Empirical orthogonal functions (EOFs) computed from the ADCP velocity components are 

presented in Figure 3-22. More than 90% of the variability is captured in mode 1 for both 

components. The greater variation of the v-component than the u-component with depth is 

apparent in each of the modes, as it is in the contour plots of these components (Figure 3-17). The 

clockwise rotation from southeasterly to more easterly occurs between 400 m and 410 m, which 

is apparent in the progressive vector diagrams.

The temperature record from the current meter at 450.3 m for the entire deployment is presented 

in Figure 3-23 along with the u-component of velocity at 372 m. The temperature and east-west 

flow are negatively correlated, whereas the u- and v-components are positively correlated. These 

correlations indicate that southwesterly currents transport relatively warm water from the DeSoto 

Canyon to the site and when the currents switch direction, northeasterly currents transport 

relatively cooler water from offshore to the site.
98

Table 3-4.

Basic Statistics for Vioska Knoll 826 Mooring Deployment

Depth

(m)

/SN

Mean

Raw

U V Speed

Maximum

Raw

U V Speed

Standard

Deviation

Raw

U V Speed

Standard

Deviation

40-HLP

U V Speed

Ratio

KE40: 

KEraw 

(%)

Prin.

Axis 

Dir 

(True)

372 -6.0 -3.9 15.3 42.5 30.1 56.2 15.7 7.1 10.6 15.1 5.5 10.4 88.6 17.9

374 -6.0 -3.8 15.2 39.4 23.5 54.8 15.6 7.0 10.6 15.0 5.4 10.4 88.7 17.8

376 -5.9 -3.8 15.1 39.8 25.3 52.9 15.6 6.9 10.6 15.0 5.3 10.4 88.8 17.8

378 -5.8 -3.7 14.9 40.5 24.4 53.3 15.5 6.9 10.6 14.9 5.3 10.4 88.9 17.9

380 -5.8 -3.7 14.8 38.6 24.4 54.3 15.4 6.8 10.6 14.8 5.2 10.4 89.1 18.1

382 -5.8 -3.6 14.6 41.0 23.5 58.5 15.3 6.7 10.6 14.8 5.2 10.4 89.3 18.0

384 -5.8 -3.5 14.5 41.7 21.1 61.6 15.3 6.7 10.6 14.7 5.1 10.4 89.4 18.1

386 -5.8 -3.4 14.3 39.4 21.3 59.0 15.1 6.6 10.6 14.6 5.1 10.4 89.5 18.0

388 -5.7 -3.3 14.2 40.6 24.7 59.3 15.1 6.4 10.5 14.5 5.0 10.3 89.7 17.7

390 -5.7 -3.2 14.1 41.9 24.7 58.1 15.0 6.3 10.4 14.5 4.8 10.2 89.8 17.3

392 -5.7 -3.0 14.0 43.4 24.5 56.9 14.9 6.1 10.4 14.4 4.7 10.2 90.0 16.9

394 -5.7 -2.9 13.9 46.5 25.7 56.4 14.9 5.9 10.3 14.4 4.5 10.1 90.2 16.3

396 -5.7 -2.7 13.7 46.1 27.7 53.6 14.8 5.7 10.2 14.4 4.2 10.0 90.4 15.5

398 -5.7 -2.6 13.6 46.1 26.3 51.2 14.8 5.5 10.1 14.3 4.0 9.9 90.6 14.6

400 -5.7 -2.4 13.5 46.2 25.4 53.3 14.8 5.3 10.0 14.3 3.8 9.9 90.9 13.8

402 -5.7 -2.2 13.5 43.5 26.2 53.9 14.7 5.0 10.0 14.3 3.6 9.8 91.2 12.8

404 -5.8 -1.9 13.4 42.9 30.9 54.0 14.7 4.8 9.9 14.3 3.4 9.8 91.6 11.8

406 -5.8 -1.7 13.3 41.5 26.4 57.1 14.7 4.6 9.8 14.3 3.2 9.7 92.0 10.7

408 -5.8 -1.5 13.2 41.0 24.5 56.8 14.6 4.3 9.7 14.2 3.0 9.6 92.4 9.7

410 -5.8 -1.3 13.1 42.5 26.6 55.8 14.6 4.2 9.7 14.2 2.9 9.6 92.6 8.8

412 -5.8 -1.2 13.1 41.5 21.8 54.9 14.5 4.0 9.6 14.2 2.8 9.5 92.9 8.1

414 -5.8 -1.1 13.0 39.5 15.1 57.3 14.4 4.0 9.5 14.0 2.7 9.4 93.0 7.5

416 -5.8 -1.0 12.9 39.2 17.4 54.1 14.3 3.9 9.3 13.9 2.7 9.3 93.0 7.1

418 -5.7 -0.9 12.8 40.9 18.2 52.8 14.1 3.9 9.2 13.8 2.6 9.1 93.1 6.6

420 -5.6 -0.9 12.7 42.1 16.4 52.4 14.0 3.8 9.1 13.7 2.6 9.0 93.1 6.3

422 -5.5 -0.9 12.5 40.1 17.7 51.0 13.8 3.8 8.9 13.5 2.5 8.9 93.0 6.1

424 -5.3 -0.9 12.3 40.4 16.6 50.9 13.6 3.7 8.7 13.3 2.5 8.7 92.8 6.1

426 -5.0 -0.9 12.2 43.6 16.2 48.2 13.4 3.7 8.5 13.1 2.5 8.5 92.7 6.0

428 -4.8 -1.0 12.0 44.8 17.2 45.9 13.2 3.7 8.3 12.9 2.5 8.3 92.5 6.1

430 -4.7 -1.0 12.0 43.1 15.7 44.8 13.2 3.7 8.2 12.9 2.5 8.2 92.4 6.0

432 -4.6 -1.0 12.1 41.9 16 44.6 13.3 3.7 8.2 13.0 2.5 8.2 92.4 5.4

434 -4.9 -1.0 12.5 40.4 15.6 48.5 13.7 3.8 8.4 13.4 2.5 8.4 92.5 5.2

436 -5.1 -1.0 12.9 41.3 15.7 48.7 14.1 3.9 8.6 13.8 2.6 8.6 92.6 5.1

438 -5.0 -1.0 13.1 42.4 16.1 49.9 14.3 3.9 8.7 14.0 2.6 8.7 92.5 4.9

440 -4.9 -1.0 13.1 40.7 17.3 47.2 14.3 4.0 8.6 14.0 2.6 8.7 92.3 4.8

442 -4.8 -1.0 13.0 40.3 16.9 47.1 14.2 4.0 8.5 13.9 2.6 8.5 92.0 5.0

444 -4.6 -0.9 12.8 40.2 17.3 45.6 13.8 4.0 8.1 13.4 2.5 8.2 91.3 3.9

450.3/

Sn12703

-2.6 -0.3 9.9 44.4 13.5 44.4 11.8 3.4 7.6 11.4 2.5 7.1 91.3 5.3
99

Figure 3-16. Stick plots for ADCP bins 1 (444 m), 11 (424 m), 21 (404 m), and 31 (384 m).

Figure 3-17. Contours of U- and V-components of velocity (cm/s ) for ADCP bins 1-

37.
100

Figure 3-18. Standard deviation ellipses for CM03 (446 m), ADCP 

bin 1(444 m), and ADCP bin 37 (372 m).

Figure 3-19. Progressive vector diagram for ADCP at 5 depth levels.
101

Figure 3-20. Spectra of u-velocity (blue) and v-velocity (green) for bins 1 

(446 m) and 37 (372 m) smoothed with a 5 Hanning window.

Figure 3-21. Rotary Spectra for the uppermost ADCP bin 37 at 372 m (left) and for the current 

meter at 450.3 m (right).
102

Figure 3-22. EOFs for ADCP bins 1-37 velocity components 

at VK826. Modes 1-3 are indicated by red, blue, 

and green lines, respectively.

Figure 3-23. 40-HLP temperature from CM03 at 450 m and 40-HLP ucomponent of velocity from ADCP bin 37 (372m).
103

3.2.3 Summary of Deep Water Currents Analysis 

Moorings were deployed at two well-developed L. pertusa communites in the northern GoM. The 

shallower site, VK826, is located to the east of the Mississippi Delta at a depth of 455 m on the 

western flank of the DeSoto Canyon and the second site, GC852, is located to southwest of the 

Mississippi Delta at a depth of 1420 m on the northern Gulf slope. The current strength was 

markedly different between the two sites, although the current direction was along the slope at 

both locations, which was to be expected. The mean current flow at both locations was also 

considerably smaller than the magnitude of the fluctuations. The maximum velocity at GC852 

peaked at only 22.6 cm/s, whereas the maximum current measured at VK826 was 60 cm/s. The 

spectra at VK826 was characterized by broad peaks at 80 days and 50 days in both the near bottom 

and in the water column above. The frequency response centered at 18 days and 30 days in the 

near bottom at VK826 was not as strong in the water column above. The rotary spectra at VK826 

produced a broad frequency response, which was unlike the response at GC852. Both the spectra 

and the rotary spectra at GC852 indicated very strong inertial-tidal motions, as well as strong 

frequency response at 12.5 hours. Broad peaks in the frequency response were observed at GC852 

centered at 80 days and 50 days, but with reduced magnitude compared to the inertial-tidal 

response.

The progressive vector diagrams were computed to give an estimate as to how far a drifter could 

be transported by the currents at a given site over a period of time. The much stronger currents at 

VK826 resulted in a net vector displacement over the length of the deployment on the order of 

2500 km. The net vector displacement at GC852 was on the order of 350 km over the length of the 

deployment. The mooring data suggest that there is greater potential for transport of coral larvae 

away from the site at VK826, which is important for establishing new colonies. The currents at 

both sites exhibited counterclockwise rotation with height above the bottom. The current direction 

at VK826 was most certainly becoming better aligned with the orientation of the slope upon which 

the mound is situated.

3.3 TIME SERIES ANALYSIS OF PARTICULATE ORGANIC INPUT

3.3.1 Objective of Mass Flux Testing

The goal of this sub-project was to investigate settling mass, organic carbon and associated 

biogeochemical fluxes sinking from the upper water column to deep-water coral sites. To achieve 

this we deployed and recovered two long-term (~10 month) time-series sediment trap/current 

meter moorings; one each at two different sites of interest in the GoM. 

3.3.2 Deployment of Sediment Traps

The instruments used were PARFLUX Mk 78H-21 time series sediment traps (Figure 3-24) each 

of which was deployed on a 60 m tall mooring (Figure 3-25). One trap was deployed at VK826

(water depth 463 m) and the other at MC751 (water depth 436 m). Each mooring was designed 

so that the upper surface of the sediment trap was located 6 m above the seafloor and, for each 

mooring, a current meter was placed 2 m above the surface of the trap to measure current velocities 

(speed, direction) and water temperature. 
104

Figure 3-24. PARFLUX sediment traps during deployment.

Figure 3-25. Schematic of 21-cup time-series sediment trap moorings used for this project

Following release to the seafloor, each trap mooring was re-located using the Jason ROV and repositioned precisely, immediately adjacent to the deep-water coral site under investigation (Figure 

3-26, Figure 3-27).
105

Figure 3-26. Sediment Trap Mooring 1 (Site MC751) deployed at 28°11.64’N, 089° 47.90’W on 

09/01/09.

Figure 3-27. Sediment Trap Mooring 2 (Site VK826) deployed at 29° 09.63’N, 088° 01.13’W 

on 09/04/09.

Each trap was programmed such that the sampling stage would rotate to collect material into a 

fresh sample cup every 21 days with the first sampling cup being rotated into position to start 

collecting material on 9/11/2009 and the final sample’s collection period ending on 7/2/2010. Each

250-ml sample cup was filled with DMSO preservative prior to deployment so that, in addition to 

our planned biogeochemical analyses, splits of the same samples could also be analyzed for 

microbial, and larval studies (including molecular biological investigations).

3.3.3 Recovery of Sediment Traps

The Ron Brown cruise in fall 2010 saw the recovery of both time-series traps. Upon recovery, it 

was clear that, while the trap from site VK826 had continued collecting samples successfully 

throughout the sampling period, the invasion of a jellyfish into the sediment trap funnel at the 

MC751 site had blocked any samples from being collected after 20 Nov 2009. Accordingly, all 

21 anticipated samples from VK826 together with just 5 samples from MC751 (collected 

contemporaneously with the first 5 samples from VK826) were available for analysis. In the case 

of the VK826 site, the samples are of potentially wider significance because the sampling period 

both preceded and overlapped with the timing of the Deepwater Horizon (DWH) oil spill, which 

resulted in surface oil slicks that passed directly over the VK826 site. In separate work, funded by 

NSF Rapid (2010) and NRDA (2011) we have continued a near-continuous two-year time series 

from fall 2009 to summer 2011 to investigate whether there is any evidence for seafloor impact 

related to surface-slicks caused by the DWH accident. Those later results are not included in this 

report but archived sample-splits from this project remain stored under NRDA-approved chain of 

custody protocols. 
106

3.3.4 Results of Mass Flux Tests

All samples have now been analyzed for mass flux, together with concentrations of organic and 

inorganic C, H, N, Al, Ba, Ca, Fe, Mg, Mn, Si, Sr & Ti. Complete mass and biogeochemical flux 

data sets are presented in Appendix B-1 and the accompanying current meter records are presented 

in Appendix B-2. From the biogeochemical data, relative proportions of biogenic opal, biogenic 

carbonate, detrital and organic matter fluxes can be calculated. 

The mass flux for both traps is directly comparable (Figure 3-28) and the complete record for 

VK826 shows a pronounced peak in winter 2009-10. Further, analysis of the contents of the trap 

samples reveals that they are dominated by lithogenic inputs (Figure 3-28) and the same is true for 

MC751 (data not shown). 

Combining these data with an analysis of the current meter data from the VK826 mooring (Figure 

3-29) which shows maximum current speeds in winter 2009-10 and slower velocities in springsummer 2010, we surmise that the bulk of the flux to the VK826 trap in the northern GoM was 

related to winter storm activity. Importantly, however, there are also significant variations in the 

relative abundance of both biogenic carbonate and organic matter throughout the record (Figure 

3-5; right), particularly in spring 2010 which coincides with the timing of the DWH Oil Spill.

Figure 3-28. Time-series data, 2009-10. Left: Mass Flux data (both sites); Right: Four 

component analysis (VK826).
107

Figure 3-29. Current meter data displayed as a stick diagram showing direction (stick 

orientation) and speed (stick length) from the VK826 site. (Data for MC751 not 

shown). Note that maximum velocities occur in winter 2009-10 and much calmer 

conditions prevailed in spring-summer 2010.

Considering these data in closer detail, the following trends become apparent. First, the 

concentration of particulate organic carbon (POC) in the VK826 trap (at a site underlying surface 

oil slicks within the first week following the April 20, 2010 explosion and fire on the DWH rig) 

increased to its highest levels in the weeks following the spill (Figure 3-30). The initial increase 

in this POC trend, however, pre-dates the DWH accident and may be attributable to spring bloom 

activity commencing as early as late March/early April of 2010. Within the period of highest POC 

concentrations (Figure 3-7a) the concentrations of Ba are also much higher than at any other time 

in the record. This, again, could be entirely consistent with a primary productivity signal linked 

to spring bloom activity. These time-series data were first reported as part of a presentation at the 

Association for the Sciences of Limnology and Oceanography (ASLO) aquatic sciences meeting 

in Puerto Rico in February 2011 and at the Information Transfer Meeting (ITM) meeting held in 

New Orleans in March 2011. Resulting from that, our group was subsequently funded by NSFRapid and NRDA grants to continue our studies into the Spring and Summer of 2011 to investigate 

these trends further. While similar fluxes and POC trends recur in the 2011 spring period, 12 

months beyond theDWH spill, the one trend reported here that was not observed again, 

subsequently, was the increase in carbon/nitrogen (C:N) ratios observed for sediment trap samples 

at the VK826 site as the discharge from the DWH site progressed (Figure 3-7c). This is intriguing 

because high C:N ratios in the natural environment are often interpreted as evidence for more 

maturated organic matter. On a like-for-like basis, the high C:N ratios observed for samples 

collected during the DWH discharge period were not observed at any other time at the same site, 
108

including during the following year’s spring bloom, throughout a two-year period, 2009-2011. A 

working hypothesis, therefore, is that these samples may reflect input of relatively “old” organic 

carbon that may be related to the DWH accident. While representative (50%) splits of these 

samples have been transferred to Tim Shank’s laboratory for larval analyses, 10% of all these 

samples have been retained by us under NRDA-approved chain-of-custody protocols for future 

potential analyses, including hydrocarbon fingerprinting and C-isotope analyses. 

Figure 3-30. Time-series data, 2009-10 for (a) POC concentrations; (b) Ba concentrations; (c) 

C:N molar ratios at VK826.

3.4 LARVAL FLUX TO CORAL SITES - SEDIMENT TRAP RESULTS

Time-series sediment traps (Figure 3-31a) were deployed at two sites at ~500 m water depth in the 

Viosca Knoll 826 and Mississippi Canyon 751 lease blocks to collect the temporal flux of settling 

particles, including larvae of deep-sea fauna. These traps were operationally defined to 

autonomously collect biweekly samples in 21 sample bottles (Figure 3-31b) from September 2009 

through September 2011.

Sediment traps with ID’s GOMEX 01 VK01 M2 and RR1 VK02 M2 were deployed at Viosca 

Knoll 826 site from September 2009 to July 2010 and from June 2010 to January 2011, 

respectively. 
109

a b

Figure 3-31a,b. Diagrammatic views of (a) a McLane Parflux sediment 

trap and (b) the rosette of 500 ml collection bottles and 

autonomously rotated by a motor at the base of the funnel

As standard for deep-sea sediment trap larval collections, the biweekly trap samples were 

preserved in-situ in the sample bottles in 10% dimethylsulfoxide (DMSO). Upon retrieval on deck, 

sediment traps and sample bottles were extensively photographed. Sample bottles were 

individually documented via digital imagery, labeled, capped and sealed with tape, and placed in 

secure refrigerated storage at 4oC. Upon reaching port, the samples were shipped in refrigerated 

storage at the Woods Hole Oceanographic Institution. Maintained in a 4°C cold room, the samples 

were run through 5 mm and 1 mm sieves, and divided into splits for biogeochemical, hydrocarbon, 

and larval recruitment analyses. 

All samples were stored in capped and sealed 500 mL plastic vials. The <1mm sediment size 

fraction was wet-split into 10 parts (relative standard deviation (RSD) of 5%) and the 1mm-5 mm 

size fraction was wet-split into two parts (RSD of 10%). The >5 mm samples were stored without 

splitting. 
110

The trap deployed at Mississippi Canyon 751 from September 2009 to July 2010 (trap ID: 

GOMEX 01 MC01 M1) physically did not function after only a few collection sample bottles had 

rotated (presumably less than 2 months of sampling). As such, parallel temporal analyses of the 

composition and distribution of organismal material between VK826 and MC751 as originally 

planned was not possible. We focused our efforts instead on assessing the larval composition and 

long-term variability in the collections made at VK826 from September 2009 to July 2010 and 

from June 2010 to January 2011.

3.4.1 Biogeochemical Analyses from VK826

The total mass flux shows several peaks throughout our time series (Figure 3-32) that appear to 

correlate with winter storm deposition from the Mississippi River and is composed primarily of 

lithogenic material originating from the Mississippi outflow. During the oil release period, total 

mass flux was low but showed an increase in flux as the sample time period elapsed. Fluctuations 

in particulate inorganic carbon roughly correspond to total mass flux and was also low but 

increased during the oil release period (Figure 3-33). Similarly, particulate organic carbon was 

low, but increased during the oil release period (Figure 3-34). In contrast, C/N increased during 

the spill period (Figure 3-35). A similar increase was not observed during the following spring. 

Figure 3-32. Total mass flux (mg/m2/day) from sediment trap series at Viosca Knoll. Shaded 

area indicates timing and duration of oil spill.

2
111

Figure 3-33. Particulate inorganic carbon (PIC), (mg/m2/day) from sediment trap series at 

Viosca Knoll. Shaded area indicates timing and duration of oil spill.

Figure 3-34. Particulate organic carbon (POC), (mg/m2/day) from sediment trap series at Viosca 

Knoll. Shaded area indicates timing and duration of oil spill.

0.00

5.00

10.00

15.00

20.00

25.00

30.00

35.00

40.00

45.00

0.00

10.00

20.00

30.00

40.00

50.00

60.00

70.00

80.00
112

Figure 3-35. C/N, as calculated using organic carbon from sediment trap series at Viosca Knoll. 

Shaded area indicates timing and duration of oil spill.

3.4.2 Larval Composition and Abundance from VK826

Enumeration of organisms in the different size fractions (>5 mm, 1-5 mm, <1 mm) was conducted 

using a Leica MZApo microscope. The >5 mm and 1-5 mm sample size fractions were sorted 

directly in DMSO. Samples from the <1 mm size fraction were additionally washed with water 

through 300 μm and 63 μm sieves. Organisms from all samples were removed as they were counted 

and archived in shell vials with DMSO and stored in a refrigerator at 4° C. Pteropod shells and 

copepods were the most abundant organisms identified in the >5 mm and 1-5 mm fractions (Figure 

3-36). The number of shells from both organisms displayed large peaks during the oil spill period. 

Gastropod and bivalve shells were most abundant in the <1 mm size fraction in samples collected 

between August and October 2010. The number of gastropod shells increased through September 

and peaked in mid-October, while bivalve shells showed a small peak in early September and 

another small peak in early October (Figure 3-37). No coral or echinoderm larvae were observed 

during this period. 

0.00

2.00

4.00

6.00

8.00

10.00

12.00

14.00

25-Sep

25-Oct

25-Nov

25-Dec

25-Jan

25-Feb

25-Mar

25-Apr

25-May

25-Jun

25-Jul

25-Aug

25-Sep

25-Oct

25-Nov

25-Dec

25-Jan

25-Feb

25-Mar

25-Apr

25-May

25-Jun

25-Jul

25-Aug
113

Figure 3-36. Number of individual specimens collected over time. The most abundant 

organisms in the 1-5 mm fraction were pteropod shells (red) and copepods (green). 

Shaded area indicates timing and duration of oil spill.

Figure 3-37. Number of individual specimens collected over time. The most abundant 

organisms in the <1 mm fraction are gastropod shells (violet) and bivalve shells (blue). 

Numbers were pooled from the 300 μm-1mm and 63-300 μm fractions.

0

20

40

60

80

100

120

0

50

100

150

200

250
114

The preponderance of shells from various species (e.g., larval bivalves and gastropods) were void 

of tissue and soft-bodied organisms were rare or absent in these collections. Two possible 

explanations are that 1) the deployment duration and preservation method resulted in the 

decomposition of tissue prior to our analyses, and/or that 2) due to the collection time and location, 

the vast majority of material collected was already dead or decomposing at the time of sampling. 

If the first explanation is considered most likely, this observation would be counter to all previous 

trap deployment and larval collections (more than 8), conducted between 2000 m to 2600 m depth 

for 6 to 10 month deployment intervals. This explanation would provide insight into our inability 

to extract DNA from sediment trap larvae despite the fact that many of the copepods did contain 

tissue (this could also suggest an issue with preservation). We conducted over a dozen attempts 

to extract genomic DNA, utilizing both off-the-shelf Qiagen Extraction Kits for small amounts of 

tissue (highly successful in the past for obtaining larval DNA from identical sediment traps) and 

our 10% DMSO recipe. If the second explanation holds true and the sediment trap material was 

collected at a time and location in which the vast majority was already dead and decomposing, 

then rationales for this observation would include unknown dynamics associated with 

nutrient/productivity blooms in this region and potentially some influence of the DWH oil spill. 

Without additional information, including some MC252 fingerprint analysis on the collected 

materials, discerning between these two potential options is difficult.

The DWH blowout released hydrocarbons at ~1,500 m depth from April 20, 2010 through July 15 

2010. While some of those hydrocarbons persisted in a deep plume, about 15% formed a slick at 

the surface (Camilli et al 2010). Within a week of the blowout, our Viosca Knoll trap site was 

underneath this surface slick (Figure 3-38). The Mississippi Canyon 751 trap site was located 

outside of the area covered by the surface slick. The collection of mostly shelled larval forms 

without tissue coincident with the Viosca Knoll 826 trap’s location under the surface slick suggests 

a linkage between these two observations.
115

Figure 3-38. The extent of surface slicks on May 2, 2010. Red stars indicate position of 

sediment traps.

In parallel with the C/N ratio and prior to the largest increase in concentration of particulate organic 

carbon in the VK826 trap (underlying surface oil slicks within the first week following the DWH 

explosion on April 20, 2010), the abundance of pteropods and copepods increased to their highest 

levels in the weeks during the spill. Larval gastropods and bivalve abundance was maximal in the 

fall in the samples analyzed to date. As noted previously, the high C/N ratios observed for samples 

collected during the DWH discharge period were not observed at any other time at this site, 

including during the following year’s spring bloom, throughout the two-year sampling period, 

2009-2011. Given that high C/N ratios are considered to derive from more mature organic matter, 

a working hypothesis is that the observed fluctuations in either organism composition or 

abundance may correspond directly to the input of relatively “old” organic carbon that may be 

related to the DWH accident. 

These time-series data were first reported as part of a presentation at the ASLO Aquatic Sciences 

meeting in New Orleans in February 2013, as Govindarajan, A. F., S. Manganini, C. R. German, 

T. M. Shank (2013) Effects of the Deepwater Horizon Oil Spill on Biogenic Fluxes and Larval 

Recruitment.
116

4 COMMUNITY STRUCTURE, BIODIVERSITY, AND BIOGEOGRAPHY

Deep-water corals provide important sources of habitat heterogeneity on continental shelves 

worldwide. They create habitat for a diverse group of associated fauna that may occur only in 

association with the corals or in abundances orders of magnitude above that on the surrounding 

seafloor (Jensen and Frederiksen 1992, Henry and Roberts 2007, Mosher and Watling, 2009). In 

the Northeast Atlantic alone, over 1,300 species have been recorded living in and on L. pertusa

habitats in physical and photographic samples (Rogers 1999, Roberts et al. 2006, Henry and 

Roberts 2007). On two reef structures alone in Norway, 256 species were recorded from recovered 

coral blocks (Jensen and Frederiksen 1992). In the Porcupine Seabight in the Northeast Atlantic, 

313 taxa were collected in 7 box core samples from coral mounds (Henry and Roberts 2007). The 

diversity of the community on these reefs rivals the diversity of many tropical zooxanthellate coral 

reefs (Rogers 1999). 

However, these studies all involved dredge and box core samples that include species that are 

likely not intimately associated with coral structure but inhabit the sediments beneath the coral 

framework and in the case of dredges perhaps as much as 100s of meters away. In the GoM, 68 

taxa of large macrofauna and megafauna (> 1 mm sieve size) were found in closely associated 

with L. pertusa in quantitative community collections obtained with custom collection devices 

deployed from a submersible (Cordes et al. 2008). Photographic surveys indicate that a variety of 

invertebrate and fish species occur primarily and possibly exclusively in these habitats (Ross and 

Quattrini 2007, Lessard-Pilon et al. 2010). Some associated species appear to have very specific 

interactions with L. pertusa including the polychaete Eunice sp. which may help to assemble coral 

structure and the coralivorous gastropod Coralliophila sp. (Cordes et al. 2008; Becker et al., 2009). 

From previous L. pertusa community collections in the GoM, it is thought that depth and the 

relative proportions of live and dead coral are the primary variables that structure L. pertusa

communities. Depth has been shown to be the most significant variable in numerous community 

studies in the deep sea, and in the GoM in particular (Cordes et al. 2008, Pequegnat 1990). 

However, this trend appears to only hold true within a given habitat type, with significant 

differences found between tube worm and mussel communities at seeps (Cordes et al. 2009) and 

tube worm and coral communities from the same sites (Cordes et al. 2008). The significance of 

depth of collection to community structure may be due to a variety of environmental factors that 

co-vary with depth. These factors, including temperature, pressure, dissolved oxygen 

concentration, water mass, and aragonite saturation state, may exert a wide variety of effects on 

the physiology of the species composing the communities at coral sites and may restrict their 

bathymetric ranges. 

In this section we present the results from four approaches based on imagery and physical 

collections used to gain a better understanding of the community structure, biodiversity and 

biogeography of deep-water coral communities in the GoM. The first approach was to use 

photographic transects (from AUV surveys and randomized parallel ROV transects) to collect data 

at the largest scale possible within areas of sites supporting coral growth. This technique provides 

the best data on density of corals and other fauna within sites with abundant coral growth over 

large areas, but was not useful to describe coral communities at deep water sites where coral 

occurrence was very patchy on carbonate boulders and outcrops. A second approach also used 
117

imagery, but in this case employed construction of photomosaics from imagery taken over 

haphazardly chosen smaller areas within a site, where numerous coral colonies could be imaged 

in areas of 10 – 100 m2. A third approach used quantitative collections of the communities 

associated with the scleractinian corals L. pertusa and M. oculata. Data collected with this 

approach was interpreted in conjunction with data from previous studies (Cordes et al., 2008; 

2009) using the same equipment and approach. The fourth approach analyzed only the fauna that 

may be considered symbiotic with corals: the “coral associates” that are attached to or live on the 

corals.

4.1 INSIGHTS INTO COMMUNITY STRUCTURE, BIODIVERSITY AND BIOGEOGRAPHY 

FROM ANALYSIS OF LARGE-SCALE PHOTOTRANSECTS

4.1.1 Introduction

This component of the project examined Lophelia pertusa communities at three of the study sites 

(VK826, VK906, and GB535) on the Northern GoM continental slope. Photographic surveys were 

used to establish live-to-dead ratios and differences in megafauna for the communities and the 

community-wide abundance of associated fauna. The sites surveyed had a depth range of 390 to 

551 m with a slope range of 0 to 22.8°. GB535 had a slope of 2.8° along the track of the survey 

and was the deepest of all the sites during the investigation with a depth range of 508 to 551 m. 

VK906 had the largest range of depth from 490 to 471 m. This also featured the greatest slopes of 

all the surveyed sites with a range of 12.4 to 22.8°. VK826 had a depth range of 459 to 483 m and 

a slope that ranged from 0 to 14°. 

4.1.2 Methods

4.1.2.1 Field Methods

A photographic survey of VK826 (Table 4-1) was collected during August and September of 2009 

on the R/V Brooks McCall. The survey was completed with the AUV Sentry equipped with a 

Prosilica 1380C camera (pixel dimensions 1360 by 1024, acceptance angles 43° horizontal and 

vertical) with a Schneider-Kreuznach Cinegon 8 mm lens over a route plotted to collect photos of 

the L. pertusa community below (Figure 4-1A). The photographs were downloaded from the 

camera to an external hard drive and given file names corresponding to time, date, and photograph 

number to facilitate geo-reference for the images. The area selected for the AUV survey was 

located within the Viosca Knoll block 826 (VK826), targeting the major portion of the reef as it 

was known at that time (Schroeder, 2002). The average altitude for the AUV was 6.68 m. 

A second cruise, on R/V Ronald H. Brown, during October and November of 2010, used the Jason

II ROV surveyed coral communities over random transects that targeted known L. pertusa

communities in VK906, GB535, and a different region at the VK826 site with dense coverage of 

L. pertusa that had been discovered after the 2009 work (Figure 4-1A-C). The average altitude for 

the ROV survey was 4.74 m. The photographic surveys collected by the Jason II, used a Nikon 

E995 camera (pixel dimensions 2048 by 1536, acceptance angles 54° horizontal, 48° vertical) in a 

Scorpio underwater housing. Images were stored as jpeg files using the date-time naming 

convention. The survey regions were rectangular regions of 200 x 200 m or 250 x 250 m positioned 
118

in areas known to contain corals. Prior to beginning the survey, a series of 100-m long transects 

were chosen at random within the survey area (MacDonald et al., 2010). 

Table 4-1.

Summary of photographic samples taken at each site including the number of 

photographs and total area in meters of the area surveyed. 

Figure 4-1. Map of regions surveyed using the AUV and ROV. VK826 in 2009 and 2010 (A), 

VK906 (B), and GB535 (C). Transects from 2010 are denoted by green (starting) and red 

(stopping) markers.

Site* Year Depth (m) Latitude Longitude Photographs Photographs with Coral Total Area (m2)

VK826 2009 436-542 29 9.5214 N 88 1.368 W 1331 271 33029

VK826 2010 501-546 29 9.2708064 N 88 1.368 W 71 33 851

VK906 2010 383-465 29 4.251 N 88 23.208 W 168 13 2013

GB535 2010 497-535 27 25.6872444 N 93 34.52 W 191 0 2288

* Site names are taken from lease block numbers (See Figure 4-1).
119

4.1.2.2 Analytical Methods

The photographs were reviewed in detail to determine the presence of L. pertusa, other cnidarians 

and other visible megafauna. When a photograph was found to contain images of L. pertusa, the 

file was analyzed in ImageJ, an image processing program (Burger, 2009), to measure the total 

area cover of coral, both live and dead. The area of live and dead coral was measured by selecting 

the perimeter of the coral. The total area of both types of coral was selected and measured, followed 

by the measurement of the live region of the corals. The dead area was determined by subtracting 

the live portion of coral from the total amount of coral. These measurements were first collected 

as the number of image pixels within a perimeter. The scale of the pixels, and the estimated area 

of coral regions (in m2), was calculated from the horizontal and vertical pixel dimensions of the 

photographs (ph, pv), horizontal and vertical acceptance angle of the camera lens (h, v) and the 

altitude of the camera (α) for each photograph (1). 

horizontal pixel scale = 2(tan α

h

2

)/ph and vertical pixel scale = 2(tan α

v

2

)/pv (1)

The ratio was established by dividing either the live or dead coral by the total amount of coral. 

Then the percentage was converted to decimals to be used for obtaining the area in m2of corals in 

the photographs. Fauna at all sites were identified to the nearest practical taxon (Table 4-2). 

Unidentified taxa comprised 132 individuals in 9 separate groups and are not listed. Faunal 

diversity was quantified using the Shannon-Weiner index and all the sites were compared using a 

Bray-Curtis similarity index based on presence-absence. Total sampling effort for rarefaction was 

calculated from the area covered in the photographs. Live to dead ratios were compared among 

surveys by applying a t-test to the mean values in the photographs.
120

Table 4-2.

Mobile and sessile fauna observed in photographic transects at three study sites. 

Taxa VK826 (2009) VK826 (2010) VK906 (2010) GB535(2010)

Porferia

 Porferia spp. 2

Cnidaria

 Actinoscyphia saginata 30 3 76

 Actinoscyphia sp. 1 13 1 9

 Actinoscyphia sp. 2 24

 Actinoscyphia sp. 3 17

 Actinoscyphia sp. 4 5

 Actinoscyphia sp. 5 13

Cnidaria: Solitary corals

 Callagorgia americana 4

 Gorgonacea sp. 5

 Leiopathes sp. 54 3 26

 Stichopathes sp. 30

 Unid coral 20 1

Annelida: Polychaeta

 Lamellibrachia sp. 9 1

 Serpulidae sp. 1

 Unid polychaete 1 1

 Unid polychaete 2 3

Mollusca: Cephalopoda

 Unid squid 3

Arthropoda: Crustacea

 Bathynectes longispinia 4 1 4

 Bathynomous giganteus 1 1
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Table 4 2. Mobile fauna observed in photographic transects at three study sites. (continued).

Taxa VK826 (2009) VK826 (2010) VK906 (2010) GB535(2010)

 Chaceon fenneri 14 1 3

 Eumunida picta 41 17 6

 Eumunida sp. 1 1

 Eumunida sp. 2 2

 Pleoticus robostus 1 7

 Systellaspis pellucida 5

 Rochinia crassa 1 2 1

Arthropoda: Pycnogondia

 Pycnogonida sp. 1 4

 Pycnogonida sp. 2 2

Echinodermata

 Asterioda spp. 1 25 3 7

 Asterioda spp. 2 11

 Brisingida sp. 1

 Centrostephanus longispinus rubricgulus 14

 Comactinia meridionalis hartlaubi 3

 Echinoidea spp. 1 82

 Echinoidea spp. 2 4 1

 Luidia sp. 7 1

 Novodinia antellensis 7 4

 Ophiuroidea sp. 3

 Stylocidaris affinis 20 2

 Tethyaster grandis 8 1

Chordata: Actinopterygii

 Cephalopholis cruentata 5

 Gephyroberyx darwinii 1

 Chaunax suttkusi 1

 Hoplpstethus atlanticus 39

 Hyperglypha perciformis 25 3 1 2

 Prionotus paralatus 2

 Synodus sp. 31

 Urophycis cirrata 57 5 19 7

 Nezumia aequalis 1

Chordata: Chondrichthyes

 Unid shark 1 1

Chordata: Sirenidae

 Psuedobranchus sp. 16
122

4.1.3 Results 

4.1.3.1 Live-to-Dead Ratios

Summary results for the live-to-dead ratio of corals observed at the three sites are shown in Figure 

4-2. The AUV survey at VK826 in 2009 comprised an area of 33,029 m2; 96% of the area surveyed 

had no coral cover. The total area of living and dead corals was 1,289 m2. The live-to-dead ratio 

was 0.241. The average amount of coral framework coverage per photograph containing coral was 

4.74 m2 with 0.72 m2being live coral. The ROV transects at VK826 in 2010 covered 851 m2. The 

photographs revealed 67% of the area containing no coral coverage. The total area of coral was 

280 m2. The live-to-dead ratio was 0.137. The photographs containing coral had an average of 8.48 

m2of coral with 1.64 m2of the coral being live. The ROV photographic transects at VK906 in 

2010 covered an area of 2013 m2. The photographs showed no coral coverage for 97% of the area. 

Total coral coverage was 53 m2. The live-to-dead ratio was 0.131. The photographs containing 

coral had an average of 4.41 m2 of coral with 0.30 m2being live. The live-to-dead ratios observed 

in the VK826 site in 2009 were significantly greater than observed in another area of VK826 in 

2010 (T-test of means, P < 0.05). However there was not a significant difference in the live-todead ratio observed during the 2010 surveys of VK826 and VK906, respectively (T-test of means, 

P > 0.95). The survey transects at GB535 covered an area of 2288 m2. The photographic survey 

at this site resulted in no coral cover observed. 

Figure 4-2. Average percentage of live coral cover observed at project sites VK826 and 

VK906 (None observed at GB535). The 2009 and 2010 results are for surveys of 

different regions of the VK826 site. See Figure 4-1 for detail.
123

4.1.3.2 Description of Communities 

Both areas at Viosca Knoll 826 included large coral mounds that are 5 m wide and a minimum of 

1 m tall. These mounds were comprised largely of dead coral matrix that contained sediment and 

resident mobile fauna. The tips of branches were generally where the living (white) coral was 

found. The large colonies formed sub-circular terraces across the slope. In the densest areas of 

mounds, the terraces were almost contiguous. The large mounds were surrounded by coral rubble 

and small living communities. Most pieces of rubble were just a few centimeters in length. The 

coral rubble had signs of sediment accumulation in the rubble. Some of the rubble had patches up 

to 0.5 m in diameter of bacterial mats growing on them; the mats were grey, light brown, and white 

in color. These mounds had mobile fauna hiding in the dead coral matrix as well as on top of the 

living material. Crustaceans (Eumundia picta) and urchins were seen on top of the living coral, 

while fish were observed inside the dead coral matrix. Filter-feeding associates were not generally 

seen on the largest coral banks. 

The profile of a typical large carbonate terrace would have a scattering of dead and broken mussel 

shells at the base than a steep rise of 0.5 to 2.5 m. At the upper edge of the rise, and extending onto 

flat portion of the outcrop, large, closely spaced colonies of the sea fan Callagorgia americana

were often seen as were colonies of Leiopathes glaberimma. Mounds smaller in size, 2 m in 

diameter, were also seen throughout the site. These mounds were similar to the larger mounds with 

their construction. They were solitary and had rings of coral rubble around them. Unlike the larger 

mounds, they had filter-feeders attached to the coral matrix along with mobile fauna. 

Other areas of the site contained small communities of Lophelia of 0.5 m in diameter that were 0.5 

to 1 m apart. These communities were attached to visible carbonate substrate and had anemones 

and serpulidids nearby or attached to the same substrate. These areas were towards the edges of 

the reef community and had a scattered trail of coral rubble leading to them from the mounds 

above. Anemones were settled randomly in patches of up to 5 per m2along this rubble field. The 

bottom-most part of the slope surveyed had sediment that consisted mainly of clay that contained 

tens of burrows per photograph with fauna tracks in every direction and pockmarks throughout. 

This area contained no coral rubble and very little life was visible, although tracks were all over 

the area. 

Viosca Knoll 906 had coral mounds, up to 2 m in diameter, at the highest point of the survey. 

These mounds were similar to ones of a similar size at VK826. The mounds were mainly 

constructed of a dead coral matrix with living tips at the top of the mound. The dead coral matrix 

was home to filter feeders and soft coral. Crustaceans, fish, and urchins also called the matrix 

home. The living coral material, which became as large as 0.5 m2patches, had crustaceans and 

urchins on it. Around the mounds, areas of high coral rubble fields were colonized by anemones, 

octocorals, and black corals. The rubble in most cases has sediment, most likely silts and sands, 

covering it partially. This dense field of coral rubble had many crustaceans, enchinoderms, fish, 

and urchins throughout. The corals and anemones were seen in densities of up to 5 per m2. 

Continuing down the slope, the amount of coral rubble decreased. More of the clay sediment of 

the seafloor became visible, while the coral rubble appeared to have more coarse sediment on and 

directly around it. The rubble was colonized by anemones and red Leiopathes glaberrima, but in 

lower abundance than the higher coral rubble area up slope. At the deepest portion of the survey 
124

area, the rubble disappeared and the seafloor sediments were visible. This area contained burrows, 

pockmarks, and tracks of mobile faunal throughout. This area was sparsely colonized by sea fans 

and anemones. All the mobile fauna seen in the shallower portion of this site were also observed 

here with the addition of polychaetes. The Venus flytrap anemone (Actinoscyphia saginata) and 

an unknown species of anemone were observed singly and in groups among the soft sediments of 

the deeper portion of the VK906 site. 

No coral mounds were seen in the Garden Banks 535 random photographic transects. Living 

corals were, however, observed elsewhere in the overall area. The survey documented several 

patches of coral rubble among the carbonate outcroppings. The rubble was dead material with little 

sign of sedimentation unlike the other sites at Viosca Knoll. The patches were around 2 m in 

diameter and had gorgonians on the rubble. 

The majority of the site was stretches of fine sediments with intermittent carbonate outcroppings 

(>1 m diameter). The sedimented areas feature numerous burrows, pockmarks and lebensspuren 

like the other sites. Crustaceans and fish were seen throughout the clay areas. The areas containing 

the carbonate outcroppings generally had octocorals and demosponges, from the family 

Coralistidae. One of the areas featured a grey bacterial mat with a white outer edge. The 

demosponges were up to 0.5 m in diameter. A few of demosponges also had crustaceans on or near 

them.

One large carbonate platform greater than 3 m in width was seen and had several demosponges on 

its surface. An area containing small, less than one meter carbonate outcroppings had the remnants 

of a mussel bed scattered throughout. This mussel bed was similar to the one observed at other 

sites with partially buried and degraded shells, although some of the shells had soft corals attached 

to them. 

4.1.3.3 Mobile Fauna

The mobile fauna observed in the photographs presented in a number of different modes. The 

crustaceans had a tendency to be hidden in or on the coral mounds and by other filter feeders. 

Some fauna were easily visible resting over the sediment, while under the coral mounds, only the 

tails of some fish could be seen. Sixty different taxa were observed from the transect photographs 

(Table 4-2). Each survey contained between 15 and 35 taxa (identified to the lowest practical 

taxon). A previous study measured species diversity on Lophelia reefs offshore Norway and found 

Shannon-Weiner diversity index value of 5.50 (Jensen and Frederiksen, 1992). Values for the reefs 

surveyed during the present study ranged from 1.75 to 3.01. The similarity of species for VK826 

in 2009 to 2010 was 62.84 using a Bray-Cutis similarity index. VK826 in 2009 and 2010 had 

similarities to VK906 of 65.03 and 64.21. GB535 had a similarity of 58.86 to VK826 in 2009 and 

62.09 in 2010. The similarity to VK906 was 54.75. Rarefaction curves (number of new species 

per individual sampled at each site) for species richness (Figure 4-3) showed a tendency to level 

off after 80 to 500 samplings. The VK826 survey in 2009 encountered the most species (35) and 

individuals (556). The 2010 survey at VK826 found fewer species (18) and individuals (89), and 

all of the species had been seen in the previous year. VK906 had 27 different species and 302 

individuals, while GB535 had 15 species and 62 individuals. 
125

Figure 4-3. Rarefaction curves for photographic sampling of mobile fauna observed in 

photographic transects at three project sites: A, VK826 (2009); B, VK826 (2010); C, 

VK906; D, GB535.

4.1.4 Discussion

In regions where Lophelia pertusa are known to be abundant, L. pertusa colonies, including living 

and dead cover a small fraction of the total bottom area (4.25±15.5%). The L. pertusa

communities’ live-to-dead ratio shows that 1/4 or less of the surface area of coral substrate contains 

living colonies. These results record the current status of the coral communities surveyed on the 

Northern GoM continental slope, and can be used as a baseline to study the possible long-term, 

sub lethal effects from the DWH oil spill on the surveyed communities. No immediate damage 

from the DWH oil spill was apparent at VK826 in the live-to-dead ratios from 2009 to 2010.

The difference in live to dead coral cover observed during the different surveys probably reflects 

the different survey methods and the areas targeted. The dive tracks for the AUV/ROV are 

different for the two years. A regular grid, covering a major portion of the reef in that part of the 

site, was used in 2009, while the 2010 transects were placed randomly over a different 250 X 250 

meter area chosen because of high L. pertusa density in that area. (MacDonald et al., 2010). 

Consequently, the 2009 survey found a much smaller fraction of the total survey area with coral 

cover than any of the 2010 surveys that observed corals. The fact that the live to dead ratios 

observed in the 2010 surveys for VK826 and VK906 were significantly lower than in the 2009 
126

survey probably reflects local differences within the larger reef area. Another factor with the 

potential to affect the live to dead ratio is the age of the reef and time over which dead L. pertusa

has accumulated or the rate at which local sedimentation buries the non-living coral framework. 

The decreasing number of taxa can also be seen comparing VK826 to VK906 and for GB535. 

Even accounting for sampling differences, increases in depth and proximity, moving away from 

the Mississippi River outfall, are reflected in decreases in meiofaunal biomass (Baguley et al., 

2006). Certain taxa found at Viosca Knoll maybe more adapted for a higher nutrient environment 

(Cordes et al., 2008), explaining why there is the shift in taxa from Viosca Knoll to the Garden 

Banks block. The rarefaction curves (Figure 4-3) leveled off between 80 and 500 samplings, which 

indicate that additional sampling would not have yielded substantially more taxa among the 

associated fauna. The rarefaction curve for the GB535 site showed the least tendency to reach an 

asymptote. Taxa richness was lowest at the GB535 site as well, with almost 50% (30) of the 

individuals captured represented by a single taxon. The difference seen in the taxa at VK826 site 

between 2009 and 2010 is likely due to the high number of photographs reviewed for the 2009 

survey, which covered almost the entire south western portion of the reef while the 2010 transects 

covered a smaller more concentrated portion of the north east corner of the reef. 

4.2 INSIGHTS INTO COMMUNITY STRUCTURE, BIODIVERSITY AND BIOGEOGRAPHY 

FROM ANALYSES OF PHOTOMOSAICS

4.2.1 Introduction

A total of 22 photomosaic stations were established in 12 different study sites. Nine of these were 

only photomosaicked in one year of the project and 13 of them were imaged during cruises on the 

Ronald H. Brown in both2009 and 2010. These sites were established with three primary goals in 

mind. The first was to allow comparison between different study areas and across depths using 

quantitative data of characteristic communities from that site. The second was to begin to 

investigate temporal change in these communities. Since the images were collected only two years 

apart, it is too early for robust growth estimates or to see significant changes in the slow growing 

colonial coral populations; however, comparisons between years provide preliminary information 

on the stability of the attached fauna and the fidelity of the mobile fauna. The third was to establish 

baseline stations to follow temporal change over longer time periods and to monitor for 

anthropogenic impact. BOEM’s foresight in establishing these stations was evident after the DWH

blowout, when the first deepwater megafauna stations chosen for investigation by the NRDAt 

effort were our study sites at VK906, VK826, and MC751. An attempt was also made to revisit 

the site first established during the Lophelia I project in VK862. Lack of high-quality navigation 

during the Lophelia I project prevented finding and re-occupying that site. However, the stations 

established during the 2009 Ron Brown cruise were re-occupied within weeks of the capping of 

the Macondo well, and new mosaic stations were established in VK862. All of these and most 

others established in 2009 were revisited during the 2010 Ron Brown cruise for comparison to the 

pre-spill mosaics.
127

4.2.2 Methods

4.2.2.1 Selection of Areas for Mosaics

A total of 22 areas were chosen for mosaics in 12 of the sites selected for this project (Table 4-3). 

The areas were not chosen randomly, but rather selected because of the presence of corals, usually 

associated with a single boulder or carbonate outcrop. In order to obtain sufficient resolution in 

downlooking images to meet the goals for this aspect of the project, it was necessary to collect the 

images from an altitude of less than 5 m. This limited the total area that could be included in a 

mosaic, and as a result, a primary criterion in selection of areas for mosaics was a relatively high 

density of colonial corals. A second first order criterion was practical; local topography had to 

allow an ROV to maintain a fairly constant altitude over the area. Since a primary focus of the 

project was the coral Lophelia pertusa, we focused on areas that included this coral if it was present 

at the site being studied. When a site was characterized by the presence of different corals or 

mixtures of corals, areas with high densities of the corals typical for the site were chosen. After 

an area was chosen to mosaic, a marker was deployed to facilitate re-occupation of the site and to 

provide a check for scale calculations from navigation and lasers. Location of the marker was 

determined using USBL navigation averaged over the time the ROV spent working in this area. 
128

Table 4-3. 

Photomosaic designations, locations, visit dates, and areal extents

Station 

name

Site Date imaged (YYYYMM-DD) Dive Area 

(m2)

Depth 

(m) Latitude Longitude

A AT047 2009-08-24 J2-457 39.5 839 27.8803 89.7887

B GB299 2009-08-27 J2-459 55.5 360 27.6865 92.2308

B GB299 2010-10-20 J2-530 39.0 360 27.6865 92.2308

C GB535 2009-08-28 J2-460 39.2 516 27.4280 93.5835

C GB535 2010-10-20 J2-531 53.6 516 27.4280 93.5835

D GB299 2009-08-26 J2-459 75.9 359 27.6865 92.2310

D GB299 2010-10-20 J2-530 57.7 359 27.6865 92.2310

E GB535 2009-08-28 J2-460 8.6 520 27.4271 93.5854

E GB535 2010-10-21 J2-531 41.6 520 27.4271 93.5854

G MC751 2009-09-01 J2-464 34.3 441 28.1937 89.7987

G MC751 2010-10-27 J2-536 77.1 441 28.1937 89.7987

H1 MC751 2009-08-31 J2-464 52.4 441 28.1940 89.7983

H1 MC751 2010-10-26 J2-536 23.8 441 28.1940 89.7983

H2 MC751 2009-09-01 J2-464 29.7 441 28.1940 89.7983

H2 MC751 2010-10-26 J2-536 30.2 441 28.1940 89.7983

J VK906 2009-09-02 J2-465 30.4 389 29.0697 88.3771

J VK906 2010-10-24 J2-534 63.0 389 29.0697 88.3771

L VK906 2009-09-02 J2-465 54.9 394 29.0693 88.3776

L VK906 2010-10-24 J2-534 60.1 394 29.0693 88.3776

M VK826 2009-09-03 J2-466 43.2 470 29.1581 88.0169

M VK826 2010-10-16 J2-526 29.7 470 29.1581 88.0169

N VK826 2009-09-03 J2-466 51.7 476 29.1578 88.0163

N VK826 2010-10-16 J2-526 39.6 476 29.1578 88.0163

O VK826 2009-09-04 J2-466 39.1 463 29.1648 88.0116

O VK826 2010-10-31 J2-540 108.7 463 29.1648 88.0116

Q VK826 2009-09-04 J2-467 48.8 479 29.1587 88.0105

Q VK826 2010-11-01 J2-540 78.3 479 29.1587 88.0105

R VK862 2010-10-26 J2-535 38.5 317 29.1063 88.3842

T VK862 2010-10-26 J2-535 53.0 310 29.1067 88.3843

T1_T2 MC118 2010-10-30 J2-538 25.5 884 28.8527 88.4927

U MC885 2010-10-17 J2-527 26.4 633 28.4733 89.7171

V/M1 GC354 2010-10-19 J2-529 20.9 526 27.5979 91.8264

W GC140 2010-10-22 J2-532 184.9 254 27.8105 91.5370

X MC118 2010-10-30 J2-538 50.2 883 28.8527 88.4925

Y VK906 2010-10-25 J2-535 58.9 395 29.0690 88.3777

AA MC338 2010-11-03 J2-541 307.3 1371 28.6722 88.4765

5 GC852 2009-08-29 J2-461 38.7 1400 27.1098 91.1661

4.2.2.2 Image Collection

Downlooking images were acquired with a Nikon E995 digital still camera in a pressure housing 

mounted on the ROV Jason II, operated from the NOAA Ship Ronald H. Brown. Illumination was 

provided with a combination of an hydrargyrum medium-arc iodide lamp light, one or two light-
129

emitting diode (LED) arrays and a 300 Watt per second strobe, used as appropriate in different 

terrains, altitudes, and with different color subjects. Down-pointing parallel lasers spaced 30cm 

apart provided a scale reference internal to each image.

The ROV was maneuvered into one corner of the area to be mosaicked and camera/strobe setting 

optimized for this location. During collection of the imagery, navigation was accomplished using 

a closed loop system with a Doppler-velocity navigation stream so the pilot was not flying with 

the control stick, but rather entering movements digitally. The vehicle heading and altitude was 

held constant during each mosaic and between years for the same site. The pilot would enter a 

move (distance) and velocity that allowed collection of a series of overlapping images at the set 

heading and altitude, and pictures were obtained with approximately 50% overlap between images. 

At the end of a line, the pilot would enter a lateral move leaving 50% overlap with the previous 

line and move in reverse an equal distance, ending up with a 50% lateral overlap with the first 

image. The pilot would again move the ROV laterally and repeat this process until the subject 

area had been covered with overlapping parallel strips of images. Each image was associated with 

geographic coordinates from the Doppler velocity navigation stream which normally remained 

accurate to within a few cm over the course of image collection for an individual mosaic.

Due to variability in conditions at the different monitoring stations, such as turbidity and required 

altitude to avoid damage to the site, the quality of images varied somewhat between sites and dives. 

However, images were normally sufficient to identify organisms and objects down to about 1-2 

cm in size.

In addition, four stations were established with mosaics imaged from a side-looking perspective. 

These were analyzed qualitatively and not digitized.

4.2.2.3 Creation of Mosaics

Images used in the construction of mosaics were selected for clarity and with a minimum of 20% 

overlap between subsequent images in a line. The images collected in 2009 were assembled into 

strips using an algorithm (Pizarro and Singh 2003) implemented as a script in MATLAB version 

2010B (Mathworks 2010) and then the strips were manually stitched together into the final mosaic 

with the Photomerge tool in Adobe Photoshop CS3 (Adobe 200x). Increases in computing power 

and improvements in the code allowed images collected in 2010 to be assembled into the final 

mosaics with the Pizarro and Singh (2003) algorithm implemented as a script in MATLAB version 

2010B (Mathworks 2010) (See section 4.2.3.1). The resulting mosaic was geo-referenced using 

coordinates from the center of two images in opposite corners of the mosaic using a geographical 

information system (GIS) implemented in ArcGIS 10.1 (ESRI 2012) and a projected coordinate 

system using WGS84 datum. 

4.2.2.4 Digitizing Mosaics

All fauna in each mosaic were identified to the lowest possible taxonomic level and together with 

biological substrates were digitized to allow quantitative analysis of the communities and 

comparisons among the mosaics (See Section 4.2.3.1). Colonial cnidarians, tube worms, 

encrusting sponges, and areas of dead coral skeletons were digitized as polygons for analysis as 

potential biological substrates as well as to record presence and location within the mosaic. 
130

Polygon categories included live and dead Lophelia pertusa, live and dead Madrepora oculata, 

Callogorgia sp. (and one dead Callogorgia sp.), Paramuricea spp., Paragorgia spp., Antipathes 

spp., Leiopathes spp., Stichopathes spp., Swiftia pallida, Isididae spp., Muriceides cf. hirta, 

Clavularia rudis, Acanthogorgia aspera, sea pens, other antipatharian corals, unidentified corals, 

tube worms, encrusting sponges, and hydroids. Solitary fauna were digitized as points, and 

included five types of crabs, six anemones, four types of sea urchins, whip corals, brittle stars, 

mussels, clams, giant isopods, individual sponges, crinoids, 11 types of fish, eight types of sea

stars, and sea cucumbers. Location-based queries were used to determine the distribution of the 

solitary fauna across each of the potential substrata (polygons). 

4.2.2.5 Georeferencing between Years 

To compare 2009 and 2010 digitized mosaics, a geographic transformation was applied to the 2009 

mosaics to allow the two years to be superimposed upon each other. This was necessary due to 

slight differences in the altitudes and exact placement of the lines run during image collection in 

the two years. The geographic transformation used a minimum of 10 coincident control points on 

each mosaic. The coincident control points were used to “spline” the 2009 mosaic to best match 

the 2010 mosaic. The geographic “spline” transformation locks the source control points to the 

target control points, and forces the raster pixels between control points to warp. Since the original 

digitized “vector polygons” could not be directly transformed, the polygons were rasterized before 

applying the geographic transformation. The transformed raster was converted back to vector 

polygons for quantitative analysis with the overlapping 2010 polygons. In most cases this process 

resulted in minimal warping of the 2009 image; however, in a few cases, obvious warping of the 

2009 image was evident after the transformation (i.e., mosaic at marker J in VK906, 
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Figure 4-12). For the comparisons between years, only the overlapping areas of each mosaic that 

were mosaicked in both years were used, and all differences noted in automated analyses were 

hand checked to original images.

4.2.2.6 GIS and Statistical Comparisons

Diversity was assessed as standardized species richness (calculated as the number of species 

present within a mosaic divided by the area of the photomosaic), as well as the Shannon diversity 

index (natural log scale), Simpson’s diversity index (1 – λ’), and Pielou’s evenness index, using 

all organisms that could be enumerated in the images (excluding polygons). The Shannon and 

Simpson’s diversity indices and Pielou’s evenness index were calculated using the DIVERSE 

application in PRIMER 6/ PRIMER-E (Clarke and Warwick 2001).

Similarities in community composition between photomosaic sites and between years were 

calculated using the Bray-Curtis similarity index in PRIMER 6 (PRIMER-E 2009) after fourthroot transformations. Presence/absence data was also used to analyze both solitary and aggregated 

fauna (Cordes et al., 2006, and references therein). Non-metric Multi-Dimensional Scaling 

(nMDS) ordination and average linkage cluster analyses were used to examine similarities among 

community compositions of the photomosaic sites. Chi-square analyses tested whether there were 

significant associations between point fauna and substrata within selected photomosaic sites.

4.2.3 Results and Discussion

4.2.3.1 Summaries of Photomosaics of Coral Communities

Below are summaries of all mosaics constructed from images collected over the course of this 

project. All are associated with physical markers and their locations are well navigated. Most have 

been visited and re-mosaicked at least once. Below each verbal summary is a low-resolution image 

of the mosaic and its digitized version. All digitizations use the same key (Figure 4-4). The full 

resolution versions of each mosaic, with both the original and re-georeferenced versions of the 

2009 mosaics are in Appendix C-2 and C-3.
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Figure 4-4. Key for all digitized photomosaics in this section (4.2.3.1).

4.2.3.1.1 GC140: Mosaic Marker W, 2010 (only)

This site is located at 27.81052 ̊N 91.53705 ̊W at a depth of about 254 m. Images for the mosaic 

were collected on dive J2-532 on 10/22/10. The mosaic covers an area of approximately 185 m2. 

This mosaic features a large carbonate rock outcropping covered in black and bamboo corals. A 

few Stichopathes sp. and Paramuricea sp. are also found at the site along with some unidentified 

corals. Individual and encrusting sponges can be seen distributed across the site. Mobile fauna 

include seven anemones, two Epinephelus niveatus fish, two Hoplostethus occidentalis fish, and 

33 ophiuroids. 
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Figure 4-5. Photomosaic of Marker W in 2010 and digitization of this mosaic.

4.2.3.1.2 VK862: Mosaic Marker R, 2010 (only)

This site is located at 29.10635 ̊N 88.38422 ̊W at a depth of about 317 m. Images for the mosaic 

were collected on dive J2-535 on 10/26/10. The mosaic covers an area of approximately 38.5 m2. 

The mosaic centers around a raised outcropping covered in sponges, anemones, Leiopathes sp., 

Callogorgia sp., and Lophelia pertusa. The Lophelia is found on the northern half and additional 

Callogorgia sp. are found to the west of the outcropping. To the north there are more colonies of 

Leiopathes sp. and Callogorgia sp. present. Anemones and sponges surround the outcropping on 

the seabed. The southernmost corner of the mosaic features a large Muriceides sp. colony. Mobile 

fauna at this site include six Hyperoglyphe perciformis fish, ten crabs, one sea star, and 513 total 

anemones.
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Figure 4-6. Photomosaic of Marker R in 2010 and digitization of this mosaic.

4.2.3.1.3 VK862: Mosaic Marker T, 2010 (only).

This site is located at 29.10667 ̊N 88.38426 ̊W at a depth of about 310 m. Images for the mosaic 

were collected on dive J2-535 on 10/26/10. The mosaic covers an area of approximately 53.0 m2. 

Anemones dominant this mosaic and 755 individuals are observed at this site. Isididae and 

Leiopathes sp. are also found here. A shallow cliff is observed going from the western to the 

northern and then eastern edges of the map. Mobile fauna include one Hoplostethus occidentalis 

fish, one Hyperoglyphe perciformis fish, and two urchins.

Figure 4-7. Photomosaic of Marker T in 2010 and digitization of this mosaic.
135

4.2.3.1.4 GB299: Mosaic Marker B

This site is located at 27.68648 ̊N 92.23084 ̊W at a depth of approximately 360 m. The substrate 

in this mosaic is mud and the area is dominated by Callogorgia sp. with a few L. glaberrima, whip 

corals, and Paramuricea sp.

4.2.3.1.4.1GB299: Mosaic Marker B, 2009

Images for the mosaic were collected on dive J2-459 on 8/27/09.The mosaic encompasses a 

roughly rectangular area of about 55.5 m2. Callogorgia sp. is the most abundant coral and is 

observed across the site distributed relatively evenly with slightly less density around the southeast 

and northwest corners. Four Paramuricea sp. and five Leiopathes sp. are also located across the 

site. One hundred sixty-three ophiuroids are observed, the majority of which are in association 

with the Callogorgia sp. Thirteen anemones, seven crinoids, four whip coral, and 60 encrusting 

sponges are found distributed across the site.

Figure 4-8. Photomosaic of Marker B in 2009 and digitization of this mosaic.

4.2.3.1.4.2GB299: Mosaic Marker B, 2010.

Images for the mosaic were collected on dive J2-530 on 10/20/10.The mosaic encompasses a 

roughly square area of about 39.0 m2. Callogorgia sp. are observed across the site distributed 

relatively evenly with less density along the southern edge and northeast corner. One hundred and 

thirty-five ophiuroids are observed on the Callogorgia sp. Four whip coral are also found at this 

site. Mobile fauna include one crab, 11anemones, one Helicolenus dactylopterus fish, 46 urchins, 

and one crinoid.
136

Figure 4-9. Photomosaic of Marker B in 2010 and digitization of this mosaic.

4.2.3.1.5 GB299: Mosaic Marker D

This site is located at 27.68647 ̊N 92.23102 ̊W at a depth of about 359 m. Callogorgia sp. is the 

dominant coral at the site with abundant commensal ophiuroids. 

4.2.3.1.5.1GB299: Mosaic Marker D, 2009.

Images for the mosaic were collected on dive J2-459 on 8/27/09.The mosaic covers an area of 

approximately 75.9 m2. This site is dominated by 82 Callogorgia sp. spread across the area. One 

hundred and thirty-six ophiuroids are found on the Callogorgia sp., the seabed, and one 

Paramuricea sp. One Isididae, one whip coral, and one unidentified coral can also be seen. One 

tube worm, 56 crinoids, 129 anemones, 25 urchins, 26 sea stars, 37 sponges, and one crab are also 

observed at this site. 
137

Figure 4-10. Photomosaic of Marker D in 2009 and digitization of this mosaic.

4.2.3.1.5.2GB299: Mosaic Marker D, 2010

Images for the mosaic were collected on dive J2-530 on 10/20/10. The mosaic covers an area of 

approximately 57.7 m2. This site is dominated by 51 Callogorgia sp. spread across the area. 

Seventy-seven ophiuroids are found on the Callogorgia sp., the sea floor, and one Paramuricea

sp. One sea pen and one whip coral can also be seen. Nineteen urchins, 28 anemones, and one sea 

star make up the rest of the mobile fauna.

Figure 4-11. Photomosaic of Marker D in 2010 and digitization of this mosaic.
138

4.2.3.1.6 VK906: Mosaic Marker J 

This site is located at 29.06967 ̊N 88.37717 ̊W at a depth of approximately 389 m. Large patches 

of Lophelia pertusa takes up the center of the mosaic and are surrounded by dead Lophelia and 

sediment. Substantial colonies of Leiopathes glaberrima are also present at the site.

4.2.3.1.6.1VK906: Mosaic Marker J, 2009

Images for the mosaic were collected on dive J2-465 on 9/2/09. The mosaic encompasses a roughly 

rectangular area of about 30.4 m2. More living and dead Lophelia pertusa are observed along the 

northeast edge of the mosaic. The southwest edge is relatively barren in comparison. A number of 

Leiopathes glaberrima colonies are seen across the mosaic with many concentrated along the 

southern edge of the central Lophelia. Thirty-six crabs are observed clustered on and around the 

live Lophelia. Other mobile fauna at this site include one Gephyroberyx darwinii fish, one 

Nettastomatidae eel, one sea star, 14crinoids, 20urchins, and 12anemones.

Figure 4-12. Photomosaic of Marker J in 2009 and digitization of this mosaic.

4.2.3.1.6.2VK906: Mosaic Marker J, 2010 

Images for the mosaic were collected on dive J2-534 on 10/24/10. The mosaic encompasses a 

roughly rectangular area of about 62.5 m2. The dead Lophelia can be seen across the mosaic. More 

living and dead Lophelia pertusa are observed along the northeast edge of the mosaic. A number 
139

of Leiopathes glaberrima colonies are seen distributed across the mosaic. Mobile fauna at this site 

include 28 crabs, four Hyperoglyphe perciformis fish, one unidentified fish, five sea stars, 

11crinoids, 20urchins, and 18 anemones.

Figure 4-13. Photomosaic of Marker J in 2010 and digitization of this mosaic.

4.2.3.1.7 VK906: Mosaic Marker L 

This site is located at 29.06933 ̊N 88.37759 ̊W at a depth of approximately 394 m. The mosaic 

areas are dominated with mixed live and dead L. pertusa, with numerous colonies of L. glaberrima.

4.2.3.1.7.1VK906: Mosaic Marker L, 2009 

Images for the mosaic were collected on dive J2-465 on 9/2/09. The mosaic covers a rectangular 

area of about 54.9 m2. A patch of Lophelia pertusa lies at the center of the mosaic surrounded by 

dead Lophelia and some Leiopathes sp. to the north and southeast. The rest of the mosaic is mud 

that is sporadically covered in sediment and dead Lophelia pertusa. Mobile fauna at this site 

include five crabs, 12anemones and one urchin. An encrusting sponge is also observed at this site. 
140

Figure 4-14. Photomosaic of Marker L in 2009 and digitization of this mosaic.

4.2.3.1.7.2VK906: Mosaic Marker L, 2010

Images for the mosaic were collected on dive J2-534 on 10/24/10. The mosaic covers a rectangular

area of about 60.1 m2. A patch of Lophelia pertusa lies at the center of the mosaic surrounded by 

dead Lophelia and some Leiopathes sp. to the north and southeast. The rest of the mosaic is mud 

that is sporadically covered in sediment and dead Lophelia pertusa. Mobile fauna at this site 

include 16 crabs, 33 anemones and one urchin.

Figure 4-15. Photomosaic of Marker L in 2010 and digitization of this mosaic.
141

4.2.3.1.8 VK906: Mosaic Marker Y, 2010 (only)

This site is located at 29.06898 ̊N 88.37771 ̊W at a depth of about 395 m. Images for the mosaic 

were collected on dive J2-535 on 10/25/10. The mosaic covers a long rectangular area of 

approximately 58.9 m2. This mosaic features a number of large areas of living Lophelia pertusa

interspersed with dead L. pertusa. Leiopathes sp. is also abundant across the site with highest 

density near the northern and southern edges. Forty-two total anemones are found in this mosaic. 

Other fauna include one Gephyroberyx darwinii fish, one Helicolenus dactylopterus fish, one 

Hyperoglyphe perciformis fish, 32 crabs, four urchins, 27 sponges, one ophiuroid, and two 

crinoids. 

Figure 4-16. Photomosaic of Marker Y in 2010 and digitization of this mosaic.

4.2.3.1.9 MC751: Mosaic Marker G 

This site is located at 28.19366 ̊N 89.79871 ̊W at a depth of approximately 441 m. The primary 

feature seen in this mosaic is a carbonate rock outcropping covered in dead Lophelia pertusa.

Callogorgia sp colonies are also present. Notable at this site is a large clump of vestimentiferan 

tube worms.
142

4.2.3.1.9.1MC751: Mosaic Marker G, 2009.

Images for the mosaic were collected on dive J2-464 on 9/1/09. The mosaic encompasses an area 

of about 34.3 m2. The dead Lophelia pertusa cover about 41% of the total mosaic area. Patches of 

living Lophelia pertusa can be seen in both the center and the North and eastern corners. Six 

Callogorgia sp. are found across the site with 25 associated commensal ophiuroids. Three smaller 

Paramuricea sp. are seen near the center of the mosaic. There are six Muriceides sp. and three as 

yet unidentified corals. The southern corner of the mosaic features a large patch of tube worms. 

Seven urchins, nine crabs, one Moridae fish, one Hoplostethus occidentalis fish, and 45 anemones 

are also observed.

Figure 4-17. Photomosaic of Marker G in 2009 and digitization of this mosaic.

4.2.3.1.9.2MC751: Mosaic Marker G, 2010

Images for the mosaic were collected on dive J2-536 on 10/27/10. The mosaic encompasses an 

area of about 77.1 m2. Areas of living Lophelia pertusa can be seen most notably in the center and 

eastern corner. Callogorgia sp., Paramuricea sp., and Muriceides sp. are found across the site 

along with an as yet unidentified coral species. Sponges are also present. Twenty-eight ophiuroids 

are found on the various corals. The southern corner of the mosaic features a large patch of tube 

worms. Four urchins, ten crabs, and 17anemones are also observed.
143

Figure 4-18. Photomosaic of Marker G in 2010 and digitization of this mosaic.

4.2.3.1.10 MC751: Mosaic Marker H1

This site is located at 28.19404 ̊N 89.79831 ̊W at a depth of approximately 441 m. An elevated 

outcropping is in the center of the mosaic surrounded by tube worms and mixed dead and live 

Lophelia pertusa. In some cases the L. pertusa is very closely intermingled with the tube worms.

4.2.3.1.10.1 MC751: Mosaic Marker H1, 2009

Images for the mosaic were collected on dive J2-464 on 9/1/09. The mosaic encompasses an area 

of about 52.4 m2. In addition to the carbonate outcropping dominating the center of the mosaic, 

part of another outcropping can be seen in the northwest corner of the mosaic. Live Lophelia

pertusa is found among the dead Lophelia pertusa. Paramuricea sp. and Callogorgia sp. are also 

found at this site. Forty sponges, one sea star, 42 mussels, eight crabs, two Helicolenus 

dactylopterus fish, 13brittle stars, and four anemones are also observed. The vast majority of all 

fauna at this site is clustered around the outcroppings with the exception of the Callogorgia sp. 

and their associated ophiuroids. 
144

Figure 4-19. Photomosaic of Marker H1 in 2009 and digitization of this mosaic.

4.2.3.1.10.2 MC751: Mosaic Marker H1, 2010

Images for the mosaic were collected on dive J2-536 on 10/26/10. The mosaic encompasses an 

area of about 23.8 m2. Another outcropping can be seen in the northern corner of the mosaic. Live 

Lophelia pertusa is found among the dead Lophelia pertusa. Paramuricea sp. and Callogorgia sp. 

are also found at this site. Sponges, 34 mussels, five crabs, one Helicolenus dactylopterus fish, 

one Hoplostethus occidentalis fish, 33 brittle stars, and 28 anemones are also observed. The vast 

majority of all fauna at this site is clustered on the outcroppings with the exception of one large 

colony of Callogorgia sp. near some tube worms and sponges and with associated commensal 

ophiuroids found northeast of the central outcropping. 
145

Figure 4-20. Photomosaic of Marker H1 in 2010 and digitization of this mosaic.

4.2.3.1.11 MC751: Mosaic Marker H2

This site is located at 28.19404 ̊N 89.79831 ̊W at a depth of approximately 441 m. The most 

notable topographical feature of this mosaic is an elevated area covered in sediment in the 

southwest corner of the mosaic. Much of the fauna is concentrated in and around this area. 

Callogorgia sp. is quite abundant. L. pertusa, Paramuricea sp. and vestimentiferan tube worms 

are also present at the site.

4.2.3.1.11.1 MC751: Mosaic Marker H2, 2009

This site is located at 28.19404 ̊N 89.79831 ̊W at a depth of approximately 441 m. Images for the 

mosaic were collected on dive J2-464 on 9/1/09. The mosaic encompasses an area of about 29.7 

m2. A patch of dead Lophelia pertusa lies in the middle of the mosaic and the edge of another 

patch can be seen at the bottom with some live Lophelia pertusa. The most prolific coral at this 

site is Callogorgia sp. Both the Callogorgia sp. and Paramuricea sp. at this location are covered 

in ophiuroids. An individual Muriceides sp. colony is present on the west side of the mosaic. 

Tubeworms are found in the southeast corner of the site. Sponges and hydroids are also present. 

Eleven crabs, one urchin, 65 anemones, and one sea star make up the mobile fauna present at this 

site. 
146

Figure 4-21. Photomosaic of Marker H2 in 2009 and digitization of this mosaic.

4.2.3.1.11.2 MC751: Mosaic Marker H2, 2010.

This site is located at 28.19404 ̊N 89.79831 ̊W at a depth of approximately 441 m. Images for the 

mosaic were collected on dive J2-536 on 10/26/10. The mosaic encompasses an area of about 30.2 

m2. A patch of dead Lophelia pertusa lies in the middle of the mosaic and the edge of another 

patch can be seen at the bottom with some live Lophelia pertusa. The most prolific coral at this 

site is Callogorgia sp. Both the Callogorgia sp. and Paramuricea sp. at this location are covered 

in ophiuroids. Tubeworms are found at the southern edge of the outcropping. A large number of 

encrusting and individual sponges, four crabs, one urchin, seven anemones, and one Hoplostethus 

occidentalis fish are observed.
147

Figure 4-22. Photomosaic of Marker H2 in 2010 and digitization of this mosaic.

4.2.3.1.12 VK826: Mosaic Marker M 

This site is located at 29.15807 ̊N 88.01685 ̊W at a depth of approximately 470 m. The mosaics 

are dominated by a single large clump of mixed living and dead L. pertusa. Several L. glaberrima

are also present around the periphery of the main clump of L. pertusa.

4.2.3.1.12.1 VK826: Mosaic Marker M, 2009 

Images for the mosaic were collected on dive J2-466 on 9/3/09. The mosaic has an area of about 

43.2 m2. The central area of mixed living and dead L. pertusa is surrounded by sea floor composed 

of mud. Four L. glaberrima are also found at this site. Mobile fauna include one urchin, 17 crabs, 

one sea star, one Nettastomatidae eel, and one Helicolenus dactylopterus fish. These fauna are 

found in highest density on and around the L. pertusa.

Figure 4-23. Photomosaic of Marker M in 2009 and digitization of this mosaic.
148

4.2.3.1.12.2 VK826: Mosaic Marker M, 2010

Images for the mosaic were collected on dive J2-526 on 10/16/10. The mosaic has an area of about 

29.7 m2. The Lophelia is surrounded by sea floor composed of mud. Leiopathes sp. coral colonies 

are also found at this site. Mobile fauna include 11urchins, 13 crabs, one sea star, one Hoplostethus 

occidentalis fish, and 38 crinoids. These fauna are found in highest density on and around the 

Lophelia.

Figure 4-24. Photomosaic of Marker M in 2010 and digitization of this mosaic.

4.2.3.1.13 VK826: Mosaic Marker N

This site is located at 29.15807 ̊N 88.01685 ̊W at a depth of about 476 m. The mosaics are 

dominated by a mixed clump of living and dead L. pertusa. Two isolated vestimentiferan tube 

worms are surrounded by the L. pertusa clump.

4.2.3.1.13.1 VK826: Mosaic Marker N, 2009.

Images for the mosaic were collected on dive J2-466 on 9/3/09. The mosaic covers an area of 

approximately 51.7 m2. The middle of the mosaic features both living and dead Lophelia pertusa. 

The dead area spreads from the center of the mosaic to the northeast corner. More Lophelia are 

visible at the south and west edges of the mosaic. The primary substrate is mud and to the south it 

is covered with some sediment and dead coral. Two tube worms and three sponges are found near 

the center of the mosaic. Seven urchins, 12crabs, and 21 crinoids are observed concentrated around 

the Lophelia. Other mobile fauna consist of one Nettastomatidae eel, one Helicolenus 

dactylopterus fish, and two sea stars. 
149

Figure 4-25. Photomosaic of Marker N in 2009 and digitization of this mosaic.

4.2.3.1.13.2 VK826: Mosaic Marker N, 2010

Images for the mosaic were collected on dive J2-526 on 10/16/10. The mosaic covers an area of 

approximately 39.6 m2. The middle of the mosaic features Lophelia pertusa both living and dead. 

The dead area is larger and extends from the center of the mosaic to the northeast corner. More 

Lophelia are visible at the south and west edges of the mosaic. The primary substrate is mud and 

to the south it is covered with some sediment and dead coral. Two tube worms and three sponges 

are found near the center of the mosaic, and nine urchins, one crab, one sea star, and nine crinoids 

are observed concentrated around the Lophelia. Other mobile fauna consist of two Hoplostethus 

occidentalis fish and one Helicolenus dactylopterus fish, and two sea stars. 
150

Figure 4-26. Photomosaic of Marker N in 2010 and digitization of this mosaic.

4.2.3.1.14 VK826: Mosaic Marker O 

This site is located at 29.16484 ̊N 88.01156 ̊W at a depth of about 463 m. Both mosaics are 

dominated by large areas of living and dead L. pertusa although the 2010 mosaic includes a 

substantial area not included in the 2009 mosaic.

4.2.3.1.14.1 VK826: Mosaic Marker O, 2009

Images for the mosaic were collected on dive J2-466 on 9/4/09. The mosaic is roughly square 

shaped with an area of approximately 39.1 m2. Dead and living Lophelia pertusa cover the 

southwestern half of the mosaic with living Lophelia concentrated in the center and the southern 

corner of the map. One sea star, 22 crabs, three urchins, and 32 crinoids are found around the 

Lophelia. Four Helicolenus dactylopterus fish and three Nettastomatidae eels are observed along 

with one squid swimming over the site.
151

Figure 4-27. Photomosaic of Marker O in 2009 and digitization of this mosaic.

4.2.3.1.14.2 VK826: Mosaic Marker O, 2010

Images for the mosaic were collected on dive J2-540 on 10/31/10. The mosaic is roughly 

rectangular and covers an area of approximately 108.7 m2. Dead and living Lophelia pertusa cover 

the southwestern and northern portions of the mosaic. Areas not covered in Lophelia appear to be 

barren sea floor. Fourteen crabs, four anemones, and 24 crinoids are found around the Lophelia. 

Two Nettastomatidae eels are also observed in the north.

Figure 4-28. Photomosaic of Marker O in 2010 and digitization of this mosaic.
152

4.2.3.1.15 VK826: Mosaic Marker Q 

This site is located at 29.15873 ̊N 88.01053 ̊W at a depth of approximately 479 m. The mosaics 

are dominated by several clumps of living and dead L. pertusa.

4.2.3.1.15.1 VK826: Mosaic Marker Q, 2009 

Images for the mosaic were collected on dive J2-467 on 9/4/09. The mosaic encompasses a roughly 

rectangular area of about 48.5 m2. Live and dead Lophelia pertusa cover about 83% of this mosaic. 

Tubeworms are found in the western corner and near the center of the map. One encrusting sponge 

is also observed. Mobile fauna including one crinoid, three Nettastomatidae eels, two Hoplostethus 

occidentalis fish, one Moridae fish, eight sea stars, 59 crabs, one shrimp, and 18 urchins are also 

found at this site. Much of the mobile fauna is found around the center of the mosaic. 

Figure 4-29. Photomosaic of Marker Q in 2009 and digitization of this mosaic.

4.2.3.1.15.2 VK826: Mosaic Marker Q, 2010

Images for the mosaic were collected on dive J2-540 on 11/1/10. The mosaic encompasses a long 

rectangular area of about 78.3 m2. Live and dead Lophelia pertusa cover about 64% of the mosaic’s 

total area. Encrusting sponges are observed near the middle of the mosaic. Mobile fauna including 

three Hoplostethus occidentalis fish, one Laemonema goodebeanorum fish, 24 crabs, and six 

urchins are also found at this site. Much of the mobile fauna is found around the center of the 

mosaic near the living Lophelia.
153

Figure 4-30. Photomosaic of Marker Q in 2010 and digitization of this mosaic.

4.2.3.1.16 GB535: Mosaic Marker C

This site is located at 27.42798 ̊N 93.58346 ̊W at a depth of about 516 m. The mosaic is centered 

on three carbonate rock outcroppings with some sediment and mud between and around them. 

Some areas of the rock and sediment are covered in mussel shells. Sponges and whip corals are 

abundant in this mosaic, L. pertusa, Paramuricea sp. and Antipathes sp. are also present.

4.2.3.1.16.1 GB535: Mosaic Marker C, 2009

Images for the mosaic were collected on dive J2-460 on 8/28/09.The mosaic encompasses an area 

of approximately 39.2 m2. The dominant fauna at this location are whip corals, of which 197 are 

observed. Some living and dead Lophelia pertusa colonies are seen on the northernmost 

outcropping. Fifteen Paramuricea sp. and 27 Antipathes sp. can also be seen across the site. A 

number of mobile fauna were also observed. Five fish including two Moridae, two Hyperoglyphe 

perciformis, and one Hoplostethus occidentalis are present along with 25 crabs and 71 crinoids.
154

Figure 4-31. Photomosaic of Marker C in 2009 and digitization of this mosaic.

4.2.3.1.16.2 GB535: Mosaic Marker C, 2010

Images for the mosaic were collected on dive J2-531 on 10/20/10. The mosaic encompasses an 

area of about 40 m2. Sponges are found across the mosaic on the outcroppings along with 65 whip 

corals. A colony of Lophelia pertusa with some dead regions is seen on the northernmost 

outcropping. Mobile fauna at this site include three crabs, one unidentified fish, and 39 crinoids.

Figure 4-32. Photomosaic of Marker C in 2010 and digitization of this mosaic.
155

4.2.3.1.17 GB535: Mosaic Marker E 

This site is located at 27.42714 ̊N 93.58539 ̊W at a depth of approximately 520 m. The site is 

covered almost entirely in dead Lophelia pertusa with small areas of live L. pertusa. Callorgia sp. 

and whip corals are also abundant at the site.

4.2.3.1.17.1 GB535: Mosaic Marker E, 2009

Images for the mosaic were collected on dive J2-460 on 8/28/09. The mosaic encompasses a 

roughly square area of about 8.6 m2. Twenty-two Callogorgia sp. are concentrated across the 

northern half of the mosaic. Forty three whip coral, one Muriceides sp. coral colony, and one 

Antipathes sp. coral colony are also observed along with 93 small areas of living Lophelia pertusa

interspersed among the dead coral regions. Encrusting sponges, one tube worm, two anemones, 

six crabs, two urchins and 94 crinoids are also seen. 

Figure 4-33. Photomosaic of Marker E in 2009 and digitization of this mosaic.

4.2.3.1.17.2 GB535: Mosaic Marker E, 2010 

Images for the mosaic were collected on dive J2-531 on 10/21/10. The mosaic encompasses a 

roughly square area of about 19.3 m2. Antipathes sp., are found around the center of the mosaic. 

Twenty-four whip coral, and some encrusting sponges are also observed at this site. Twenty-eight 

mussels, 68 crinoids, one Hoplostethus occidentalis fish, four crabs, and one anemone are also 

found here. 
156

Figure 4-34. Photomosaic of Marker E in 2010 and digitization of this mosaic.

4.2.3.1.18 GC354: Mosaic Marker V, 2010 (only)

This site is located at 91.82641 ̊N 91.82641 ̊W at a depth of about 526 m. Images for the mosaic 

were collected on dive J2-529 on 10/19/10. The mosaic covers an area of approximately 21 m2. 

The mosaic features a raised carbonate rock outcropping in the center of the image. Dead Lophelia

pertusa coral extends from this rock to the north and east with a few interspersed areas of living 

Lophelia. Three sponges, 27 anemones, 36 crabs, and one Hoplostethus occidentalis fish are found 

at this site concentrated on and around dead Lophelia on the northern half of the site.
157

Figure 4-35. Photomosaic of Marker V in 2010 and digitization of this mosaic.

4.2.3.1.19 MC885: Mosaic Marker U, 2010 (only)

This site is located at 28.47330 ̊N 89.71707 ̊W at a depth of about 633 m. Images for the mosaic 

were collected on dive J2-527 on 10/16/10. The mosaic covers an area of approximately 26.4 m2. 

Most of the surface is mud but a few exposed carbonate rocks are visible with attached corals. Live 

and dead Madrepora sp. are observed on the central outcroppings. A number of Callogorgia sp. 

colonies can be seen on the seabed and other rocks. Eight ophiuroids are found on these 

Callogorgia sp. One isopod, one Moridae fish, and two urchins compose the rest of the visible 

mobile fauna. 

Figure 4-36. Photomosaic of Marker U in 2010 and digitization of this mosaic.
158

4.2.3.1.20 AT047: Mosaic Marker A, 2009 (only) 

This site is located at 27.88028 ̊N 89.78869 ̊W at a depth of approximately 834 m. Images for the 

mosaic were collected on dive J2-457 on 8/24/09. The mosaic encompasses a roughly square area 

of about 39.5 m2. The southern half and part of the northwest portions of the mosaic are covered 

in dead Madrepora sp. and the center of the northern mass features some living Madrepora sp. 

The rest of the mosaic is covered in sediment littered with clam shells and coral rubble with a few 

small outcroppings of carbonate rock. Paramuricea sp. is observed on the eastern and western 

corners covered in 21 ophiuroids. Thirty crabs, one sea star, five urchins, one pycnogonida, six 

shrimp, three whelks, and an anemone are also found at this site with the crabs concentrated on 

and around the patches of dead Madrepora sp.

Figure 4-37. Photomosaic of Marker A in 2009 and digitization of this mosaic.

4.2.3.1.21 MC118: Mosaic Markers T1 and T2, 2010 (only)

This site is located at 28.85275 ̊N 88.49270 ̊W at a depth of about 884 m. Images for the mosaic 

were collected on dive J2-538 on 10/30/10. The mosaic covers an area of approximately 25.5 m2. 

The primary substrate is mud with some dead coral. A carbonate rock outcropping is visible in the 

southwest corner. The sole coral found in this mosaic is the deep sea scleractinian Madrepora 

oculata. Living colonies are found at the center of the map growing on and surrounded by dead 

coral. Eighteen red crabs, Chaceon quinquedens, are visible among the coral. 
159

Figure 4-38. Photomosaic of Markers T1/T2 in 2010 and digitization of this mosaic.

4.2.3.1.22 MC118: Mosaic Marker X, 2010 (only)

This site is located at 28.85271 ̊N 88.49253 ̊W at a depth of about 883 m. Images for the mosaic 

were collected on dive J2-538 on 10/30/10. The mosaic covers an area of approximately 50.2 m2. 

The primary substrate is mud with some dead coral. Some carbonate rock outcropping is visible 

in the northeast corner and near the center. The sole coral found in this mosaic is the deep sea 

scleractinian Madrepora oculata. Living colonies are found along the center of the map growing 

on and surrounded by dead coral. Twenty-two red crabs, Chaceon quinquedens, and six as yet 

unidentified crabs are visible among the coral. One hundred fifty-two mussels are also present, 

concentrated mainly at the south corner of the mosaic but with smaller patches found along the 

center of the mosaic’s length.

Figure 4-39. Photomosaic of Marker X in 2010 and digitization of this mosaic.
160

4.2.3.1.23 MC294/338: Mosaic Marker AA, 2010 (only)

This site is located at 28.67224 ̊N 88.47652 ̊W at a depth of about 1,371 m. Images for the mosaic 

were collected on dive J2-541 on 11/3/10. The mosaic covers a large area of approximately 307.3 

m2. A rocky outcropping lies at the center of this mosaic with a shallow trough running down its 

center northwest to southeast dividing it in two. Paramuricea sp. is the most abundant coral at this 

site, of which there are 45 observed colonies. Thirty-nine ophiuroids are found on the 

Paramuricea sp. Three single colonies of Paragorgia sp., Clavaluria rudis, and Acanthogorgia 

aspera are also observed. Mobile fauna at this site include six anemones, 20 crabs, and one 

Nettastomatidae eel. The vast majority of fauna lies on the outcroppings. 

Figure 4-40. Photomosaic of Marker AA in 2010 and with each coral located on the mosaic.

4.2.3.1.24 GC852: Mosaic Marker 5, 2009 (only) 

This site is located at 27.10978 ̊N 91.16614 ̊W at a depth of about 1,400 m. Images for the mosaic 

were collected on dive J2-461 on 8/29/09. The mosaic covers a rectangular area of approximately 

38.7 m2. This mosaic is centered on a rocky outcropping populated by a diversity of corals 

including Leiopathes sp., Antipathes sp., Paramuricea sp., Madrepora sp., Isididae, and the 

encrusting octocoral Clavaluria rudis. Some small crabs are found on and around the coral and 

five ophiuroids are observed on a Paramuricea in the southeastern corner of the mosaic. Three 

anemones and one Moridae fish are also found in this mosaic.
161

Figure 4-41. Photomosaic of Marker 5 in 2009 and digitization of this mosaic.

4.2.3.2 Mosaics Imaged from a Vertical Perspective:

4.2.3.2.1 Vertical Mosaic F - J2-460 - GB535 - Heading 309 ̊ (8/28/09)

This site is located at 27.4273 ̊N 93.5852 ̊W at a depth of approximately 520 m. The mosaic is a 

profile of a carbonate rock outcropping (approximately 1.5 m height) with several colonies of 

Lophelia pertusa, occupying the uppermost portions of the outcrop and a smaller one near the 

base. Three whip corals are around the base, and about 15 crinoids are scattered across the mound. 

Eight Galatheid sp. are present, mainly on the live Lophelia pertusa colonies. A solitary anemone, 

Callogorgia sp., and Paramuricea sp., are also present.
162

Figure 4-42. Vertical Mosaic F.- J2-460 - GB535 - Heading 309 ̊ (8/28/09).

4.2.3.2.2 Vertical Mosaic 39 - J2-532 - GC140 - Heading 272 ̊ (10/22/10)

This site is located at 27.81112 ̊N 91.5372 ̊W at a depth of approximately 270 m. The mosaic is a 

profile of carbonate boulders; the uppermost boulder is densely populated with large Leiopathes

sp., with several Callogorgis sp. lower on the boulder. The lower portion of the boulder is covered 

in encrusting sponges, with whip corals flanking the boulder.
163

Figure 4-43. Vertical Mosaic 39.

4.2.3.2.3 Vertical Mosaic T1-T2 - J2-538 – MC118 - Heading 108 ̊ (10/30/10)

This site is located at 28.8527 ̊N 88.4927 ̊W at a depth of approximately 885 m. This mosaic is a 

profile of a low-elevation carbonate outcropping dominated by live Madrepora oculata growing 

on dead coral rubble. There are eight Chaceon quinquedens scattered about the Madrepora reef. 

There is one shrimp and Galatheid sp. crab in the middle of the image. There are no other coral 

species present.
164

Figure 4-44. Vertical Mosaic T1-T2.

4.2.3.2.4 Vertical Mosaic X - J2-538 - MC118 – Heading 34 ̊ (10/28/10)

This site is located at 28.8527 ̊N and 88.49257 ̊W at a depth of approximately 880 m. Mosaic X 

is dominated by live Madrepora oculata, with some dead coral rubble scattered around the base.

There is a solitary white sea urchin at the top of a Madrepora colony. There are approximately 10 

Chanceon quinquedens swarming the reef.

Figure 4-45. Vertical Mosaic X.
165

4.2.3.3 Comparison among Sites

To compare among sites, only one mosaic from each site was used in the analyses. The 2010 

mosaic was used if the site was mosaicked in both years, but if it was only imaged in 2009, then 

the mosaic from that year was used. The mosaics can be compared in three ways using Bray-Curtis 

dissimilarity values, and the figures shown here each reflect one of these comparisons: 1) One can 

compare the “substrata” (dominated by living and dead corals) present in each by comparing the 

relative polygon areas, where the relative area reflects the proportion of total polygon area 

occupied by each substratum type. This approach compensates for different total areas mosaicked. 

2) The solitary fauna (usually dominated by mobile fauna) can be compared between mosaics 

using the density of each faunal type, which again compensates for the different total sizes of the 

mosaics. 3) To compare the communities as a whole, the presence/absence of each type of fauna 

is compared. This is more sensitive to the size of the mosaics because none are capturing near the 

total diversity for the sites or regions: the larger the mosaic, the more of the total diversity likely 

to be sampled. This is one reason for the significant variation among mosaics and clearly indicates 

a high level of beta diversity within and among sites. 

The two GB535 mosaics and the three mosaics from MC751 were the only ones greater than 

80% similar to each other, and in some cases, mosaics from one site were less than 60% similar 

based on Bray-Curtis dissimilarity values calculated from species presence/absence (Figure 

4-46). In Figure 4-47, the similarities in substrate types within a site/area are evidenced by the 

high level of similarity among most of the VK906 and VK826 sites and the generally tight 

grouping between pairs of mosaics within a site. On the other hand, the high ß diversity between 

mosaics within sites like VK862 and overall within a region are also evident in this figure. 

Similarities among areas within a site and also the high level of ß diversity within sites and 

among regions are also evident in the solitary fauna (Figure 4-48). The role of different corals in 

influencing the structure of the different communities can be seen quite clearly when the same 

data is coded by the dominant coral found within the mosaic (Figure 4-49).
166

Figure 4-46. Hierarchical cluster dendrogram based on Bray-Curtis Index values of 

total faunal presence/absence showing the relationship between mosaic sites. If 

the site was imaged twice (in both 2009 and 2010), only the 2010 mosaic was 

used in this analysis. The mosaic sites are color-coded by lease block region.

Figure 4-47. Hierarchical cluster dendrogram based on Bray-Curtis Index values of relative 

polygon coverage showing the relationship between mosaic sites. If the site was 

imaged twice (in both 2009 and 2010), only the 2010 mosaic was used in this analysis. 

The mosaic sites are color-coded by lease block region.
167

Figure 4-48. Hierarchical cluster dendrogram based on Bray-Curtis Index values of 

solitary fauna density showing the relationship between mosaic sites. The 

mosaic sites are color-coded by lease block region.

Figure 4-49. Hierarchical cluster dendrogram based on Bray-Curtis Index values of solitary 

fauna density showing the relationship between mosaic sites. If the site was 

imaged twice (in both 2009 and 2010), only the 2010 mosaic was used in this 

analysis. The mosaic sites are color-coded by the dominant coral present at that 

mosaic site. 
168

When the same data is viewed in a multidimensional scaling ordination further insights into the 

patterns of solitary fauna biogeography become evident. Figure 4-50 shows the mosaics coded by 

region, and although there is some grouping by site, no clear discrimination by site is evident. In 

Figure 4-51, the mosaics are coded by dominant coral (data from Figure 4-49), and there is clear 

grouping of the communities associated with L. pertusa, and some evidence of grouping for other 

dominant corals. When the mosaics are coded by depth, the reason that some non- L. pertusa

communities grouped with the L. pertusa communities is evident, as is the primary role of depth 

as a determinant of community structure (Figure 4-52). The same factors and the primary role of 

depth are evident in analysis of the fauna coded as polygons (“substrata”) (Figure 4-53) and all 

fauna are analyzed as taxon presence/absence (Figure 4-54 with mosaics coded by depth).

Figure 4-50. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of solitary fauna density. Each point represents a mosaic site color-coded by 

lease block region. If the site was imaged twice (in both 2009 and 2010), only the 

2010 mosaic was used in this analysis.
169

Figure 4-51. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of solitary fauna density. Each point represents a mosaic site color-coded by the 

dominant coral present at that mosaic site. If the site was imaged twice (in both 2009 

and 2010), only the 2010 mosaic was used in this analysis.

Figure 4-52. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of solitary fauna density. Each point represents a mosaic site color-coded hotto 

cold by depth and labeled with the site depth in meters. If the site was imaged twice 

(in both 2009 and 2010), only the 2010 mosaic was used in this analysis.
170

Figure 4-53. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of relative polygon coverage. Each point represents a mosaic site color-coded 

hot to cold by depth and labeled with the site depth in meters. If the site was imaged 

twice (in both 2009 and 2010), only the 2010 mosaic was used in this analysis.

Figure 4-54. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of faunal presence/absence. Each point represents a mosaic site color-coded hot 

to cold by depth and labeled with the site depth in meters. If the site was imaged twice 

(in both 2009 and 2010), only the 2010 mosaic was used in this analysis.
171

Further insights into the role of region in the structure of the communities can be seen if much of 

the variation caused by depth and dominant coral is removed, and only the communities in the 

depth range where natural L. pertusa reefs are known to occur are included. Ordinations of both 

solitary fauna density and taxon presence/absence over this range clearly show mosaics grouping 

by site (Figure 4-55 and Figure 4-56). In these figures, the colors indicate the relative longitude 

with east to west going from hot to cold colors, and the communities seem to segregate by east and 

west of the Mississippi outflow as well (the Mississippi Canyon region being the dividing point).

Figure 4-55. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of solitary fauna density. Each point represents a mosaic site within the range 

of Lophelia pertusa (200-600 m) labeled by mosaic site. The points are color coded 

longitudinally east to west by a red to blue gradient. Mississippi Canyon locations are 

colored black with sites west of the Mississippi Canyon colored blue and those east 

colored red. The shapes of the points are grouped by lease block region. If the site was 

imaged twice (in both 2009 and 2010), only the 2010 mosaic was used in this analysis.
172

Figure 4-56. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of faunal presence absence of mosaic sites within the depth range of Lophelia

pertusa (200-600 m) labeled by mosaic site. The points are color coded longitudinally 

east to west by a red-to-blue gradient. Mississippi Canyon locations are colored black 

with sites west of the Mississippi Canyon colored blue and those east colored red. The 

shapes of the points are grouped by lease block region. If the site was imaged twice (in 

both 2009 and 2010), only the 2010 mosaic was used in this analysis.

4.2.3.4 Fidelity of Solitary and Mobile Fauna to Substratum Types

By comparing the distribution of the solitary fauna across substrata to the availability of these 

substrata, one can determine if particular species are found on specific substrata more often than 

would be expected by chance alone and therefore detect preferences of the solitary fauna for 

particular substrata or conditions (Podowski et al., 2010). The results of this comparison are 

presented in Figure 4-57 to Figure 4-61 for those species that were observed at least 10 times in 

the 2010 mosaics. In extreme cases, this analysis can provide strong evidence for the fidelity of 

particular solitary species for particular corals. This was apparent with ophiuroids showing a 

preference for gorgonian corals at most sites, (gorgonians are included in the “other biological 

substrata” in the figures) (Figure 4-57). . Sites are arranged from west to east. χ2 analyses tested 

the null hypothesis that fauna are randomly distributed across all substratum types (*p < 0.05, **p 

< 0.01, ***p < 0.0001).

The “other biological substrata” category include several different species, which very likely 

explains the different pattern seen at GC140 W for ophiuroids. The deep sea golden crab Chaceon

sp. was only seen at three sites and was only abundant when Madropora sp. was present (Figure 

4-57). Crinoids, on the other hand, while sometimes showing a preference for dead L. pertusa

(sites VK826 M and VK826 O for example), more often show a distribution mimicking that of 

available substrata (Figure 4-57). 
173

Two morphotypes of urchins were identified separately for this analysis and have similar 

distribution on available substrata. Statistical comparison is hampered by the low numbers of the 

Cidaris sp urchin; however, the absence of the other morphotype at all three MC751 sites where 

it occurs is notable and may reflect the integration of corals and tube worms at this site (Figure 

4-58). Both were sometimes present at the same site and were often found on living or dead 

scleractinian coral when it was present. 

The only colonial cnidarian treated in the solitary fauna class (as a point rather than a polygon) 

were the whip corals. They were only present on the western most sites. There is no evidence that 

these colonial corals have a substratum preference, although their presence on dead L. pertusa is 

notable (Figure 4-58). Two of the morphotypes of anemones (Actinia sp. and Actinoscyphia cf. 

saginata) have very similar distributions among sites, with both species present whenever either 

is abundant (Figure 4-59). Both are only rarely found on living biological substratum. The third 

morphotype is a type that burrows in sediment and as expected was never found on biological 

substrates and often present at sites without the other two morphotypes (Figure 4-59). 

In many cases, the total number of individuals at a site is simply too small to draw conclusions 

about distribution patterns (Figure 4-60). Low numbers of observations were typical for several 

taxa of the most mobile fauna, and patterns should emerge if this database is increased with future 

visits and additional sites. In one case, a morphospecies of galatheid crab, “crab type 5”, only 15 

individuals were seen, but all were found at a single site, MC294, which is both the most easterly 

of the mosaic sites and also the deepest. Another galatheid, Eumunida picta, was found at most of 

the sites visited, and although it is found more often on hard substrata in the areas mosaicked than 

the surrounding sedimented seafloor, there was no strong indication of a preference among the 

substratum types in the mosaics (Figure 4-61). The taxon category “individual sponges” is

polyphyletic. Close examination of this data set by sponge taxonomists might provide new 

information on distributions of different taxa, particularly at the two sites in MC751 (H1 and H2), 

where sponges were very often found associated with biological substrata other than scleractinian 

corals (Figure 4-61). 
174

Figure 4-57. The top three graphs show the percent of the total population of the taxon

(crabs, crinoids, brittle stars) that occurred on each substratum type at each 

site. Population size (n) at each site is shown over the columns. The bottom 

graph shows the percentage of each substratum type available at each site. 
175

Figure 4-58. The top three graphs show the percent of the total population of the taxon

(urchins, whip corals) that occurred on each substratum type at each site. 

Population size (n) at each site is shown over the columns. The bottom graph 

shows the percentage of each substratum type available at each site. 

0%

20%

40%

60%

80%

100%

GB535 C

GB535 E

GB299 B

GB299 D

GC354 V

GC140 W

MC751 G

MC751 H1MC751 H2

MC885 U

MC118 T1T2

MC118 X

VK906 J

VK906 L

VK906 Y

VK826 M

VK826 N

VK826 OVK826 Q

VK826 R

VK826 T

MC294 AA

0%

20%

40%

60%

80%

100%

GB535 C

GB535 E

GB299 B

GB299 D

GC354 V

GC140 W

MC751 G

MC751 H1MC751 H2

MC885 U

MC118 T1T2

MC118 X

VK906 J

VK906 L

VK906 Y

VK826 M

VK826 N

VK826 OVK826 Q

VK826 R

VK826 T

MC294 AA

0%

20%

40%

60%

80%

100%

GB535 C

GB535 E

GB299 B

GB299 D

GC354 V

GC140 W

MC751 G

MC751 H1MC751 H2

MC885 U

MC118 T1T2

MC118 X

VK906 J

VK906 L

VK906 Y

VK826 M

VK826 N

VK826 OVK826 Q

VK826 R

VK826 T

MC294 AA

0%

20%

40%

60%

80%

100%

GB535 C

GB535 E

GB299 B

GB299 D

GC354 V

GC140 W

MC751 G

MC751 H1MC751 H2

MC885 U

MC118 T1T2

MC118 X

VK906 J

VK906 L

VK906 Y

VK826 M

VK826 N

VK826 OVK826 Q

VK826 R

VK826 T

MC294 AA

Assessment Site

Percent Cover

Urchins (cf. Gracilechinus alexandri)

Available Substrata

Urchins (Cidaris sp.)

Whip Corals (Cirrhipathes)

65 24 4 1

8 8 4 9 8 10 6

Non-biol. Substrata

Other Biol. Substrata

Madrepora (Dead)

Madrepora (Live)

Lophelia (Dead)

Lophelia (Live)

3 1 1 9 1 1

Percent of Individuals per Substratum Type
176

Figure 4-59. The top three graphs show the percent of the total population of the taxon

(anemones) that occurred on each substratum type at each site. Population size (n) at 

each site is shown over the columns. The bottom graph shows the percentage of each 

substratum type available at each site. 

0%

20%

40%

60%

80%

100%

GB535 C

GB535 E

GB299 B

GB299 D

GC354 V

GC140 W

MC751 G

MC751 H1MC751 H2

MC885 U

MC118 T1T2

MC118 X

VK906 J

VK906 L

VK906 Y

VK826 M

VK826 N

VK826 OVK826 Q

VK826 R

VK826 T

MC294 AA

0%

20%

40%

60%

80%

100%

GB535 C

GB535 E

GB299 B

GB299 D

GC354 V

GC140 W

MC751 G

MC751 H1MC751 H2

MC885 U

MC118 T1T2

MC118 X

VK906 J

VK906 L

VK906 Y

VK826 M

VK826 N

VK826 OVK826 Q

VK826 R

VK826 T

MC294 AA

0%

20%

40%

60%

80%

100%

GB535 C

GB535 E

GB299 B

GB299 D

GC354 V

GC140 W

MC751 G

MC751 H1MC751 H2

MC885 U

MC118 T1T2

MC118 X

VK906 J

VK906 L

VK906 Y

VK826 M

VK826 N

VK826 OVK826 Q

VK826 R

VK826 T

MC294 AA

0%

20%

40%

60%

80%

100%

GB535 C

GB535 E

GB299 B

GB299 D

GC354 V

GC140 W

MC751 G

MC751 H1MC751 H2

MC885 U

MC118 T1T2

MC118 X

VK906 J

VK906 L

VK906 Y

VK826 M

VK826 N

VK826 OVK826 Q

VK826 R

VK826 T

MC294 AA

Assessment Site

Percent Cover

Anemones (cf. Actinia sp.)

Available Substrata

Anemones (Actinoscyphia cf. saginata)

Tube-dwelling Anemones (cf. Ceriantharia)

46 19 2

2 17 5 7 3 12 15 38 4 91 44 2

11 26 9 1 12 21 4 6 12 4 422 711 33

Non-biol. Substrata

Other Biol. Substrata

Madrepora (Dead)

Madrepora (Live)

Lophelia (Dead)

Lophelia (Live)

Percent of Individuals per Substratum Type
177

Figure 4-60. The top three graphs show the percent of the total population of the taxon

(crabs, fish) that occurred on each substratum type at each site. Population size 

(n) at each site is shown over the columns. The bottom graph shows the 

percentage of each substratum type available at each site. 

0%

20%

40%

60%

80%

100%

GB535 C

GB535 E

GB299 B

GB299 D

GC354 V

GC140 W

MC751 G

MC751 H1MC751 H2

MC885 U

MC118 T1T2

MC118 X

VK906 J

VK906 L

VK906 Y

VK826 M

VK826 N

VK826 OVK826 Q

VK826 R

VK826 T

MC294 AA

0%

20%

40%

60%

80%

100%

GB535 C

GB535 E

GB299 B

GB299 D

GC354 V

GC140 W

MC751 G

MC751 H1MC751 H2

MC885 U

MC118 T1T2

MC118 X

VK906 J

VK906 L

VK906 Y

VK826 M

VK826 N

VK826 OVK826 Q

VK826 R

VK826 T

MC294 AA

0%

20%

40%

60%

80%

100%

GB535 C

GB535 E

GB299 B

GB299 D

GC354 V

GC140 W

MC751 G

MC751 H1MC751 H2

MC885 U

MC118 T1T2

MC118 X

VK906 J

VK906 L

VK906 Y

VK826 M

VK826 N

VK826 OVK826 Q

VK826 R

VK826 T

MC294 AA

0%

20%

40%

60%

80%

100%

GB535 C

GB535 E

GB299 B

GB299 D

GC354 V

GC140 W

MC751 G

MC751 H1MC751 H2

MC885 U

MC118 T1T2

MC118 X

VK906 J

VK906 L

VK906 Y

VK826 M

VK826 N

VK826 OVK826 Q

VK826 R

VK826 T

MC294 AA

Assessment Site

Percent Cover

Crabs (Munidopsis sp.)

Available Substrata

Fish (Hyperoglyphe perciformis)

Fish (Hoplostethus occidentalis)

9 2 2

4 1 6 1

1

1

1 2 1 1 1 2 3

Percent of Individuals per Substratum Type

0%

20%

40%

60%

80%

100%

Non-biol. Substrata

Other Biol. Substrata

Madrepora (Dead)

Madrepora (Live)

Lophelia (Dead)

Lophelia (Live)

1
178

Figure 4-61. The top three graphs show the percent of the total population of the taxon

(crabs, sponges) that occurred on each substratum type at each site. Population 

size (n) at each site is shown over the columns. The bottom graph shows the 

percentage of each substratum type available at each site. 
179

4.2.3.5 Temporal Change in Communities between Years

Comparison of sites between years provides insights about both the coral community fauna and 

about the strengths and limitations of the technique. When the similarity between mosaics is 

compared based on presence absence of all species, all but three sites are more different between 

years than they are to other sites, and even those three pairs are less than 80% similar (Figure 4-62 

and Figure 4-63). This is clearly due to the solitary fauna (which includes the most mobile fauna) 

and not the fauna/biological substrata digitized as polygons (which is dominated by corals). When 

only the relative areas occupied by different categories digitized as polygons are compared, most 

pairs are quite similar between years (>80%), despite being digitized by different individuals in 

different years (Figure 4-64)). All mosaics were examined manually to determine if there were 

real changes in the corals between years. In most cases the differences appear to be do to 

differences in the altitude and lines between surveys (which leads to some distortion when the two 

are georeferenced to each other) and in some cases differences in digitization technique between 

years (and digitizers). In one case a loss of a L. pertusa colony was found to have been caused by 

ROV operations during deployment of a camera system. Another apparent difference was tracked 

to displacement of the marker by about 1 meter between visits. The biggest difference in the 

digitized polygon data set between years was found in the two mosaics from GB299, where the 

polygons are dominated by upright gorgonian corals, and relative size of polygons is highly 

dependent on the angles of the imaging (Figure 4-8 and Figure 4-9). Even these show over 65% 

Bray-Curtis similarity, and inspection of the original mosaics did not identify real changes in the 

populations or individuals. In no case was an unexplained significant difference in the corals 

supported by re-inspection of the mosaics. This suggests that despite the profound acute impacts 

of the Deepwater Horizon spill on coral communities in the vicinity of the Macondo well, the other 

communities surveyed as part of this study, including L. pertusa reefs 38 to 60 km to the North 

and 150 km to the west, were not acutely impacted by the spill in ways that were visually apparent 

four months after the well was capped.
180

Figure 4-62. Hierarchical cluster dendrogram based on Bray-Curtis Index values of total faunal

presence absence showing the relationship between the overlapping portions of mosaic 

sites imaged in both 2009 and 2010. The mosaic is color-coded by site and the shapes are 

grouped by lease block region. 

Figure 4-63. Non-metric multidimensional scaling ordination plot based on Bray-Curtis Index 

values of faunal presence absence showing the distance between the overlapping 

portions of mosaic sites imaged in both 2009 and 2010. Each point represents a mosaic 

color coded by site and grouped by shape according to lease block region. 
181

Figure 4-64. Hierarchical cluster dendrogram based on Bray-Curtis Index values of relative 

polygon coverage showing the relationship between the overlapping portions of 

mosaic sites imaged in both 2009 and 2010. The mosaics are color-coded by site and 

the shapes are grouped by lease block region. 

On the other hand, there were often very large and real differences between years with respect to 

solitary fauna. This faunal group is dominated by mobile fauna including crustaceans, fishes and 

echinoderms. Five of the sites showed less than 50% similarity (Figure 4-65). Although some of 

the differences between years are certainly a result of differences in resolution, different digitizers, 

and what fauna were visible during a survey (the 3-dimensional framework of the site allows plenty 

of places for fauna to hide from the camera), another component of the differences will be the fact 

that the mobile fauna are free to leave and return to the sites at will. Real variation in the presence 

of visible mobile fauna between years at the same sites was confirmed by re-inspection of the 

original mosaics. This suggests that a substantial amount of data will need to be acquired to 

accumulate the baseline information about this faunal group that will allow real changes to be 

detected over time.
182

Figure 4-65. Hierarchical cluster dendrogram based on Bray-Curtis Index values of solitary 

fauna density showing the relationship between the overlapping portions of mosaic 

sites imaged in both 2009 and 2010. The mosaics are color-coded by site and the 

shapes are grouped by lease block region.

4.2.4 Strengths and Weaknesses of Mosaics for the Study of Deep-sea Corals 

and Communities

Digitizing the mosaics for quantitative analyses is currently very time-intensive, and the benefits 

of using this approach must be weighed against the costs. There are clear advantages for general 

quantitative descriptions of the sites that allow evaluation of biogeographic patterns. Similarly, 

this approach is well suited to inventory both attached resident fauna and the mobile fauna that 

visit a site, and to investigate preferred substrata for mobile fauna and fidelity of fauna to particular 

geological and biological substrata. However, comparing the quantitative data from the digitized 

mosaics is of limited use for quantitative comparisons between years to detect small changes. This 

is because small differences in altitudes and the exact lines run during image collection will 

produce images with different two-dimensional projections of the three-dimensional corals. Also, 

artifacts are compounded when mosaics are digitized by different people, even with extensive 

cross-training and oversight.

However, the original mosaics can be used to detect change through manual re-inspection when 

the analysis of the quantitative data suggests it is warranted. Because the two years of mosaics 

bracketed the DWH incident, all mosaics were rechecked manually, and this provided hard data 

confirming a lack of acute effects of the incident on most of the known deepwater coral 

communities in the GoM.
183

This technique should provide considerable insight into in situ growth rates and patterns for the 

scleractinian corals imaged. However, the slow growth rates of deep sea scleractinians result in 

very small increments of growth over a single year, and this amount of growth is at the limit of 

detection for the images used in the down looking mosaics. The best imagery collected for this 

analysis was in 2010, and a repeat visit to some of these sites after 2013 will allow documentation 

of growth patterns and rates over this interval. As part of this study, four coral community 

monitoring stations were established with photographs taken from the side using a forward-looking 

camera (Figure 4-42 to Figure 4-45). These stations and precisely navigated horizontalperspective images of individual coral colonies will most likely prove to be more useful for growth 

studies in deep-sea corals.

The mosaic created for the site in MC338 was used in a very different way than the others. This 

site was found to have been impacted from the DWH incident (White et al., 2012). Analyses to 

determine the extent of the impact and ultimate fate of the impacted corals required that all corals 

at the site be identified and then followed as individuals over time (Appendix C-4 ). To accomplish 

this, the mosaic was used as a map (Figure 4-40). The map allowed us to plan and execute ROV 

dives to collect the images without impacting corals, to unambiguously identify specific individual 

coral colonies during each of 5 subsequent visits, and to unambiguously document the 

disappearance of a coral from the site between two of the visits. We have utilized this technique 

at several other sites investigated separately from this BOEM project, in the wake of the DWH 

incident.

4.3 INSIGHTS INTO COMMUNITY STRUCTURE, BIODIVERSITY AND BIOGEOGRAPHY 

FROM ANALYSES OF QUANTITATIVE COLLECTIONS

As part of the Lophelia II studies, quantitative sampling of coral, and a few mussel-bed 

communities was carried out in order to accomplish a number of the primary objectives of the 

larger project. At a first order, we set out to characterize newly discovered sites and examine 

patterns of community connectivity so the communities could be placed in the larger 

biogeographical context. Further, we set out to test whether natural and artificial substrates 

harbored distinct communities, and determine what were the specific factors governing community 

structure and diversity. 

4.3.1 Quantitative Collection Methods

Quantitative sampling of Lophelia communities, as well as any other appropriate communities 

encountered on natural or artificial substrates, was accomplished using the "mussel pot" collection 

devices. The coral pot samples will combine the advantages of quantitative sampling found with 

camera-guided grab samples with the precision and replication afforded by a submersible to 

provide the most comprehensive samples of specific habitat types while significantly minimizing 

our impact on the coral structures over the use of other sampling methodologies. These coral pot 

devices consist of a 'pot' made of 1/8" thick rolled aluminum. The interior diameter is 26 cm and 

the height of the pot is 29 cm. A Kevlar bag was attached to the pot and cinched closed by rotating 

a handle on the top of the pot connected to a draw string. 
184

On board ship, the coral pot collections were transferred to the cold room where large attached and 

unattached fauna were removed. The coral skeleton was rinsed and loose small fauna, sediment 

and other material was sorted through a series of sieves (1 mm, 250 μm, 63 μm), and material 

passing through a 1mm sieve but caught on the 250 μm and 63 μm sieve was preserved for 

meiofaunal analyses by Amanda Demopoulos (USGS). Associated macrofauna (>1 mm) were 

separated based on morphology and preliminary identifications were carried out. Prior to subsampling, associated fauna were identified to the lowest possible taxonomic level and enumerated. 

The average diameter, volume, and proportion of live coral were determined for the Lophelia

skeleton in each collection. Fragments containing live coral polyps were removed and sub-sampled 

for genetics for Cheryl Morrison (USGS). Sub-samples of foundation species and associated fauna 

were formalin-fixed and ethanol preserved (for morphological taxonomic studies and voucher 

collections), frozen (for stable isotope and molecular genetics studies), preserved in ethanol (for 

molecular systematic and phylogeographic analyses). See Chapter 6 for stable isotope studies and 

Chapter 5 for molecular genetics results. 

Diversity of associated fauna was assessed using a combination of statistics. Alpha diversity was 

estimated as species richness (number of species), using the Shannon-Weaver diversity statistic 

(an information content statistic measuring the apportioning of individuals among taxonomic 

units), and in rarefaction curves (number of new species per individual sampled at each site). Beta 

diversity was estimated as the similarity in community structure (presence and density of taxa) 

between pairs of samples using the Bray-Curtis statistic. Patterns in beta diversity were examined 

using cluster analysis to determine groupings of increasing numbers of samples based on the BrayCurtis statistic, and multidimensional scaling, a non-parametric ordination technique also based 

on the Bray-Curtis similarity metric. All analyses were carried out in Primer V 6.0.

4.3.2 Quantitative Collection Results and Discussion

There were 22 collections made at 12 different sites ranging in depth from 388 m to 2445 m (Table 

4-4). There were 17 collections of L. pertusa-associated communities, three of Bathymodiolus

mussel-associated communities, and two of Madrepora oculata communities. There were between 

1 and 183 individuals of associated fauna in each collection, and between 1 and 15 species in each 

collection (Table 4-5). In all collections together, there were 64 species; 50 species associated with 

L. pertusa, 8 species associated with M. oculata, and 17 species associated with Bathymodiolus

sp. Of the species associated with L. pertusa, 26 of these were collected in this study for the first 

time. This brings the total number of macrofauna species known to be associated with L. pertusa

to at least 90, although this number could be even higher considering that the taxonomy of some 

of these species remains unresolved. 
185

Table 4-4.

Collection information for all coral pot samples taken during this study 

Dive Date Site Latitude Longitude Depth Collection Foundation Species Name

(m) Device

J2-453 2009/08/21

WFla 

Slope 26°10.84 84°42.32 443 MP-D Lophelia pertusa Wfla

J2-454 2009/08/23 DC583 28°23.09 87°23.30 2445 MP-D Bathymodiolus sp. DC583

J2-457 2009/08/24 AT047 27°52.79 89°47.30 853 MP-D Bathymodiolus sp. AT047-1

J2-457 2009/08/24 AT047 27°52.81 89°47.33 839 MP-B Madrepora oculata AT047-2

J2-460 2009/08/28 GB535 27°25.68 93°35.03 515 MP-D Lophelia pertusa GB535-1

J2-460 2009/08/28 GB535 27°25.81 93°34.65 511 MP-F Lophelia pertusa GB535-2

J2-460 2009/08/28 GB535 27°25.64 93°35.13 515 MP-B Lophelia pertusa GB535-3

J2-464 2009/09/01 MC751 28°11.63 89°47.93 441 MP-B Lophelia pertusa MC751-1

J2-464 2009/09/01 MC751 28°11.63 89°47.90 439 MP-D Lophelia pertusa MC751-2

J2-465 2009/09/02 VK906 29°4.18 88°22.62 388 MP-F Lophelia pertusa VK906-1

J2-465 2009/09/02 VK906 29°4.16 88°22.65 393 MP-D Lophelia pertusa VK906-2

J2-466 2009/09/03 VK826 29°9.89 88°0.70 463 MP-B Lophelia pertusa VK826-8

J2-466 2009/09/03 VK826 29°9.46 88°0.97 475 MP-D Lophelia pertusa VK826-9

J2-467 2009/09/03 VK826 29°9.52 88°0.63 469 MP-F Lophelia pertusa VK826-10

J2-472 2009/09/10 Gulfpenn 28°26.47 89°19.09 557 MP-D Lophelia pertusa Gulfpenn

J2-473 2009/09/11 VK906 29°4.14 88°19.09 393 MP-D Lophelia pertusa VK906-3

J2-528 2010/10/17 GC246 27°42.10 91°38.91 834 MP-B Bathymodiolus sp. GC246

J2-529 2010/10/18 GC354 27°35.87 91°49.58 526 MP-B Lophelia pertusa GC354-4

J2-531 2010/10/20 GB535 27°25.68 93°35.01 518 MP-B Lophelia pertusa GB535-4

J2-536 2010/10/26 MC751 28°11.61 89°47.92 440 MP-B Lophelia pertusa MC751-3

J2-537 2010/10/27 Gulfoil 28°9.68 89°45.15 532 MP-B Lophelia pertusa Gulfoil

J2-538 2010/10/29 MC118 28°51.16 88°29.55 884 MP-B Madrepora oculata MC118
186

Table 4-5. 

Summary statistics from community collections 

.Name

Volume 

(mL)

avg diam 

(cm)

surface 

area Diversity

Live Dead Live dead (cm2) %live #sp #ind H' J' Es(10) Es(20)

Wfla 77 330 0.48 0.72 2472 18.9 8 13 1.93 0.926 6.8 8.0

DC583 - - - - - - 7 51 1.19 0.610 3.6 5.2

AT047-1 - - - - - - 7 127 1.24 0.639 3.7 5.0

AT047-2 - - - - - - 2 2 0.69 1.000 2.0 2.0

GB535-1 - 310 - 0.73 1701 0.0 3 3 1.10 1.000 3.0 3.0

GB535-2 - 240 - 0.71 1345 0.0 3 10 0.64 0.582 3.0 3.0

GB535-3 - 1490 - 0.91 6542 0.0 8 19 1.99 0.955 6.3 8.0

MC751-1 290 770 0.82 0.75 5552 27.4 8 17 1.69 0.814 5.6 8.0

MC751-2 5 110 0.70 0.68 677 4.3 2 4 0.56 0.811 2.0 2.0

VK906-1 165 1320 0.93 1.37 4564 11.1 10 43 1.74 0.754 4.9 7.0

VK906-2 40 300 1.15 1.10 1230 11.8 5 19 1.19 0.740 3.8 5.0

VK826-8 40 740 0.72 1.12 2865 5.1 7 14 1.73 0.889 5.8 7.0

VK826-9 - 470 - 0.78 2410 0.0 4 4 1.39 1.000 4.0 4.0

VK826-10 370 95 1.18 0.62 1870 79.6 1 1 0.00 - 1.0 1.0

Gulfpenn 260 342 0.78 0.91 2828 43.2 9 183 0.73 0.332 2.4 3.5

VK906-3 5 390 0.66 0.96 1664 1.3 3 4 1.04 0.946 3.0 3.0

GC246 - - - - - - 5 11 1.41 0.879 4.8 5.0

GC354-4 9 1586 0.31 0.80 8046 0.6 15 20 2.52 0.932 8.2 15.0

GB535-4 9 102 0.50 0.71 647 8.1 12 17 2.40 0.964 8.2 12.0

MC751-3 247 0.74 1335 0.0 4 4 1.39 1.000 4.0 4.0

Gulfoil 77 493 0.66 0.97 2500 13.5 4 30 0.43 0.314 2.0 3.0

MC118 - - - - - - 6 9 1.68 0.936 6.0 6.0

The most common species were polychaetes (Appendix C-1). These included Euratella sp., a tubedwelling, suspension-feeding sabellid worm; Glycera tesselata, a small predatory polychaete; and 

Eunice sp., the larger, tube-dwelling, predatory polychaete that was part of the laboratory timelapse study (Chapter 7). Following these species, were sessile epifaunal and encrusting species 

including unidentified species of small anemones and sponges. Other common mobile fauna 

included Coralliophila sp., the corallivorous gastropod, a few different species of Munidopsis, and 

unidentified species of amphipods. 

Diversity ranged from one species and a Shannon-Weaver H’ value of 0 in one of the collections 

from VK826 to 15 species in 20 individuals collected H’ = 2.52) in GC354-4. Diversity of all L. 

pertusa-associated communities collected to date (including those from Lophelia I, Cordes et al. 

2008) was most related to the surface area of coral in the collection (Figure 4-66). This was evident 

for both the total number of species (r2 = 0.583, p < 0.0001) and for the Shannon-Weaver diversity 

index (r2 = 0.241, p = 0.0044). In the Lophelia I study, the Bushmaster junior device was used for 

coral collections, while in this study, the mussel pot collection device was used. While the mussel 

pots had numerous advantages, including multiple collections per dive and smaller size on the 

ROV basket, the Bushmaster samples were more likely to provide a comprehensive survey of 

community composition. Secondarily, diversity was inversely related to the proportion of live 
187

coral in the collection in terms of Shannon-Weaver diversity (r2 = 0.171, p = 0.0188), but not 

number of species (r2 = 0.040, p = 0.2721), with dead coral framework supporting higher diversity 

levels. This pattern has been observed repeatedly in L. pertusa habitats in a variety of locations 

including the GoM (Cordes et al. 2008, Lessard-Pilon et al. 2010) and Norway (Mortensen et al. 

1995), and using a variety of sampling methods.

Figure 4-66. Diversity of coral communities collected during Lophelia I and II related to 

characteristics of the coral skeleton in the collections. Only significant regression 

relationships are shown. 

Diversity did not show any significant trends with either depth or longitude (east-west patterns). 

The lack of a trend with depth is likely to be a result of the narrow range of depths sampled (313 

to 557 m), with the majority of the collections were between 400 and 525 m due to the restricted 

range of L. pertusa on natural substrata in the Gulf. The lack of a trend in diversity from east to 

west is similar to the lack of a trend in the diversity of octocoral communities (see section 5.1).

This is also consistent with a lack of a trend in the diversity and community composition of seep 

communities (Cordes et al. 2007). 

When all communities were analyzed together, there was a very high level of beta diversity, with 

low similarities shown among large groups of collections. The two M. oculata community 

collections did not have any species in common. It is clear that the macrofaunal communities 

associated with this deep-living scleractinian species require further investigation. The 

Bathymodiolus sp. communities sampled in this study only shared one species in common, the 

chiton that was present at both AT047 and MC118. Species that were associated with L. pertusa

that also appeared in one or more of these collections include Glycera tesselata from the seep at 

GC246, Munidopsis sp. 1 in both mussel and coral habitats at AT047, and Phascolosoma turnerae

at GC246. All of these species are very common in the GoM and had previously been reported 

from both seep and coral habitats. Because of the low numbers of shared species among all 

foundation species, additional community analyses focused on the L. pertusa collections from this 

study supplemented with those from the Lophelia I study (Cordes et al. 2008; CSA, 2007). 

The ordination plot (Figure 4-67) reveals the high beta diversity (low overall community 

similarity) at the large, heterogeneous site of VK826, with lower levels of diversity at most of the 

other sites. The western sites of GB535, GC354, and GC234 appear to be clustered in the 

ordination, suggesting lower beta diversity and an overall similarity in community composition 

within those sites. However, the overall level of community similarity between the sites is fairly 

low, particularly between GB535 and the two Green Canyon sites. The MC751 and VK906 sites, 
188

although fairly small in extent, represent larger areas of the ordination, suggesting higher beta 

diversity within these sites than the western sites. Interestingly, the two wreck sites, Gulfpenn and 

Gulfoil were most similar to one another, with a Bray-Curtis similarity value of 35.5, driven by 

the high abundance of anemones in both collections. Depth and distance between collections did 

not appear to influence the patterns in community similarity, with collections from different sites 

at different depths clustering among one another, for example GB535-1 was most similar to 

VK906-2 and GC234-1 was most similar to VK826-1. The lack of an effect of depth in this data 

set likely represents the limited depth range of the collections, and of the known L. pertusa

distribution on natural reefs.

Figure 4-67. Multidimensional scaling ordination plot of community similarity (based on BrayCurtis similarity), where collections that appear closer together have higher 

community similarity. 

4.4 BIODIVERSITY AND FIDELITY OF CORAL ASSOCIATES

4.4.1 Introduction

Deep-sea corals provide habitat structure for an array of species that have developed diverse 

symbiotic relationships with relative specificities to their host corals (Watling et al. 2011). Corals 

provide complex structures that can host other organisms and their importance as biotic substrate 

increases with depth as the complexity of geological substrate declines (Buhl-Mortensen et al. 

2010). To date, 5 of the 32 known Phyla occur as symbionts on deep-water corals. These include 

Cnidaria, Annelida, Mollusca, Arthropoda (Crustacea) and Echinodermata. Several studies have 

shown specific relationships between corals and associated symbiont living on these corals and 

have alluded to the importance of understanding these relationships to understand the evolution of 

diversity in the deep ocean (Shank 2010). Diverse invertebrate fauna, from attached forms such 

as anemones and hydroids to mobile crustaceans, particularly anomuran and palaemonid shrimp, 
189

and ophiuroids are now known to exist as “associates” on deep-sea corals. However, very little is 

known about the ecological requirements of these interactions and strategies maintaining the 

relationships among hosts and associated epibiotic symbiont (Buhl-Mortensen and Mortensen 

2004a; Buhl-Mortensen and Mortensen 2004b). The few specific examples include the Atlantic 

shrimp Pandalus propinquus and Caridion gorgoni that are considered to be facultative 

commensals on the deep-sea corals Paragorgia arborea and Lophelia pertusa, and the shrimp 

Synalpheus townsendi reported to be a facultative commensal on Oculina reefs. In the Pacific 

Ocean, the shrimp Periclimenes franklini and P. propinquus are considered to be facultative 

symbionts of the cold-water corals in the Coral Sea. 

Mutualism is an interaction in which both individuals benefit from the interaction. Obligate 

mutualisms are those in which both partners require the presence of the other to survive and/or 

grow and/or reproduce. Facultative mutualisms are those in which the participating species can

survive/grow/reproduce without each other, but generally do better if the partner is present. For 

example, in the plant world, some aphids cannot survive unless they are tended by ants. Thus they 

have an obligate interaction with ants. However, the ants often do not require the aphids to survive. 

Their interaction with the aphids is considered facultative. For deepwater corals and their epibiotic 

symbionts, these two categories represent end points on a continuum. For example, interactions 

can also be specialized or generalized. Specialists are organisms that only interact with one or a 

few species. Generalists interact with many species. Thus obligate and specialized would be 

considered when an organism interacts with only one or a few species, and they must interact to 

survive, while facultative and specialized would be considered when an organism does not require 

the interaction, but if they do, it is with only one or a few other species. Historically, invertebrate 

symbionts of corals have been routinely classified as commensalistic, parasitic or mutualistic 

according to the relationship of the ‘guest’ to the ‘host’. This is typically categorized as +/0 for 

commensals, +/- for parasites and +/+ for mutualists, among the various relationships along the 

symbiotic continuum, the symbols indicating the effect of the association on the fitness of the guest 

and the host. In all cases, the fitness of the guest is enhanced by the association, but the fitness of 

the host may be unaffected, negatively impacted or improved (Watling et al., 2011).

Determining the types of relationships for deepwater corals and their associated fauna, is extremely 

difficult, and thus rarely done. The “fidelity” of these relationships is largely if not entirely 

unknown. Fidelity refers to not only the species composition of the specificity of the coral and 

associate relationship, but the strength of that relationship. In general, most deepwater coral 

symbionts live on a narrow range of host species. Multiple host species may be in the same 

geographical area, on the same seamount perhaps, but may not be closely related phylogenetically 

(Watling et al., 2012). One of the few examples of a well documented case of high host fidelity is 

the ophiuroid, Ophiocreas oedipus, who lives only on the chrysogorgiid coral, Metallogorgia 

melanotrichos, and somehow no other symbionts appear to be allowed to take up residence 

(Mosher and Watling, 2009). Indeed, among >200 observations from both the Atlantic and Pacific, 

no living M. melanotrichos has been observed without its O. oedipus symbiont or with more than 

one symbiont. However, examples like this are few.

During the present study, it was our first-tier goal to identify x coral and associated symbionts 

taxonomically, in order to identify the composition and distribution of coral-associate partnerships 

that exist in the deep GoM. Then, to utilize high-resolution imagery as possible to conduct 
190

sufficient observations of deepwater corals and their symbionts to detect patterns in the distribution 

of coral and associated symbiont composition that might shed light on both the symbiotic nature 

of the relationship (facultative vs. obligate) as well as host symbiont fidelity.

The GoM is considered to be part of the western Atlantic and Caribbean biogeographic area 

(Neigel 2009). It is divided into a northern area, which is part of the warm-temperate Carolinian 

Marine Province and a southern area that is part of the Tropical Northwestern Atlantic Province. 

There is a further subdivision of the northern GoM into a northeastern and a northwestern region 

separated by the mouth of the Mississippi River or Mobile Bay, AL. These two northern areas 

differ geologically and in physical conditions often reinforced by the outflow of the Mississippi 

and Atchafalaya rivers (Neigel 2009).

We examined more than fifteen stations with deep sea coral (DSC) communities in the deep GoM

and additional sites ranging from 5 to about 100 miles from the wellhead in the wake of the DWH

incident. In addition to assessing the composition of coral associates via taxonomy (see associate 

genetic section), we documented putative patterns of associative relationships between particular 

invertebrates and their host corals via high-resolution imaging and sampling of representative taxa. 

4.4.2 Methods

4.4.2.1 Coral Associate Sample Collection for Image Reference

Samples of DSCsand their invertebrate associates in the GoM were collected by the ROV SeaEye 

Falcon DR during the TDI-Brooks R/V Nancy Foster/SeaEye Falcon expedition (September 20 

to October 2, 2008), the ROV Jason II during the TDI-Brooks R/V Ron Brown/Jason II

expeditions (August 6 to September 12, 2009 and October 15 to November 1, 2010), and using an 

industrial ROV on board the R/V Holiday Chouest during a non-Lophelia II research expedition 

(October 1 – 24, 2011) (Figure 4-68). Collection depths were between 249 m and 2600 m. 

Figure 4-68. Lophelia II coral associate sampling sites in the GoM. GB = Garden Banks, GC = 

Green Canyon, MC = Mississippi Canyon, VK = Vioska Knoll, and DC = DeSoto 

Canyon.
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The biological samples were processed immediately after recovery of the ROV. For each sample, 

tissue was either frozen at -80°C or preserved in 70% ethanol for subsequent genetic analyses. 

Images of the colonies were taken during the collection; additional images were taken in the wet 

laboratory on board the ship. 

4.4.2.2 Analysis of Reference Sample Collections

We compiled and analyzed the collection records from the Lophelia II 2008, 2009, and 2010 

cruises to the GoM to study patterns of association and fidelity between coral hosts and their 

invertebrate associates. Collected samples of invertebrate associates were identified to the lowest 

taxonomic level possible and as discrete morphospecies and correlated to the coral hosts from 

which they were collected.

4.4.2.3 Lophelia II 2009 Video Analysis

We analyzed 178 hours of high-resolution video footage collected with the ROV Jason II during 

the cruise Lophelia II in 2009 in the GoM. The video was subsampled collecting discrete framegrabs of well-imaged (i.e., the identity of the coral and associate were observable in the image with 

reference to the collected samples) coral communities and their invertebrate associates. These 

images were then reviewed to quantify corals and invertebrate coral associates which were 

identified to the lowest taxonomic level possible.

4.4.2.4 Multivariate Analysis

To assess the compositional distribution of coral associates, image data subsampled from the 

Lophelia II 2009 cruise was standardized by total observations made in a sample bin. Relative 

abundances were used rather than abundances calculated from area because of the high degree of 

variability in the altitude of the ROV and in the magnification of the camera throughout the dives. 

Correlation matrices using the Bray-Curtis similarity index on fourth-root transformed data were 

generated and cluster analysis and multidimensional scaling (MDS) were used to determine 

similarity of biological assemblages based on species composition. In addition, an analysis of 

similarity (ANOSIM) was performed to test for differences between these biological assemblages. 

The analyses were performed at several scales by grouping the observations into different sample 

bins: 

1. By geographic region, examining regional differences between 

a. The northeastern GoM (east of the Mississippi River mouth)

b. The northwestern GoM (west of the Mississippi River mouth)

2. By 500 m depth bins, examining differences in community structure by depth

a. 0-500 m

b. 500-1000 m

c. 1000-1500 m

d. >1500 m

These analyses were performed with the statistical package PRIMER v6 (Clarke and Gorley 2006; 

Clarke and Warwick 2001) and the results presented below. 
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4.4.3 Results

4.4.3.1 Coral-Associate Composition and Distribution

More than 720 coral-associated invertebrate individuals (including species of brittle stars, shrimp, 

amphipods, anemones, barnacles, and crabs) were sampled for species and coral-relationship 

determination (Appendix C-1). 

A total of 123 coral colonies were imaged and analyzed from nine different sites in the GoM (Table 

4-6). Coral hosts are listed at left column and the associated invertebrate fauna are listed along the 

top row, by groups within phyla. Each letter represents a unique associate morphospecies within 

a particular phylum. The total number of morphospecies found either on a host coral or within an 

associate group is listed at right and bottom. We have identified more than a total of 120 

invertebrate morphospecies from 6 phyla living on >18 host coral substrates, including octocorals, 

black corals, and scleractinian corals from the 3 Lophelia II cruises between 2008-2010 (Figure

4-69, Table 4-6). Of these 120 morphospecies of coral associates, the most common and diverse 

associates were from the phyla Arthropoda (38 distinct morphospecies, dominated by

galatheid/chriostylid crabs) and Echinodermata (30 different morphospecies, primarily ophiuroid 

brittle stars). While species of crustaceans were the most diverse on corals, the most abundant 

taxa observed by site were anemones (Table 4-7; WFS = W. Fl. Slope, DC = DeSoto Canyon, AT 

= Atwater, GB = Garden Banks, GC = Green Canyon, MC = Mississippi Canyon, VK = Vioska 

Knoll.). Coral-associated species hosted only by dead coral skeleton (e.g., specific barnacles and 

polychaetes) were also observed. The corals with the greatest diversity of associates were the live 

scleractinian Lophelia pertusa and the paramuriceid species. At least 7 species of sponges 

(previously not identified as being important or abundant associates living on deep-water corals, 

Watling et al. 2012) were observed on L. pertusa. Interestingly, sponges and polychaetes were not 

observed on any other live host coral taxa (Table 4-6). Aploacophorans (along with gastropods) 

are the one of the few known molluscan groups considered as coral associated symbionts. This 

was also observed to be true in our sample collection, with 4 aplacophoran species living 

commensally on Muriceides, a plexaurid, and paramuriceid corals. . While Crustaceans are the 

most speciose among Gulf coral associates, the most abundant associates on Gulf corals are 

anemones and ophiuroids (Table 4-7).
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Table 4-6.

Composition and distribution of coral associated symbionts by coral host type. 

PHYLUM: ANNELIDA ARTHROPODA CNIDARIA ECHINODERMATA MOLLUSCA PORIFERA Total

Polychaeta Crustacea Anemones Hydroids Zoanthids Ophiuroidea Aplacophora Gastropoda Sponges Species

Alcyonacea

Bamboo coral D D 2

Callogorgia T F, G A, C, D, F, K, L, M B, C, E 13

Chrysogorgia E, M 2

Corallium F B 2

Keratoisis D, J, P, S, X D, L 7

Muriceides? C B D A 4

Nicella white A C 2

Paragorgia C, G 2

Paramuriceid A, G, I, L B, H B B, C B,C, D, G, M A, B B 17

Plexaurid A 1

Primnoid C, K 2

Purple 

gorgonian C, G 2

Antipatharia

Antipatharian G, I, J, L, AA H, I, N 8

Dead 

Antipatharian A H C 3

Leiopathes G, I, J, K, M, AA C, F B C E 11

Tanacetipathes D, O, Q B 4

Scleractinia

Dead Lophelia B, C, E A J 5

Lophelia D, F, G, H, I B, D, O, R, U, V, 

W, Y, Z A, C, E B A, F D, O A, B, C, D, A, B, C, D, E, F, G 33

Total Species 9 38 11 7 6 30 4 8 7 120
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Figure 4-69. Coral associate taxonomic composition by phyla over three Lophelia II cruises.

Table 4-7.

Abundance of coral associates across five different phyla observed in a subset of coral colonies 

imaged during the 2009 cruise. 

Site Coral Colonies Cnidarians Echinoderms Porifera Crustaceans Annelids

WFS 16 178 11 54 3 0

DC583 20 147 18 0 0 0

AT047 9 57 36 0 0 0

GB299 17 498 210 1 1 0

GB535 16 564 39 36 5 0

GC852 21 374 13 1 1 0

GC338 1 25 1 0 1 0

MC751 15 238 152 1 5 15

VK826 8 139 3 0 0 0

Total 123 2220 483 96 16 15
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4.4.3.2 Multivariate Analysis

Similarities between the associated faunal communities on coral colonies were determined using 

multivariate statistical analyses. Cluster analysis and MDS indicate that there is a distinct 

difference between the coral colony associates found in the northeastern GoM and those found in 

the northwestern GoM, which was found to be highly significant by ANOSIM analyses (p=0.001) 

(Figure 4-70). When observations were binned across the GoM into 500 m depth bins, cluster 

analysis and MDS indicated distinct differences between different depth regions, which were 

found to be highly significant by ANOSIM analyses (p=0.001) (Figure 4-71).

Figure 4-70. Multidimensional scaling plot of coral associates located in the northeastern 

GoM (East, green triangles) and the northwestern GoM (West, blue triangles) 

using the Bray-Curtis similarity index. The distinction of east and west is 

delineated by the location of the entrance of the Mississippi River into the Gulf. 

Ordination points superimposed by geographic area.
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Figure 4-71. Multidimensional scaling plot of coral associates for 500 m depth bins using the 

Bray-Curtis similarity index. Ordination points superimposed by depth region: Green 

= 0-500 m, Cyan = 500-1,000 m, Red = 1000-1500 m, Blue > 1,500 m.

4.4.3.2.1 Assessing associates as indicators of coral ecosystem health

The Lophelia II program provided critical observations and baselines that enabled an unintended 

outcome of comparative studies of a coral community located approximately 11 km southwest of 

the DWH oil spillat a depth of 1370 m. This site was observed over the course of 5 ROV and 

submersible Alvin dives from November to December 2010 in conjunction with Lophelia II 

expeditions. The ophiuroid associates of 52 corals within this impacted community were imaged 

over the course of 5 five ROV and submersible Alvin dives from November to December 2010. 

The time series of images were analyzed for changes in color, movement, and posture, (White et 

al., 2012).

Of the 52 coral hosts examined at the coral community at MC294, 2% hosted actinarian anemones, 

73% hosted the ophiuroids Asteroschema clavigerum, and 25% had no associates. A. clavigerum

is normally tan to red in color (Figure 4-72), but 44% had distinctly white arms and 9% were 

almost entirely bleached. A. clavigerum typically have arms tightly-coiled around their coral hosts, 

but 27% had abnormal posturing with loosely coiled arms. Between two visits to the site 

approximately one month apart, 13% of ophiuroids transitioned from the tighly-coiled to loosely 

coiled posture and two individuals sent a completely splayed-out posture with their arms hardly 

coiled around the corals, a previously undocumented behavior (Figure 4-72) (White et al. 2012).
197

Figure 4-73. Images of Asteroschema clavigerum from MC294. The top two images show the 

typical tan to red coloration and tightly-coiled arm posture observed in this species. 

The bottom two images show the white armed and completely bleached coloration as 

well.

4.4.4 Discussion

4.4.4.1 Taxonomic Composition and Associations

The most abundant phyla of invertebrate associates of corals observed in this study were the 

Arthropoda (mainly crustaceans), the Echinodermata (mainly ophiuroids), and the Cnidaria 

(hydroids and anemones). The crustacea are often abundant where benthic biomass is often 

dominated by suspension feeders that provide important habitat for smaller invertebrates (Metaxas 

and Davis 2005; Rogers 1994; Samadi et al. 2007; Stocks 2004). The patterns of associate fidelity 

to coral hosts correspond with previous studies of corals and their associates. The reef-forming 

scleractinian Lophelia pertusa hosted the largest number of morphospecies of associates based on 

the 2008-2010 cruise observations, perhaps owing to the frequent mixture of living and dead L. 
198

pertusa material and the specific fauna associated with both types of material. Comparison of the 

associates found on dead L. pertusa to those on live L. pertusa associates found 5 distinct species, 

including polychaetes, barnacles, hydroids, and ophiuroids that were observed only on dead L. 

pertusa. In addition, the observation of associates with higher fidelity occurring on gorgonians is 

similar to previous studies that found facultative and highly specialized relationships between 

corals and associated fauna (Buhl-Mortensen and Mortensen 2004a; Buhl-Mortensen and 

Mortensen 2004b; Buhl-Mortensen and Mortensen 2005; Buhl-Mortensen et al. 2010).

Associative relationships were identified from video and sampling to yield more than 110 coralassociate partnerships. When we observed a particular associate living on any coral on 20 or more 

occurrences, we regarded this as a association pair candidate. If an association with a single 

species of coral occurred 100% of these observations, we considered this to be an association of 

“obligate” mutualism. Any percentage less than 100%, would place the candidate association in 

a “facultative” category. We noted few findings of having “obligate” associations by this 

definition, in fact there were only a few (e.g., Asterschema clavigerum on Paramuricea biscaya), 

with more with multiple host corals –for example, the shrimp Bathypalaemonella serratipalma

observed only on Chrysogorgia spp. and Iridogorgia spp. (a similar relationship was observed in 

deep-sea coral communities on the New England and Corner Rise Seamounts, Cho 2008). We 

noted that if we were to lower the required percentage to 80% (from “obligate” to “high fidelity) 

or allow for multiple hosts (“obligate general”), many taxa, particularly almost all ophiuroid 

species (e.g., Asteroschema spp and Astrogomphus sp.) and crab species (chriostylid and galatheid 

spp.) immediately fall into this category. Assigning any of these to obligate, facultative, 

mutualistic or even fidelity in many cases, would require greater observations and sampling to be 

certain of associate taxonomic identity. While we note that many (120 morphospecies of 

associates) of coral-symbiont associations exist in the Gulf (the extent of which was clearly not 

known prior to this study) with the observation that similar patterns exist in the Atlantic (Shank 

2010), the work to appropriately designate and assess the fidelity of host and associate corals is 

ongoing. 

4.4.4.2 Regional Patterns

In the comparison of coral associates within the study area, the coral associate communities 

of the northeastern and northwestern GoM were found to be significantly different. This regional 

difference was observed in the multivariate analyses of coral associate community composition 

performed on the regional scale. A similar pattern of regional differences was observed in 

megafauna assemblages associated with deep-water gorgonian corals in different sites in the 

Northeast Channel in Canada (Metaxas and Davis 2005). 

These regional differences may be caused by a variety of factors (Neigel 2009). 

Geologically, the northwestern GoM is characterized by terrigenous sediment while the 

northeastern GoM is characterized by carbonate. In addition, the outflows of the Mississippi and 

Atchafalya rivers may also serve as a barrier for dispersal for coastal organisms. In support of this 

observation, genetic differences have been observed between northeastern and northwestern 

populations of the thalassinidean Callichirus islagrande (Staton and Felder 1995), although we 

did not detect this regional barrier to dispersal in our genetic studies or the overall structure of the 

coral commnities.
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4.4.4.3 Depth Patterns

Cluster analysis and multivariate analyses of community composition suggest distinct faunal 

assemblages based on depth when observations are binned into 500 m depth intervals. Many 

factors co-vary with depth, which may determine the vertical distribution of fauna. In the 

Northeast Atlantic, for example, maximum depths of deep-water corals often reflect changes in 

the depths of water masses that have temperatures suitable for the corals. This was seen for deepwater gorgonian corals in the Northeast Channel of Canada (Mortensen and Buhl-Mortensen 

2004). 

Similar faunal zonation by depth has been seen in other studies. Distinct faunal assemblages based 

on depth have been observed in various seamount communities (Hoff and Stevens 2005; Samadi 

et al. 2007). Important faunal boundaries are thought to occur globally around 1000-1400 m depth 

(Howell et al. 2002), coinciding with the differences observed in this study. Similar faunal 

boundaries have been seen in asteroids in the North Atlantic at ~1,100 m (Howell et al. 2002), 

1,200-1,300 m for decapod crustaceans (Cartes and Sarda 1993), and 1,000 m for cerianthid 

anemones (Shepard et al. 1986). This boundary has been attributed to slope gradient, which is 

related to the formation of enhanced bottom currents through internal tides and can effect sediment 

transport and substratum type (Howell et al. 2002). A study of the deep-sea megabenthic fauna 

south of New England also showed similar breaks separating two distinct faunal assemblages 

between 1,290 m and 1,380 m and 1947 m – 2116 m (Haedrich et al. 1980). There is a peak in 

diversity for invertebrate megafauna in the northwest Atlantic between 1900 – 2,300 m (Howell 

et al. 2002; Rex 1981) and also a bathymetric boundary of a well-defined intermediate region of 

2,500-3,500 m where bathyal fauna meet, and overlap with, abyssal fauna (Haedrich et al. 1980; 

Howell et al. 2002). This depth zonation pattern is probably the result of a complex combination 

of physical factors and biological interactions (Gage and Tyler 1991).

Within the Gulf, differences in coral associate composition varied markedly with depth and 

biogeographic location. Yet while these differences exist, remarkable similarities in coralassociate taxonomic composition and relationships (e.g., ophiuroids on paramuricids and 

chirostylid crabs on antipatharian black corals) exist in deepwater coral ecosystems around the

world.
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4.5 USE OF IMAGERY AS BASELINE DATA FOR STUDY OF TEMPORAL 

CHANGE IN CORAL COMMUNITIES

One of the goals of using imagery in the way we did for this program was to establish study 

sites where one could study natural temporal changes in deep sea coral communities and 

also to establish baseline observation stations that could be used if needed in the future to 

evaluate potential anthropogenic-induced changes. When working in an environment as 

remote as the deep sea, one must consider the tradeoffs between many different approaches 

to monitoring corals and their communities. To best follow the health of entire marine 

communities, repeated surveys of randomly established transects has been the method of 

choice for many shallow benthic environments. These are most often established using 

scuba in relatively accessible habitats where the organisms of interest are present at 

relatively high density and where the established transect can be marked and relocated with 

relative ease. We successfully used the approach of large-scale transects for coral surveys 

in two of the sites we investigated, VK826 and VK906, where corals are present over fairly 

large areas and at moderate density (Section 4.1). This approach may also be fruitful at the 

deeper water site in AT 357 where gorgonians and Madropora are widespread over an area 

several hundred meters on each side. However, at all of the other sites surveyed below 400 

m depth the coral distribution is very patchy and random transects flown with an ROV 

most often missed the corals completely. Although these transects would be impossible to 

repeat exactly with current technology, additional random transects could be flown in the 

future at some sites and could detect large scale and/or significant changes in the 

communities (see section 4.1). This is one of the approaches that should be used for sites 

where it is appropriate.

To allow collection of photographic data at the community scale and to establish study 

sites for repeated monitoring in areas with very patchy coral development, we deployed 

markers and collected imagery for photomosaics over haphazardly chosen study sites of 

between 8 to 100 square meters with high coral density (Section 4.2). A repeat visit to 

thirteen of the stations after one year indicated that the stations are quite easy to relocate 

and are generally very stable. We found that detecting and quantifying coral growth after 

a single year is often problematic because of the very slow growth rate of the corals. 

However, at most stations this should be possible after a time period of 3 to 5 years. 

Documenting and understanding the patterns of natural temporal change in deep water 

coral communities will likely require decades of intermittent visits and study. These 

stations will be appropriate for monitoring natural change in the corals over decades and 

for quickly detecting abrupt change as might occur from potentially deleterious 

anthropogenic activities or accidents. Although there is considerable variation in the 

presence of mobile fauna between visits, after a few years of study a database will 

accumulate enough data to allow robust monitoring of these populations as well. 

One disadvantage of monitoring corals using down-looking imagery (either from transects 

or mosaics) is that many of the octocorals that can dominate some deep-sea coral 

communities are largely planar (“sea fans” and their allies). These types of corals are best 

visualized from a horizontal (“side-looking”) perspective. Four horizontal monitoring 

stations were established during the Lophelia II project (Figure 4-42 to Figure 4-45) prior 
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to the discovery of the impacted corals during the last dive of the last cruise to the natural 

coral site reported in White et al., 2012. This site is dominated by Paramuricea sp. and 

numerous horizontal monitoring stations of individual corals were established at this site.

A lesson learned through the study of the impacted corals near the Macondo well was the 

value of using individual coral colonies as monitoring stations. Since corals are attached 

to the sea floor and “sample” the water column for food and gas exchange, they are well 

suited to act as biological monitors for water quality in the normally quite stable deep-sea 

environment. Large deep-sea coral colonies are often many hundreds of years old, and 

thus natural mortality is a rare event. Because they are attached, when impacted they remain 

at the site of impact and provide a long lasting record of that impact. We have now returned 

six times to the corals discovered during the last dive of the 2010 Ron Brown cruise and 

have re-imaged most of the corals there to better understand the pathway and time course 

of recovery (orlack of recovery) after exposure to toxic hydrocarbons or dispersants 

(Appendix C-4). This methodology can also be used to provide direct measures of in-situ 

growth as the resolution of the images and branching patterns of the corals allow terminal 

branch growth (or loss) to be easily quantified. Similarly, the high resolution images allow 

quantification and monitoring of the entire assemblage of coral associates on each colony. 

A total of over 250 individual corals have been marked and imaged for monitoring in the 

deep GoM in connection with studies of the impact from the DWH spill.

A combination of both photomosaics and individual colony monitoring has proven to be a

powerful tool for study of temporal change in coral communities. The mosaics allow 

precise identification and localization of all colonies imaged as well as a record of mobile 

fauna at the site. When the site is revisited, re-imaging of the constituent coral colonies 

can be done very quickly and efficiently, and should any corals “disappear” this can be 

confirmed unequivocally. When working remotely in the deep sea, the combination of 

these monitoring strategies is very powerful and is recommended for future establishment 

of deep-sea coral monitoring stations.
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5 PHYLOGENETIC DIVERSITY AND CONNECTIVITY

5.1 OCTOCORAL COMMUNITY STRUCTURE AND PHYLOGENETIC DIVERSITY

5.1.1 Background

The GoM harbors a diversity of octocorals occurring from shallow waters to depths of at least 

3000 m. Octocoral diversity has been documented in taxonomic keys (museum records), two PhD 

dissertations (Giammona, 1978; Etnoyer, 2009) and a comprehensive checklist of GoM octocorals 

(Cairns and Bayer, 2009). From these accounts, it is known that at least 162 octocoral species 

occur in the entire GoM, but only 48% of these species are found in waters > 200 m (Cairns and 

Bayer, 2009). Despite these efforts to characterize the regional species pool in the GoM, the deep 

GoM remains poorly explored. Furthermore, whether octocorals assemble into distinct 

biogeographic provinces in the deep region largely remains unknown, but various biogeographic 

provinces have been proposed (Giammona, 1978; Cairns et al., 1993; Etnoyer, 2009). Faunal 

zonation with depth has been observed in the GoM across numerous taxonomic groups such as 

fishes (Powell et al., 2003), macrofauna (Wei et al., 2010), and chemosynthetic communities 

(Cordes et al., 2007; 2010). Whether these same zonation patterns extend to a hard bottom 

associated fauna such as corals is unclear. Discerning the distributions of octocorals in the deep 

GoM would help to elucidate deep-water biogeographic provinces, provide estimates of local 

diversity, and illustrate meta-community patterns; thus, providing critical data for the effective 

conservation of deep-water coral habitat.

Molecular barcoding combined with morphology is a useful approach to guide species 

identifications, while contributing to the growing efforts to discern the phylogenetic relationships 

of octocorals. Proper delineation of both population and species boundaries are also important 

when elucidating patterns in community structure. Testing hypotheses of coral community 

assembly in the deep sea first requires knowledge of the regional species pool from which coral 

assemblages are derived. Moreover, merging genetics into biodiversity estimates and community 

ecology enables conservation efforts to consider preserving genetic diversity and the evolutionary 

processes that generate this diversification (Moritz et al., 2002).

Lophelia II cruises enabled targeted collections of octocorals on the local scale using remotely 

operated vehicles and submersibles. We used a combination of molecular barcoding with 

morphological taxonomy to 1) identify a deep-water regional species pool, 2) provide estimates of 

diversity on both taxonomic and phylogenetic scales, and 3) add to the growing efforts of 

characterizing the phylogenetic relationships of octocorals. With this dataset, we were able to 

determine whether the community structure of octocorals is structured by 1) depth such that similar 

communities occur at sites in similar depths or by 2) location, such that similar communities occur 

in nearby sites. Furthermore, we were able to examine how phylogenetic diversity shifts with depth 

in the GoM and compare this diversity to sites beyond the GoM.
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5.1.2 Methods

5.1.2.1 Sample Collections

Specimens were collected at depths of 250-2,500 m during seven cruises in 2008-2011 from 31 

hard-bottom sites and 2 shipwrecks in the northern and eastern GoM during the Lophelia II project 

and additional projects using remotely operated vehicles [ROVs Jason, Seaview, Mohican 

Schilling UHD, (NRDA)] and human-occupied vehicles [HOVs Alvin (NSF RAPID) and JohnsonSea-Link (USGS)] (Figure 5-1 ). Although a few genera (Callogorgia and Paramuricea) were 

targeted for population genetics, we attempted to collect at least one individual of every species of 

octocoral observed during each dive. We did not, however, target pennatulaceans (sea pens) as

these species are associated with soft substrata; a habitat that was not the focus of the present study. 

One sea pen was, however, collected from GB299. Coral colonies were first imaged and then 

branches from each colony were snipped. 

All specimens were preserved onboard. Approximately 2-3 cm tissue samples per specimen were 

frozen at -80oC and preserved in both 95% ethanol (ETOH) (stored at -20 oC) and a high-salt 

EDTA preservative (stored at -80 oC). Voucher specimens of each individual were also obtained 

and either preserved in 95% ETOH or dried. Specimens were identified following numerous 

taxonomic keys (e.g., Deichmann, 1936; Grasshoff, 1977; Madsen, 1970; Bayer, 1961, 1981; 

Sanchez, 2005; Cairns and Bayer, 2002, 2004) and many were sent to taxonomic experts (J 

Sanchez, S Cairns, J Thoma, B Horvath, L van Ofwegen) for confirmation. Species were identified 

to the lowest possible taxon (see Appendices A-2, D-1 – D-2); many genera and families are 

currently undergoing taxonomic revision. Morphological identifications using Scanning Electron 

Microscopy (see Appendix D-2) were facilitated with molecular barcoding. Representatives of all 

species will be deposited in the Smithsonian Institution, DC.

Figure 5-1. Sites where octocorals (soft corals, stoloniferan corals, and gorgonians) were 

collected during surveys.
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5.1.2.2 Molecular Barcoding Methods

DNA was extracted using a Qiagen DNeasy kit. The extended mitochondrial barcode 

(COI+igr1+MutS) was sequenced for phylogenetic inference, as these gene regions are the most 

useful for species delimitation (McFadden et al., 2011). Approximately 850 base pairs (bp) from 

the 5’ end of the mitochondrial MutS gene and ~1000 bp of the COI+igr1 region were polymerase 

chain reaction PCR amplified (Table 5-1), following McFadden et al., 2006, 2011) and sequenced 

(Genewiz, Inc and UW-HtSeq). The sequences were edited, aligned by ClustalW and adjusted by 

eye by viewing amino acid alignments (BioEdit, MEGA). The gene regions were concatenated 

into a 2153 bp extended barcode and Bayesian (mrBayes) and Maximum Likelihood (GARLI,

Zwickl, 2006) analyses were performed. Using JModelTest (Guindon and Gascuel, 2003; Posada, 

2008), the General-Time-Reversible model plus the gamma distribution (GTR+G) was chosen as 

the most appropriate nucleotide substitution model for MutS (813 bp; AICc=8492.87); the 

transversion model plus invariable sites with a gamma distribution (TVM+I+G) was chosen for 

COI (752 bp, AICc=7342.72), and the transition model with a gamma distribution (TIM+G) was 

chosen for igr1 (AICc=5446.99).

Table 5-1.

PCR primers and protocols used to amplify targeted gene regions

Gene Sequence (5’ to 3’) PCR Profile a

COI+igr1 COII8068F1 CCA TAACAGGACTAGCAGCATC 94°:30 s, 60°:90 s, 72°:60 s

COII8068xF1 CCATAACAGGRCTWGCAGCATC 94°:30 s, 60°:90 s, 72°:60 s

SIRONAD6R1b, 2 ATTGCCCCTATGTTAGTTCTAG 94°:30 s, 54°:45 s, 72°:60 s

COIOCTR3 ATCATAGCATAGACCATACC

MutS ND4L2475F4 TAGTTTTACTGGCCTCTAC 94°:30 s, 51°:45 s, 72°:60 s

ND42599F3 GCCATTATGGTTAACTATTAC 94°:30 s, 51°:45 s, 72°:60 s

CO3BAM5657Fc, 4 GCTGCTAGTTGGTATTGGCAT 94°:30 s, 53°:45 s, 72°:60 s

ANTHOCORMSHb, 5 AGGAGAATTATTCTAAGTATGG 94°:30 s, 50°:45 s, 72°:60 s

MUT3458R6 TSGAGCAAAAGCCACTCC

aPCRs began with 5 min denaturing step at 94°C and ended with 10 min elongation at 72°C. 32 cycles were conducted 

for each 

bForward primer for scleraxonians (with the exception of Sibogagorgia).

cForward primer for bamboo corals (with the exception of Keratoisidinae clade S1)

1McFadden et al., 2004, 2Uda et al., 2011, 3France and Hoover, 2002, 4Brugler and France, 2007, 5Herrera et al., 2010, 

6Sanchez et al., 2003

Data were partitioned so that the appropriate models could be applied to each gene region in 

Bayesian and likelihood analyses. In MrBayes, the number of generations was set to 7,000,000, 

with a sampling frequency of every 100 generations followed by a burnin of 10,000 trees. The 

consensus tree was rooted at the midpoint and displayed in FigTree. Both posterior probabilities 

and bootstrap frequencies from likelihood analyses (calculated in the Sumtrees of the DendroPy 
205

v3 package, Sukumaran and Holder, 2010) are indicated on the consensus tree. We also created a 

phylogeny (as described above) of 199 MutS sequences (731 bp) to gain a more thorough picture 

of the relationships of the GoM haplotypes within the larger octocoral phylogeny. This analysis 

was restricted to MutS only because this gene region has been most often sequenced in previous 

studies. The most similar sequences to GoM haplotypes were downloaded from GenBank

(National Center for Biotechnology Information [NCBI]) and included in the analysis as well as 

many representatives across the octocoral sub-orders. Pairwise p-distances were calculated 

between all haplotypes for the extended barcode and the more inclusive MutS only (MEGA). 

5.1.2.3 Community Structure Analyses

We first constructed a species accumulation curve to estimate how well the deep-water regional 

species pool was sampled. (EstimateS; Colwell, 2005). The resampling based self-organizing 

background subtraction (SOBS) method was used to generate the expected number of species per 

sample and 95% confidence intervals (Gotelli and Colwell, 2001; Colwell et al., 2004). 

Multivariate analyses were used to determine differences in octocoral assemblages across sites 

(Primer 6, Clarke and Warwick, 2001; Clarke and Gorley, 2006). We delineated species 

boundaries between taxa by morphological characteristics and a criterion of 0.5% p-distance 

between putative species (see McFadden et al., 2011). Similarities between sites (B-Diversity) 

were calculated using the Sorensen Index on presence-absence data. A non-metric 

multidimensional scaling (MDS) ordination plot and a dendrogram based on hierarchical 

clustering of group average linking were created from the similarity matrix; similarity clusters 

defined by the dendrogram were overlain onto the MDS plot. In addition, because we did not 

incorporate any a priori knowledge of depth zonation, a SIMPROF test was used to determine 

whether any of the clusters were significantly dissimilar from one another. 

5.1.2.4 Phylogenetic Diversity Analyses

We calculated phylogenetic diversity at each site (Phylocom v4.2, Webb et al., 2008) using Faith’s 

index (FI) of diversity (Faith, 1992). FI is the sum of the branch lengths that connect all species 

occurring at a particular site within the phylogenetic tree. Both the GoM regional phylogeny 

(including all haplotypes) and the whole phylogeny based on MutS only were used for 

phylogenetic diversity calculations. Calculations were based on topology following Faith, 1992.

Phylogenetic distance shared by species at a site was substituted for number of species in the 

Sorensen’s Index to obtain a measure of phylogenetic betadiversity. Phylobetadiversity estimates 

between pairs of sites were then input into PRIMER and a MDS plot was created. 

5.1.3 Results and Discussion

5.1.3.1 Overview

435 specimens representing at least 52 species were collected from 33 sites in the GoM 

(Appendices A-2 through D-1). The species-accumulation curve indicated that the regional deepwater species pool was well sampled; however it appears that a few more species (~ 1 species per 

site) would be discovered with additionally surveyed sites (Figure 5-2).
206

Figure 5-2. Species-accumulation curve (dotted line) and 95% confidence intervals (solid lines).

Five of the six sub-orders of Alcyonacea (sensu McFadden et al., 2010) were represented in 

collections. Although one pennatulacean was collected, we excluded this soft-substrate associated 

species from analyses because of the focus on hard-bottom areas in this study. Holaxonians and 

calcaxonians were the most diverse groups of octocorals collected, representing at least 16 and 17 

species, respectively. The genera Callogorgia and Paramuricea were the most widespread and 

abundant octocorals observed in the GoM. Callogorgia was limited to the upper to middle slope, 

while Paramuricea was more abundant at deeper sites along the middle to lower slope (~1,000-

2,500 m). Bamboo corals (Isididae) were also common and occurred in shallow and deep waters 

(250-2,500 m); however, colonies were lacking from most mid-slope depths (~500-1,000 m). 

Scleraxonians were well represented in collections with eleven species, including the genera 

Corallium, Paragorgia, and Sibogagorgia. An additional three sub-species collected appear to be 

endemic to the GoM: Chelidonisis aurantiaca mexicana (Isididae), Callogorgia americana delta 

(Primnoidae), and Anthomastus robustus delta (Alcyoniidae).

5.1.3.2 New Records and New Species

A total of 12 species collected were previously not known to occur in the GoM (Cairns and Bayer, 

2009), thus the geographic ranges of several taxa were extended (AppendicesA-2 to D-1). These 

new records include: one stoloniferan (Clavularia rudis), at least 4 scleraxonians (Corallium 

niobe, Paragorgia regalis, P. johnsoni, Sibogagorgia cauliflora), two holaxonians (Paramuricea 

biscaya, Swiftia pallida), and three chrysogorgiids (Chrysogorgia averta, Iridogorgia splendens, 

I. magnispiralis). Further, during the Okeanos cruise in the GoM in 2012, Metallogorgia 

melanotrichos was observed in DC673. Many of these octocorals appear to have worldwide 

distributions; for instance, several have been collected off New Zealand (Sanchez 2005) and the 

North Atlantic Seamounts (Thoma et al. 2009; Pante et al., 2012).
207

At the very least, 4 new species of octocorals were collected; however, there may be up to 4 

additional new species (Anthothela sp. 2-3, Stoloniferan sp. 1 and 2; Appendix D-1). One new 

scleraxonian species was collected from the Gulf Penn wreck, where it was blanketing portions of 

the wreck (Figure 5-3). This species was also collected at VK826, VK906, and the West Florida 

Slope and was subsequently found in collections from Lophelia I. 

Figure 5-3. New species of scleraxonian growing on the Gulf Penn wreck.

One new species of Anthothela was collected at GB535 (Figure 5-4). Further, potentially two 

additional Anthothela spp. represent new species. Anthothela and the un-described species of 

scleraxonia are being described by Kirrily Moore (CSIRO, Univ. Tasmania) as part of her PhD 

Dissertation. 
208

Figure 5-4. Photo of Anthothela nov. sp. 1 at GB535.

Two individuals representing a newly described family of soft coral were collected from the West 

FL Slope (Figure 5-5). These species represent two new species of Aquaumbridae. Aquaumbridae 

is a family of soft coral (Alcyoniina) that was first described from the Pacific, off of Isla de Coco, 

Costa Rica in 300 m depth (Breedy et al., 2012). This family groups in the Holaxonia-Alcyoniina 

clade, and its closest known relative appears to be a holaxonian, Alaskagorgia.

Figure 5-5. Photo of Aquaumbridae from the W FL Slope.

One unidentified stoloniferan was collected from GB535, and potentially represents a new species. 

This species was found growing on a hexactinellid sponge (Figure 5-6).
209

Figure 5-6. Unidentified stoloniferan growing on a glass sponge.

5.1.3.3 Molecular Barcoding

We used a molecular barcoding approach combined with morphology to delimit species 

boundaries and to obtain an estimate of the phylogenetic diversity of corals in the GoM. Further, 

barcoding octocorals from the GoM allowed us to contribute to the growing efforts of octocoral 

phylogenetics, including adding sequence data on new, rare, and poorly sampled taxa. Many 

sequences that we obtained were not in GenBank nor were any close relatives in GenBank. Of the 

435 specimens collected, 422 were successfully barcoded, resulting in 64 unique COI+igr1+MutS

haplotypes; which now represent 20% of the octocoral barcodes in the entire NCBI GenBank 

database (Figure 5-7). We were successful in amplifying the extended barcode with different 

primer pairs (Table 4-1) for 420 specimens; however, COI+igr1 could not be amplified for species 

in the genus Anthomastus. MutS alone differentiated 59 haplotypes and COI+igr1 distinguished 

only 56. For the majority of species, the same haplotype was observed among all individuals, 

although there are a few exceptions (Figure 5-7). Although genetic distances of >1% most often 

indicate different species, those with genetic distances of 0.5-1% warrant additional attention 

(McFadden et al., 2010). In most cases, species delineations between sister taxa were achieved by 

coupling the minimum p-distance of 0.5% with distinguishable morphological characteristics; 

however a few problematic sister taxa are still unresolved. In fact, many of the genera collected in

this study are currently undergoing taxonomic revision. 
210

Bayesian and maximum likelihood analyses recovered similar topologies, and the majority of 

nodes were strongly supported (>90% posterior probabilities and bootstrap values). However, 

maximum likelihood analysis was unable to resolve a few polytomies that were situated toward 

the base of the tree. Two clades consisting of Holaxonia-Alcyoniina-Stolonifera (with Anthothela) 

(Clade 1) and Scleraxonia-Calcaxonia (with Anthomastus) (Clade 2) were strongly supported 

(100% posterior probability) (Figure 5-7).

These recovered clades are consistent with previous phylogenetic analyses (McFadden et al., 

2006). We also recovered interesting and new patterns within the phylogeny including: 1) the 

polyphyly of the Isididae with Chelidonisis a. mexicana occurring basal to the calcaxonians, 2) the 

basal position of the shallower occurring, Scleracis guadalupensis relative to the deep-water 

Swiftia clade, and 3) the close relationship of Swiftia with shallow water gorgoniids. 

Figure 5-7. Phylogenetic inference of the extended barcode (COI+igr1+MutS) of GoM deepwater octocorals. Consensus tree based on Bayesian analysis with posterior 

probabilities (above nodes) and bootstrap values (below nodes) indicated on tree. 

Posterior probabilities are >90% (*) unless indicated. Tree was rooted at the midpoint.

5.1.3.4 Diversity and Community Structure

5.1.3.4.1 α-Diversity

Overall, species richness at sites in the deep GoM was fairly low, with 1-12 species occurring at 

each site (Figure 5-8). 
211

Figure 5-8The deepest sites (2100-2500 m) contained the most number of species, with 12 species 

at DC673 and 10 species at DC583, followed by the shallowest (<325 m) site, GC140, with 8 

species and a site on the W Fl Slope (525 m) with 8 species. Peaks in species richness at the 

shallowest (< 325 m) and deepest (> 2100 m) sites sampled contrasts with other faunal diversity 

patterns in the GoM. In chemosynthetic tube worm and mussel communities, diversity peaks were 

evident at ~1,400 m and 500-600 m with a marked decrease at 2000 m (Cordes et al., 2010). 

Diversity peaks were also evident at 1400 m in soft sediment macrofaunal communities 

(Pequegnat, 1983), whereas in fishes, species richness steadily decreased with increasing depth 

(Pequegnat et al., 1990; Powell and Haedrich, 2003). The observed peak at the shelf-slope 

transition at GC140 for octocorals likely represents a merging of fauna, and may be attributed to 

mid-domain effects (Colwell and Lees, 2000). Some of the species collected at the shallow GC140 

site are also known to occur on the continental shelf (C. gracilis, S. guadalupensis). The octocoral 

species richness peak at ~2,000 m is similar to other diversity patterns in the deep North Atlantic 

(see Rex and Etter, 2010). For octocorals, this diversity peak may be due in part to evolutionary 

processes. The majority of species occurring at these depths were from two closely related families, 

the Isididae and Chrysogorgiidae, the latter of which diversified in the deep-sea (Pante et al., 2012). 
212

Figure 5-8. Species richness by average site depth.

Combining phylogenetic information into diversity estimates has advantages over taxonomic 

diversity alone, including allowing for the consideration of evolutionary history into local or 

regional comparisons of biodiversity, instead of conventional species richness (Faith and Baker, 

2006). Faith’s index of phylogenetic diversity also indicated high phylogenetic diversity at the DC 

sites, with the addition of GC852 (1400 m) and the upper slope sites (~450 m), VK906, VK826 

and MC751. In contrast, most mid-slope sites, (600-1,100 m) harbored the fewest species (1-3 

species), but had varying phylogenetic diversity (10-26). The few species at these sites were from 

genetically distant clades. Furthermore, although species richness was lower at MC751 and VK826 

compared with that of the shallower GC140 site, phylogenetic diversity was higher at these sites 

compared to GC140 based on the extended barcode. Interestingly, most of the species present at 

GC140 appear to occupy basal positions within clades compared to species from MC751 and 

VK826. This suggests that the shelf-slope transition may be an area of early divergence in 

octocorals, with only a subset of these species able to colonize the deep sea. 

5.1.3.4.2 β-diversity

Sorensen’s Index of taxonomic β-diversity revealed seven distinct species assemblages that were 

80-95% dissimilar from one another (Figure 5-9). Five of these assemblages were associated with 

five depth zones: <325 m, 325-425 m, 425-600 m, 600-1,100 m, and 1350-2400 m. Significant 
213

differences between these depth zones were evident (SIMPROF, <0.05), with a few exceptions. 

First, two GC sites, GC234 (493 m) and GC235 (530 m), grouped with sites occurring at 600-1100 

m depth at the 80% similarity level. This was likely due to C. a. delta occurring at GC234 and 

being the only species at GC235 (530 m), GC249 (777-790 m), and MC885 (623-637 m); 

Paramuricea sp. type B3 and Chrysogorgia sp. type 1 were also common at sites in depths of 600-

1100 m. Second, although occurring within the 400-600 m depth zone, assemblages at the Gulf 

Penn (541 m) and WFL4 (507 m) were significantly different from the other sites (SIMPROF, 

p=0.002) because only one species, scleraxonian nov. sp., occurred at these two sites. 

Further assemblage structure was evident within three of the depth zones, and some within-depth 

groupings were significantly different (Figure 5-9). Within 325-425 m, the octocoral assemblage 

at VK862 was significantly different from GB299 and VK906 (SIMPROF, p=0.006). All three 

sites shared one species, C. a. americana, but no other octocorals were present at VK862. The 

species assemblage at GB299 and VK906 also included N. dissidens, M. cf. hirta, Paramuricea 

sp. type E, and Keratoisidinae S1. Within 425-600 m, the assemblage structure at the West Florida 

slope (WFS) differed from sites to the west at a dissimilarity (Sorensen’s Index) of 70%; however, 

this pattern in assemblage structure was not significantly different (SIMPROF, p>0.05). Species 

assemblages within this depth zone of 425-600 m included Muriceides cf. hirta, cf. Muriceopsis 

sp., Paramuricea sp. type A and C. a. mexicana, but Plumarella dichotoma/pellucida (two 

morphological species with identical haplotypes) occurred only at the WFS whereas C. a. delta 

occurred to the west. Within 1,350-2,400 m, assemblage differences were evident with two distinct 

assemblages at 60% dissimilarity. DC sites 583 and 673 were significantly different from MC294, 

GC852, MC297 and MC388 (SIMPROF, p=0.04). Although P. biscaya and C. rudis occurred at 

all deep (>1300 m) sites, the presence of S. cauliflora, C. averta, Iridogorgia spp., and several 

isidids at the DC sites influenced assemblage patterns. This reveals the presence of an additional 

depth break at 2,100 m. 
214

Figure 5-9. MDS plot with distance between points representing Sorensen’s 

Index of Similarity. Assemblage similarity at > 20 (dotted line) and 

35% (solid line) are indicated. Circle size denotes average site depth. 

Stress=0.06.

Biogeographic provinces have been previously proposed for numerous taxonomic groups in the 

GoM, and some of these boundaries can be confirmed or expanded upon for deep-sea octocorals. 

Giammona (1978) suggested that octocorals assemble into six zones: sub-tropical, western Florida, 

northern, western, southeast Mexican coast, and an oceanic or deep-sea assemblage. Increased 

diversity at some stations in the northern GoM suggested an additional east-west boundary across 

the Mississippi River Delta. Although we did not observe the east-west break in coral community 

structure in the northern GoM, perhaps due to limited sampling west of the Green Canyon sites, 

we did find that mid-slope octocoral communities differed between the West Florida Slope and 

the remaining mid-slope communities in the northern GOM. The GoM Loop Current may serve 

as an oceanographic barrier to dispersal of larvae originating in the northern GoM, but also as a 

conduit of exchange between the GoM and the Caribbean Sea. 

Bathymetry, or the variables associated with bathymetry, is the primary factor responsible for 

patterns observed in octocoral community structure. Expanding on Giammona (1978) who 

proposed one, extensive deep-sea coral assemblage, Etnoyer (2009) used museum records to 

demonstrate that the deep-water assemblage can be divided into at least three provinces that range 
215

from 200-800 m, 800-1,600 m, and > 1,600 m. The assemblage patterns observed in the present 

study further refine the proposed depth provinces, with additional breaks on the upper to lower 

slope at 300, 400, 600, 1,000, 1,350, and 2,100 m. These zones are more similar to depth zones 

noted for other taxa in the GoM, such as soft sediment macrofauna (Wei et al., 2010), 

chemosynthetic communities (Cordes et al., 2007, 2010), and megafaunal invertebrates and fishes 

(Pequegnat, 1983; Pequegnat et al., 1990; Powell and Haedrich, 2003). However, the additional 

depth breaks observed across the upper to middle slope, particularly < 1,000 m, appear to be unique 

to deep-water octocorals in the GoM. The refined community boundaries are likely the result of 

targeted exploration of deep GoM hard substrates. Soft substrate species may be less specialized, 

and possibly have broader depth distributions than those species associated with hard substrates, 

as observed in sea pens off of Newfoundland (Baker et al., 2012). The question of whether these 

depth breaks are ubiquitous throughout the entire GoM awaits further exploration along the Texas 

and the Mexican coasts as well as through the Yucatan and Florida Straits. Regardless, depth 

zonation is apparent and predictable in the deep-water octocoral assemblage and plays a more 

important role than geographic distance in structuring octocoral communities, a pattern also 

observed in GoM chemosynthetic communities (Cordes et al., 2007).

We further expanded our analyses to examine the phylogenetic differences of species among sites. 

Preliminary estimates of phylo-betadiversity indicated that larger depth differences between pairs 

of sites had higher dissimilarity in phylogenetic structure (Figure 5-10). Furthermore, patterns in 

phylo-betadiversity illustrated that the relatedness of species shifts with increasing depth in the 

GoM, and the deepest sites harbor a greater number of closely related species compared to the 

shallower sites. In situ diversification of isidids and chrysogorgiids at the deepest sites appear to 

be driving these patterns.

Figure 5-10. . MDS plot with distance between points representing Sorensen’s Index of 

Phylogenetic Similarity (mean branch length substituted for species in Sorensen’s 

Index). Assemblage similarity at > 20 (dotted line) and 35% (solid line) are indicated. 

Circle size denotes average site depth.
216

5.1.3.5 Regional Comparisons of Communities 

Limited samples collected during a 2009 USGS cruise off the southeastern US allowed us to 

examine the similarity in phylogenetic diversity between octocorals collected in the GoM with 

octocorals collected off of Cape Canaveral (CC) FL in two depth zones (400-500 m, and 600-800 

m). Although further sampling off of CC will likely yield additional data, these results provide a 

first glimpse into biogeographic differences between the Atlantic and the GoM. Using only 

mtMutS, seven haplotypes were amplified from off CC from 15 samples (Figure 5-11). In general, 

each haplotype represented a unique species; however, mtMutS haplotypes were identical within 

two species of Plumarella (P. aculeata P. laxiramosa; identified by S. Cairns); additional 

sequencing is needed to resolve whether this Plumarella complex contains 1 or 2 species. 

Plumarella spp. was the only coral sequenced in the shallower depth zone off CC (400-600 m), 

and this is an abundant genus in this depth range off eastern FL.

The differences in phylogenetic diversity between the CC and GoM sites were apparent, with novel 

haplotypes collected off CC; only two haplotypes were shared between the GoM and the CC sites 

(P. pellucida/dichotoma, Muriceides cf. hirta). Plumarella aculeata and P. laxiramosa were 

collected off CC and did not occur on the WFS, where Plumarella dichotoma/pellucida (two 

morphological species with identical haplotypes) were abundant. However, P. 

aculeata/laxiramosa were collected in slightly shallower depths at the CC site (~400-440 m) than 

the WFS, indicating that this species may prefer shallower depths compared to its congeners. This 

is further supported with the collection of Plumarella pellucida/dichotoma off CC, at a depth of 

491 m. This depth range is similar to the depth range on the WFS where Plumarella occurred (488-

595 m), indicating that these differences may be a result of depth. The remaining species sequenced 

from CC were collected at depths of ~750 m: Lepidisis sp. D1b, cf. Muriceopsis sp. type B, 

Muriceides cf. hirta 1d, and Placogorgia cf. placomus. Muriceides cf. hirta appears to have a wide 

distribution, both geographically and bathymetrically. This species was collected throughout the 

GoM-from GB535 to WFS -at depths ranging from ~410-540 m. Furthermore, increased genetic 

diversity within this species is apparent (four haplotypes), and the Muriceides cf. hirta type 1d 

haplotype occurred at both CC and in the GoM. The other three haplotypes (Lepidisis D1b, cf. 

Muriceopsis type B, and P. cf. placomus) collected were not found in the GoM, although 

genetically similar haplotypes occurred. In general, differences in genetic diversity occurring 

between these regions suggests a biogeographic break between the continental slope of the GoM 

and the southewast US however, additional sampling off the southewast US and particularly on 

the WFS are needed to gain a more thorough picture of 1) whether differences in genetic diversity 

and community structure are due to biogeographical or bathymetric breaks and 2) where these 

breaks occur. 
217

Figure 5-11. Neighbor-joining tree of mtMutS haplotypes 

sequenced from collections off Cape Canaveral, 

FL (in bold) and genetically-similar haplotypes 

sequenced from the Gulf.

5.1.4 Conclusions

The molecular barcoding approach allowed us to identify distinct species associated with hard 

substrates. Further, a considerable number of species that were not known to occur in the region 

were documented. Because cryptic species are often revealed and morphological characteristics of 

species are still being resolved, it is important to continue incorporating genetic techniques into 

identifying species boundaries, and thus community boundaries, of deep-sea species. The speciesaccumulation curve did not quite reach an asymptote, indicating that additional species will likely 

be collected with additional sampling. Moreover, our results indicated that octocoral communities 

assemble primarily into distinct bathymetric provinces in the deep GoM, followed secondarily by 

location as the WFS sites differed from the sites in the northern GoM. Our data also indicate that 

phylogenetic history plays an obvious and primary role in octocoral community assembly in the 

deep sea.

Plumarella sp.

Plumarella sp.

Plumarella sp.

Plumarella sp.

Plumarella aculeata

Plumarella sp.

Plumarella laxiramosa

Plumarella aculeata

Plumarella sp.

Plumarella pourtallesi

Plumarella pelluicida/dichotoma

Plumarella pellucida

Keratoisidinae S1a

Keratoisidinae S1b

Keratoisidinae S1c

Keratoisidinae nrJ2a

Lepidisis kerD1b

Lepidisis kerD1a

Keratoisidinae N1a

Keratoisidinae I1

Keratoisidinae I2

cf. Muriceopsis sp. type B

cf. Muriceopsis sp. type A

Muriceides sp. 3

Muriceides cf hirta 1a

Muriceides cf hirta 1c

Muriceides cf hirta 1b

Muriceides cf. hirta 1d

Muricedes cf. hirta 1d

Muriceides sp. 2

cf. Echinomuricea sp.

Paramuricea type H

Placogorgia cf. placomus

Paramuricea sp. type E

Paramuricea sp. type A

Paramuricea sp. type B3

Paramuricea sp. type B2

Paramuricea sp. type B1a

10
218

5.2 GENETIC DIVERSITY OF TWO COMMON OCTOCORALS

5.2.1 Background

Lophelia II surveys indicated that two common octocoral genera occur along the continental slope 

in the GoM. Callogorgia is common at depths ranging up to 1,000 m whereas Paramuricea occurs 

at depths up to 2,400 m, but is most common at deeper sites (>1,000 m). These two genera increase 

habitat heterogeneity on the continental slope and have potentially symbiotic relationships with 

ophiuroid brittle stars. Callogorgia also serves as egg-laying substrate for scyliorhinid catsharks 

(Etnoyer and Warrenchuk 2008). Because of their abundance and ecosystem importance in the 

GoM, it is imperative to understand species boundaries within these two genera, as well as their 

genetic connectivity across the GoM. Therefore, mitochondrial (mtMutS, cox1+igr), nuclear 

rDNA (28S), and microsatellite loci coupled with morphological data are being used to understand 

the boundaries of populations and species within these genera. Genetic data will provide insight 

into whether populations are structured by depth and/or by distance, while enabling the 

determination of migration pathways and source populations. 

5.2.2 Methods 

5.2.2.1 Morphological Identification

Approximately 2-3 cm tissue samples were obtained from each specimen (165 Callogorgia, 103 

Paramuricea), frozen at -80oC and preserved in both 95% ETOH (stored at -20 oC) and a high-salt 

EDTA preservative (stored at -80 oC). Voucher specimens of each individual were preserved in 

95% ETOH or dried. Species were identified using morphological characteristics (Bayer 1982; 

Cairns & Bayer 2002; Cairns 2010; Grasshoff 1977). Scanning election microscopy (Quanta 600 

FEG at the Penn Nanotechnology Regional Center) was used to identify morphological differences 

between haplotypes. 

5.2.2.2 Phylogenetics

5.2.2.2.1 Callogorgia

DNA was extracted using a Qiagen DNeasy kit. The extended mitochondrial barcode 

(cox1+igr1+mtMutS) was sequenced for 159 individuals; 6 individuals could not be barcoded 

because of tissue preservation issues. Approximately 850 bp from the 5’ end of the mitochondrial 

mtMutS gene and ~1000 bp of the cox1+igr1 region were amplified through PCR (following 

McFadden et al. 2006, 2011) and sequenced (Genewiz Inc and UW-HtSeq). We also amplified 

and sequenced an ~810 bp fragment of the nuclear 28S ribosomal gene in each species following 

McFadden and van Ofwegen (2012). All sequences were edited, aligned by ClustalW (gap opening 

penalty= 25, extension penalty=15) and visually adjusted by viewing amino acid alignments in 

MEGA v5 28S was aligned using the L-INSi method (gap opening penalty=1.53; extension 

penalty=0.07) in MAFFT and amino acid alignments were visually adjusted. The mitochondrial 

gene regions were concatenated into a 1708 bp extended barcode and 28S resulted in a 799 bp 

alignment. Uncorrected p-distances were calculated for both mitochondrial and nuclear loci 
219

(MEGA v5). Bayesian analysis (BEAST) was used to determine the phylogenetic relationships of 

Callogorgia, including two species collected from outside the GoM: C. verticillata and C. gilberti. 

Data were partitioned so that the appropriate nucleotide models could be applied to gene regions. 

The maximum clade tree was rooted with the outgroup Plumarella sp. and displayed in Figtree.

5.2.2.2.2 Paramuricea 

DNA extractions were performed using the Qiagen DNeasy Blood and Tissue Kit. The extended 

mitochondrial barcode (COI+igr1+MutS) was sequenced following McFadden et al. (2006, 2011). 

Approximately 850 bp from the 5’ end of the mitochondrial MutS gene and ~1000 bp of the 

COI+igr1 region were PCR amplified and the resulting sequences were edited, aligned by 

ClustalW and adjusted by eye by viewing amino acid alignments (BioEdit, MEGA). The gene 

regions were concatenated into a 1602 bp extended barcode. Pairwise p-distances were calculated 

between all haplotypes (MEGA v5). A median joining network of haplotypes was created 

(Network v 4.6, http://www.fluxus-engineering.com/). 

5.2.2.3 Microsatellite Marker Development

Two individuals each of Paramuricea and Callogorgia were sequenced on a full plate on Roche454 (Engencore, Colombia SC), resulting in ~1 million reads (Table 5-2). A greater number (~2X) 

of reads were obtained for Callogorgia compared with Paramuricea. Average lengths of reads 

ranged from 340-348 ±147-148 (s.d.) bp. Reads were input into the QDD2 (Meglecz and Martin 

2011) program, which is a program that enables microsatellite selection and subsequent primer 

design (PRIMER 3). Table 5-2 illustrates the results from QDD2. 556 to 1,438 unique reads and 

contigs were obtained for each individual that had optimal primers and microsatellites that repeated 

at least 5 times and had motifs ≥3 (e.g., AGT). Reads containing microsatellites were BLASTed 

against one another and these reads were then searched for polymorphic microsatellites. From a 

list of 114 potential loci that had good primers, 39 primer pairs were ordered and tested for 

amplification across C. a. americana and C. a. delta. Forward primers were ordered with unlabeled 

tails (T1-T4), and these same tails were ordered with fluorescent labels. All loci were amplified 

using the following PCR profile: initial denaturation: 94 ° C at 5 min, followed by 32 cycles of 94 

° C 20 s, 54 ° C at 20 s, 72 ° C at 30 s, followed by a final elongation of 72 ° C at 30 min. After locus 

testing across populations, cycle number was increased to 45 for reactions and annealing 

temperatures are in progress of being optimized for ideal amplification of selected loci. The 

following final concentrations are used in 10ul PCR reactions: 10-20 ng DNA template, 1uM 

dNTPs, 1X Buffer, 0.15 uM Reverse Primer, 0.15 uM fluorescent-labeled tag (PET, 6FAM, NED, 

VIC), 0.04 uM Forward Primer, 2.5 mM MgCl2, and 0.1 units Taq. Forward primers with 

fluorescent tags (PET, NED, VIC, 6FAM) were ordered for the selected loci (see Results) for 

multiplexing. PCR products were pooled and analyzed on an ABI 3130XL Genetic Analyzer at 

the University of Pennsylvania. Fragments were sized using the microsatellite plug-in for Geneious 

with GS500LZ size standards (Applied Biosystems, Inc.). The Microsoft Excel add-on GenALEx 

was used to determine departures from Hardy Weinberg, and observed and expected 

heterozygosity at each locus. Genetic distances between pairs of individuals were calculated and 

plotted in a Principal Coordinate Analysis. An Analysis of Molecular Variance (AMOVA) was 

used to determine whether FST values were significant. FST is the proportion of the total genetic 
220

variance contained in a subpopulation (the S subscript) relative to the total genetic variance (the T

subscript). Values range from 0 to 1, with High FST indicating a considerable degree of 

differentiation among populations. Pairwise FST values were coupled with pairwise geographic 

distances and depth differences between sties to test whether populations are isolated by depth 

and/or by distance in the GoM. Using the IDB on the Web program, a Mantel test was used to test 

for significant correlation between depth and geographic distance with genetic distance (FST).

Although efforts have been primarily focused on Callogorgia, we also tested population 

differentiation in Paramuricea. For Paramuricea, 45 potential loci were discovered and 29 were 

subsequently ordered and weretested for amplification in Paramuricea type B3 and P. biscaya. 

Table 5-2. 

Reads obtained from 454 sequencing and subsequent results from a microsatellite 

discovery program (QDD2, Meglecz and Martin 2011)

Individual Total # 

Reads 

Size Range Unique Reads 

(>80 bp) with 

MSAT5+

Unique Reads 

(>80 bp) with 

Primers 

Unique Reads

(>80 bp) with 

Primers & MSAT 

Motif >3

C. am delta 

(MC751)

430,346 24-743 

(347±147)

12,306 7,680 1,438

C. am delta 

(VK826)

293,081 24-708

(348±148)

10,056 6,240 1,290

P. biscaya B1

(MC294)

258,590 24-1086

(347±148)

3,938 2,619 569

P. biscaya B2

(GC852)

184,264 26-896

(340±149)

3,181 2,188 556
221

5.2.3 Results and Discussion

5.2.3.1 Taxonomic Status and Phylogenetic Relationships

5.2.3.1.1 Callogorgia

Extensive GoM collections (n=165 individuals) yielded three Callogorgia taxa: C. americana 

americana (n=31), C. americana delta (n=122), and C. gracilis (n=12). Sclerite counts and 

structures were useful in species identification (Figure 5-12). Taxonomic designations based on 

morphology were further confirmed with the occurrence of a unique mitochondrial molecular 

barcode (cox1+igr1+mtMutS) obtained for each taxon; no haplotype variability was observed 

among individuals within a taxon. Of all Callogorgia spp. sequenced in this study, putative species 

were 0.4-1.6% genetically divergent (p-distance) at the extended mitochondrial barcode (Table 

5-3). P-distances obtained at 28S were generally higher, ranging from 0.38-4.53% (Table 5-3). 

Total genetic divergences at both mitochondrial and nuclear loci ranged from 0.40-2.45% (Table 

5-3). The USNM1116119 voucher specimen of C. gracilis was identical to the GoM C. gracilis. 

Figure 5-12. Morphology of GoM Callogorgia spp. Scanning electron 

microscopy images of polyps and whole colony images for (A-C) 

Callogorgia gracilis, (D-F) C. a. americana, and (G-I) C. a. delta. 500 

um scale bar indicated.

Resolving the taxonomic status of the sub-species C. americana delta and C. a. americana was in 

part the impetus for this study, as these sub-species are among the most commonly occurring 

octocoral species in the deep GoM. In 2002, Cairns and Bayer delineated these two sub-species 
222

based primarily on differences in sclerite structure and distribution. Callogorgia a. americana was 

previously thought to be restricted to the Caribbean Sea, Florida Straits, and southern GoM while 

C. a. delta was a northern GoM endemic. The extensive records provided in this study 

demonstrated that both taxa are present in the northern GoM and they differ genetically and 

morphologically. Further, these two species inhabited different depth zones (C. a. americana: 

<425 and C. a. delta: 425-1,000 m), at least in the GoM. This depth differentiation is possibly the 

result of parapatric speciation along an environmental gradient in depth, a pattern seen in other 

corals (Prada and Hellberg 2013). Alternatively, niche differences in Callogorgia could have 

accrued after speciation, and the observed distributions could either be due to historical 

colonization of C. a delta into deeper areas of the GoM followed by adaptation to depth-related 

variables or the result of competitive exclusion (e.g. for limited space) of one taxon from their 

congener’s respective preferred habitat.

Table 5-3.

Pairwise uncorrected p-distances (%) for Callogorgia species at (A) mitochondrial 

cox1+igr1+mtMutS, (B) nuclear 28S, and (C) both mitochondrial and nuclear loci

A C. gracilis C. verticillata C. a. americana C. a. delta

C. gracilis

C. verticillata 0.35

C. a. americana 1.47 1.41

C. a. delta 1.59 1.47 1.24

C. gilberti 1.18 1.06 0.82 0.41

B C. gracilis C. verticillata C. a. americana C. a. delta

C. gracilis

C. verticillata 1.25

C. a. americana 4.53 4.40

C. a. delta 3.78 3.65 1.63

C. gilberti 3.90 3.77 1.76 0.38

C C. gracilis C. verticillata C. a. americana C. a. delta

C. gracilis

C. verticillata 0.64

C. a. americana 2.45 2.36

C. a. delta 2.29 2.17 1.36

C. gilberti 2.05 1.92 1.12 0.40

Two pairs of sister taxa with allopatric distributions were recovered from the phylogeny: 1) C. a. 

delta with C. gilberti and 2) C. gracilis with C. verticillata (Figure 5-13). Sister taxa in both clades 

were only ~0.4-0.6% genetically divergent, just around the threshold (0.5% p-distance) provided 

by McFadden et al. (2011) for delimiting species boundaries. However, morphology combined 

with allopatric distributions suggests that these taxa are most likely distinct species. In 2010, 

Cairns synonymized C. gilberti with C. americana, noting that these two taxa were 

morphologically indistinguishable. Although sclerite counts overlap, it appears that counts in C. 
223

gilberti range somewhat higher, with 10-12 abaxial, 4-5 outer lateral and 2-3 inner lateral 

compared with 9-11 abaxial, 3-4 outer lateral, and 1-2 inner lateral in C. a delta. In addition, 

Callogorgia gilberti is known from off the Hawaiian Islands and Cross Seamount in 326-965 m 

(Cairns 2010) whereas C. a. delta had been described only from the GoM (Cairns and Bayer 2002). 

The sister species C. gracilis and C. verticillata also have allopatric distributions. Callogorgia 

gracilis has been previously documented from the GoM and throughout the Caribbean (Cairns and

Bayer 2002) whereas C. verticillata is only known from the eastern Atlantic and Mediterranean 

Sea. The presence of inner lateral sclerites and a greater number of outer later sclerites are 

characters distinguishing between C. gracilis and C. verticillata (Cairns and Bayer 2002). 

Figure 5-13. Maximum clade credibility tree of Callogorgia

at combined loci (cox1+mtMutS+28S) Posterior 

probabilities were all >90%. Numbers designate 

genbank sequences.

5.2.3.1.2 Paramuricea

Samples of 103 colonies of Paramuricea were collected for genetic and morphological analyses. 

Molecular barcoding techniques combined with morphology enabled identification of likely five 

species of Paramuricea in the northern GoM. Seven haplotypes of the extended barcode emerged 

within the Paramuricea genus and were 0.1-2.2 % divergent from each other (Table 5-4). 

Paramuricea type H was 1.7-1.8% divergent from the other Paramuricea haplotypes. 

Paramuricea types A and E were genetically quite similar (0.2% divergent), but morphological 

differences indicated that these likely represent different species (Figure 5-14). Paramuricea type 

A had thorny spindle-shaped coenenchymal sclerites (some bent) and elongated thornscales. In 

contrast, sclerites observed in Paramuricea type E were irregularly shaped and sized, and 

contained spindles and branched spindles. Four Paramuricea type B haplotypes were identical at 
224

MutS, but they differed in 1-2 bp polymorphisms at COI; B1a had an additional polymorphism in 

igr1 (0.1-0.2% p-distance). Although p-distances were low, morphological differences between 

type B3 and P. biscaya types B1, B1a, and B2 were identifiable (Figure 5-15).

Figure 5-14. Scanning electron microscopy of sclerite 

composition and structure of six haplotypes of 

Paramuricea with photos of colony morphology. Scale 

bar indicates 500 um.

Table 5-4. 

Pairwise uncorrected p-distances (%) for Paramuricea spp. at mt cox1+igr1+mtMutS

Type A Type E P. biscaya 

B1

P. biscaya 

B1a

P. 

biscaya 

B2

Type B3

Type E 0.19

P. biscaya B1 0.62 0.69

P. biscaya B1a 0.69 0.75 0.06

P. biscaya B2 0.50 0.56 0.12 0.19

Type B3 0.56 0.62 0.19 0.25 0.06

Type H 2.10 2.25 1.87 1.94 1.75 1.81
225

Figure 5-15. Median joining network of haplotypes collected in the GoM. Size of circle 

corresponds to total number collected. Number of substitutions is indicated by slash 

marks (except Type 1 to the remaining is indicated by a number 35).

Paramuricea type B3 differed by having bent spindle-shaped, coenenchymal sclerites and blunt 

thornscales whereas plate-shaped sclerites were found in P. biscaya and thornscales were more 

elongated compared with type B3. 

Although there was low genetic divergence in the extended mitochondrial barcode between 

Paramuricea types A and E and between Paramuricea types B3 and P. biscaya, there were 

consistent differences in sclerite morphology between the haplotypes, suggesting that these likely 

represent different species. Although additional genetic markers or genomic data are needed to 

confirm the species boundaries within this genus, the molecular barcodes used in this study 

allowed us to identify independent, phylogenetic lineages of Paramuricea. Furthermore, each 

putative species appears to inhabit specific depth zones in the northern GoM, with Paramuricea 

Type H at < 260 m, type E at 280-400 m, type A at 443-550 m, type B3 at 837-1,040 m, and P. 

biscaya at 1,370-2,400 m.

The mtMutS haplotypes of Paramuricea found in the GoM appear to be geographically widespread 

throughout the North Atlantic. Our haplotype designations correspond to those identified from the 

North Atlantic seamounts and along the continental margin off the northeast US coast, Norway, 

and in the Caribbean Sea (Thoma et al., 2009). The widespread distribution of these haplotypes 

suggests that, at the very least, historical dispersal of this genus occurred throughout the deep sea, 

which has been noted in other species of cold-water corals. Our population genetics studies using 

microsatellites are needed to examine further population differentiation within the GoM and 

beyond.
226

5.2.3.2 Microsatellite Analyses

5.2.3.2.1 Callogorgia

Of 39 primer pairs that were tested for amplification across individuals, 12 loci were polymorphic 

and consistently amplified in both C. a. delta and C. a. americana (Table 5-5). The number of 

alleles per locus ranged from 1-13, and the majority were private alleles within a species. Overall, 

there was low allelic diversity (mean 3.55 ± 3.08 s.d.) at most loci within a species, with the 

exception of GIR, GD1, EFD, and CYO. The low allelic diversity at both microsatellite and 

mitochondrial loci in both Callogorgia spp. in the GoM suggests that these species underwent a 

recent population bottleneck and/or the GoM was colonized by a few number of individuals. 

Severe reduction in population size can influence the genetic variation within and among 

populations, often resulting in reduced genetic diversity (e.g., Bouzat et al. 1998). In addition, five 

out of the 12 loci in C. a. delta showed either heterozygote excess (GIR, A50, EME, EFD) or 

deficiency (B3S) (Table 5-5). Heterozygote deficiency (low frequency of heterozygotes) is often 

indicative of small populations and/or inbreeding. However, more data are needed to confirm this 

as the lack of heterozygotes at B3S could also be to the presence of null alleles, which occur when 

mutations in the primer region prevent primer binding (Callen et al. 1993). The excess in 

heterozygosity (higher frequency of heterozygotes) at the four loci (GIR, A50, EME, EFD) is often 

indicative of higher genetic diversity; however, some studies have suggested that heterozygosity 

can increase at a few number of loci after a founder event or population bottleneck due to chance 

(Leberg 1992, Cornuet and Luikart 1996). More data are needed to test whether Callogorgia spp. 

in the GoM were established from just a few individuals (founder effect) or whether these species 

have undergone a recent population bottleneck.

Using a population genetic approach, Callogorgia americana americana and C. a. delta were 

clearly delimited based only on four loci (GD1, EME, DAV, JKM). Analysis of molecular variance 

(AMOVA) of the two species of Callogorgia revealed an FST value (genetic distance) of 0.374 

(P<0.001), demonstrating significant genetic differentiation between these two species. A 

principal coordinate analysis based on pairwise genetic distances (calculated in GenALEx) of 40 

Callogorgia spp. also revealed clear separation of the two species, as indicated by two separate 

clusters in Figure 5-16. Few of the same alleles were found in both species across the four loci. No 

alleles were shared at GD1 or DAV; 1 allele was shared at EME, and 1 allele was shared at JKM. 

Further data are needed to assess whether there are any hybrids of the two species of Callogorgia.
227

Table 5-5.

Locus name, primer sequences, type of fluorescent label on each forward primer, repeat motif, size range in base pairs. For each 

species, N=number of individuals genotyped, NA=number of alleles, HO =observed heterozygosity, HE=expected heterozygosity

and pHWE =p-value indicating departure from Hardy Weinberg equilibrium per locus using a Chi-Square Test. A Bonferroni 

adjustment was made to α. Significance (*) = p<0.004

Locus Motif Allele 

Sizes

Primers (5’-3’) Fluorescent 

Label/Tail

Species N NA NPA HE HO PHWE

CaC3L AAGT 217-229 F: AGGTGTTGCCTATAGACGTG

R: ACTAATTTGATAAATTGACAGT PET-T1

C. a. amer

C. a. delta

3

22

1

2

1

2

-

0.136

-

0.127

-

0.731

CaB3S AAT 228-243 F: CTGCAGCAATCTGGACTTAC

R: ATGATGCCGTTATTTTATCA 6FAM-T2

C. a. amer

C. a. delta

4

21

2

2

1

1

0.278

0.245

0.333

0.095

0.729

*

CaGIR AAAC 256-332 F: ATTTCGAAGACGAGGAACTC

R: ACTAGGGCTTAACATCCCTG VIC-T4

C. a. amer

C. a. delta

4

27

5

13

2

10

0.750

0.444

1.000

0.896

0.285

*

CaDAV ACG 164-179 F: CGATAACCGTTTGCATACTC

R: TGCGTAGTTATCGTAGTGGG NED-T3

C. a. amer

C. a. delta

18

83

4

2

3

1

0.560

0.353

0.667

0.361

0.322

0.828

CaA50 AAC 245-260 F: AACCCTGCCACTTCTAGTTT

R: CGCATCATTAACCTACATGG NED-T3

C. a. amer

C. a. delta

6

33

2

3

2

3

0.375

0.579

0.500

0.970

0.414

*

CaJWL AAAT 271-279 F: TTTTATCTGTATAGTTGAATTAAG

R: GAAGAGGGGACTACGCTAA NED-T3

C. a. amer

C. a. delta

15

64

1

4

0

2

-

0.283

-

0.266

-

0.960

CaFHM AAT 221-227 F: CTTTTACCAAACCAAGTCCC

R: CCTGCAAACTATCCTGATGA 6FAM-T2

C. a. amer

C. a. delta

11

33

2

2

1

1

0.351

0.485

0.273

0.500

0.458

0.866

CaGD1 ACAGCT 116-212 F: AAATTACTCCTTTTCCAAACT

R: TCTCATTACCGCTGTTTTGT VIC-T4

C. a. amer

C. a. delta

18

45

3

11

3

11

0.364

0.854

0.444

0.733

0.689

0.243

CaJKM AAC 255-264 F: CGATGGTTGGTCCATTAGTA

R: GCTAGCGGAGTATGACAATG 6FAM-T2

C. a. amer

C. a. delta

24

106

3

2

2

1

0.570

0.496

0.583

0.462

0.955

0.479

CaEME AGT 226-244 F: TTTCGTAGTTACCGTGCATC

R: CCATTTAAAACCACAGGTCA NED-T3

C. a. amer

C. a. delta

27

110

4

3

2

1

0.533

0.485

0.593

0.682

0.895

*

CaEFD AAT 159-216 F: TGCCTTTTACAGCAGAGCTA

R: TACACCGGTTACACCAGAAC VIC-T4

C. a. amer

C. a. delta

15

112

9

4

8

3

0.651

0.211

0.600

0.232

1.00

*

CaCYO AACT 154-190 F: CTTGTCGCATGTAATCCAAT

R: CCCGTTTAGATGTCAAACTT NED-T3

C. a. amer

C. a. delta

1

13

2

8

1

7

-

0.462

-

0.740

-

0.028

*Tails were added to the 5’ ends of forward primers as follows: T1: GGCTAGGAAAGGTTAGTG, T2: TCATACATGTCTCTCAGCGTAAAC, T3: ACCAACCTAGGAAACACAG, 

T4: GACTATGGGCGTGAGTGCAT
228

Figure 5-16. Principal coordinate analysis of Callogorgia americana americana (orange 

diamonds) and Callogorgia americana delta (blue squares).

To further examine whether Callogorgia americana delta is isolated by depth and/or by distance 

in the GoM, population differentiation was examined across seven sites. Five loci (GDI, EME, 

DAV, JKM, JWL) from 94 individuals were used for these preliminary analyses. The principal 

coordinate analysis based on pairwise genotypic distances (calculated in GenALEx) of 94 

Callogorgia a. delta revealed no clear separation of populations (Figure 5-17); however, most 

individuals from the deeper sites (>600 m) clustered together, with some individuals, particularly 

from MC885 and MC751, clustering with individuals in both deeper and shallower depths. The 

average pairwise FST value (genetic distance) was 0.091 (P=0.001) in Callogorgia a. delta across 

the entire GoM, suggesting overall, low population differentiation among sites in the northern 

GoM. Upon further examination of pairwise FST values, some genetic differentiation was apparent 

and significant between certain sties (Table 5-6), particularly GC246.and GC249 with the 

shallower GC235, MC751 and VK826; however, GC249 was also significantly different from 

GC338 and GC246, which are in approximately the same depth range (~800 m). This is likely due 

to the combination of few individuals genotyped at GC249, GC338, and GC246 and missing data 

at the GD1 locus for most of the individuals at GC249.
229

Figure 5-17. Principal coordinate analysis based on genotypic distances of Callogorgia 

americana delta across seven sites. Sites are color coded by mean depth (blue< 600 m, 

purple > 600 m).

Table 5-6.

Pairwise FST values among sites arranged by increasing depth. FST values in bold are 

significant (AMOVA, Bonferroni adjustment, p<0.003). 

MC751

(440 m)

n=27

VK826

(504 m)

n=18

GC235

(532 m)

n=7

MC885

(628 m)

n=16

GC249

(788 m)

n=16

GC338

(832 m)

n=4

GC246

(845 m)

n=6

VK826 0.023

GC235 0.113 0.000

MC885 0.051 0.051 0.114

GC249 0.090 0.102 0.165 0.056

GC338 0.152 0.088 0.056 0.181 0.164

GC246 0.223 0.119 0.057 0.182 0.192 0.160

Values closer to 1 indicate greater population differentiation. n=number of individuals 

genotyped and used in analyses. Average site depth of collections is noted in 

parentheses

Because of missing data at GC249, we removed this site from further tests of isolation by depth 

and distance. Isolation by depth tests indicated a trend for greater genetic differentiation with 

increasing depth differences between sites (Z = 380.7760, r = 0.3508 , p = 0.0760, Figure 5-18A). 

In contrast, no significant correlation was found with genetic distance and geographic distance (Z 

= 229.2670, r = -0.3034, p = 0.2490, Figure 5-18B). These results indicate that populations are 

likely structured by depth rather than distance in the northern GoM. These results contrast patterns 

observed in other foundation species in the deep GoM, such as those from chemosynthetic PCoA 2

PCoA1

MC751 440 m

VK826 504 m

GC235 532 m

MC885 628 m

GC249 788 m

GC338 832 m

GC246 845 m

Site Depth (m)
230

communities. Bathymodiolus childressi showed no population differentiation across a large depth 

range (~500-2,000 m) (Carney et al 2006) and Lamellibrachia luymesi showed weak, but 

significant population differentiation across the northern GoM (McMullin et al. 2010). However, 

collections of Callogorgia further to the west of Green Canyon might reveal population 

differentiation across the northern GoM. Nevertheless, isolation by depth within Callogorgia a. 

delta upholds the overall pattern that bathymetry is important in the evolution and ecology of 

octocorals in the GoM. 

Figure 5-18. Pairwise genetic differentiation patterns with respect to a) depth and b) geographic 

distance in Callogorgia americana delta. Large, dark blue circles indicate depth 

differences of >200 m between sites.

5.2.4 Conclusions

The combined molecular and morphological approach used allowed us to successfully delimit 

closely related species of two genera that are common in the GoM. Three species of Callogorgia 

are present in the GoM, C. gracilis, C. americana americana, and C. americana delta. 

Furthermore, mitochondrial and nuclear data indicated that the sub-species of C. americana are 

clearly distinct, and full species status is warranted, although there may be a few hybrids within 

sampled populations. Callogorgia spp. also clearly differentiate by depth, with further structure in 

C. a. delta across 400-1,000 m depth. Preliminary results suggest that Callogorgia either 

underwent a severe population bottleneck or the GoM was founded by relatively few individuals, 

but further analyses are needed to test this hypothesis. Our results to date also indicate that species 

of Paramuricea segregate by depth, with at least five species inhabiting specific depth zones in 

the GoM. Bathymetry, rather then geography, is important in population structure within both 

genera in the northern GoM.

B

y = -0.0003x + 0.1486

R2 = 0.138

0.000

0.050

0.100

0.150

0.200

0.250

0 100 200 300 400

Fst

Geographic Distance (km)
231

5.3 BLACK CORAL GENETICS AND CONNECTIVITY

5.3.1 Introduction

The scale over which coral communities in general, and deep-sea communities in particular, should 

be managed is not readily apparent. Many marine organisms have planktonic larvae and it is not 

clear how far these larvae travel. Do they connect sites, regions or even entire ocean basins? 

Estimates of connectivity through larval exchange are needed to understand the scale at which 

populations are regulated, estimate the risk of extinction of locally devastated populations and 

understand the nature of barriers to dispersal in the ocean (e.g. depth, currents). In order to answer 

these questions, we utilize a combination of modern molecular and classical cladistic approaches 

to determine relations among communities in the GoM. This requires a nested analysis of first 

determining species status to exclude cryptic species, followed by a sub-species level analysis of 

population structure and geneflow.

Here, we focus on the dispersal capabilities of the black coral, Leiopathes glaberrima in the GoM.

Three biogeographic regions have been described for the GoM based on species distribution and 

food availability (Cairns, Figure 5-19). Most of the deep GoM is soft sediment, however hard

grounds occur as a result of authigenic carbonate deposition associated with current or historical 

hydrocarbon seepage. When the hard grounds occur in areas where hydrological conditions are 

appropriate for sediment removal, gas exchange and food delivery, colonial corals may occur. 

Previous connectivity studies of organisms associated with these hard grounds, including the deep 

sea scleractinian coral Lophelia pertusa, and hydrocarbon seep vestimentiferan worms 

Lamellibranchia luymesi and Seepiophila jonesi, and the seep mussel Bathymodiolus childressi 

suggested panmixia among sites within the northern GoM (Carney, et al. 2006; McMullinet al. 

2010; Morrisonet al. 2011). However, no study has addressed population connectivity in any of 

the approximately 30 species of black corals (antipatharians) found in the GoM (Opresko 2009). 

L. glaberrima is one of the most abundant corals on carbonate outcrops between about 200 and 

600 m (Brooke and Schroeder 2007) in the GoM and occurs world-wide including the North 

Pacific (Hawaiian islands), Mediterranean Sea, the Caribbean and Western and Eastern Atlantic 

(Cairns and Opresko 1993). It is a foundation species whose three-dimensional structure provides 

habitat for many cold-water reef organisms (Brooke and Schroeder 2007). Multiple color morphs 

of L. glaberrima co-occur in the GoM and the Atlantic and polyp size also varies within colonies 

(D. Opresko, per. comm.) but their species status is unclear (Opresko 2009). Many corals have 

the capacity to change colony shape, form and color in response to the environment, but these 

morphological differences are sometimes attributable to genetic variation (Todd 2008). In the 

antipatharia, differentiation at the species level is complicated by morphological simplicity and 

high plasticity (Opresko 2009). According to Opresko (2009), collections of black corals from the 

GoM suggest the possibility of un-described species of Leiopathes, which are indistinguishable by 

classic taxonomy. Therefore, in order to perform population genetics, analyses the species status 

of the color morphotypes had to be determined. 
232

Figure 5-19. Sampling sites for Leiopathes glabberima (inset) in the GoM. 

GB = Garden Banks, GC = Green Canyon, VK = Vioska Knoll, 

WFS = West Florida Slope. GB and GC are in biogeographic 

region I, VK is in biogeographic region II and WFS is within 

biogeographic region III (Cairns and Opresko 1993). Map from 

Google Earth.

In marine benthic organisms, population subdivision is influenced by timing of reproduction, 

larval duration, circulation patterns and availability of substrate (Miller 1998; Palumbi 2003; 

Morrison, Ross et al. 2011). The life history of Leiopathes glaberrima is unknown, but studies in 

other antipatharians suggest annual reproduction, with larvae that are negatively buoyant, nonfeeding and short lived (10 days) (Miller 1997; Miller 1998). Asexual larvae have also been 

observed (Miller 1997). Therefore, the lack of population structure in L. pertusa with relatively 

long larval duration or of the vestimentiferans with long-lived and positively buoyant larvae, might 

not be representative of the population structure of L. glaberrima. 

Here, we used mitochondrial and nuclear markers to test the hypothesis that color morphs of 

Leiopathes glaberrima constitute one biological species. We then developed ten novel 

microsatellite loci for L. glaberrima and applied them to samples from the GoM to determine 

population genetic structure, reproductive characteristics and gene flow patterns in this important 

foundation species. 

Molecular markers are still sparse for the Cnidaria. Mitochondrial markers have low levels of 

variation in some cnidarian groups making species identification difficult (Hellberg 2006), and 

hence microsatellite markers have been the marker of choice for population genetic studies. Yet, 

previous work had indicated that in corals unusual microsatellite motives might be common 
233

(Baums et al. 2005). To facilitate development of microsatellite markers in the Cnidaria in general 

and generate markers for L. glaberrima, we studied characteristics of microsatellite markers in 9 

species of Cnidaria and have submitted this work for publication (Appendix D-3).

5.3.2 Methods

5.3.2.1 Sample Collection, DNA Extraction, Sequencing and Genotyping

222 samples from different morphotypes of Leiopathes glaberrima from five sites in the GoM

(Figure 5-19) were collected by the ROV Jason II during the TDI-Brooks R/V Ron Brown/Jason

II Lophelia II expedition (August 6 to September 12, 2009 and October 15 to November 1, 2010), 

and by the USGS R/V Seward Johnson/JSL cruise (September 16 to 23, 2009 and Sept 22 to 

October 2, 2010). Collection depths were between 248 m and 674 m depths. The samples show a 

range of color patterns from white to red (Table 5-7). For each sample, tissue was frozen at -80°C, 

preserved in 70% ethanol and in RNA later. Images of the colonies were taken during the 

collection; additional images were taken in the wet laboratory on board of the ship. Depth and 

locations were obtained from the ROVs logs. 

Table 5-7.

Leiopathes glaberrima samples from the GoM. Two lineages (L1 and L2) were identified with 

microsatellite (Msat) loci. The total number of samples (N) and number of distinct multilocus 

genotypes, Ng, as identified by microsatellite genotyping is indicated. Samples were categorized 

by sampling depth (in 50 m intervals) and colony color when available

Msat Depth (m) Color

Sites N L1 L 2 200-

250

251-

300

301-

350

351-

400

401-

450

451-

500

501-

550 orange pink red white yellow

GB299 30 28 . . . 11 17 . . . 1 3 . 15 1

GC140 23 20 2 8 15 . . . . . 4 9 . 7 .

VK826 75 8 46 . . . . 4 55 3 14 13 19 9 4

VK862 2 . . . . . 1 . . . 1 . . . .

VK906 74 5 29 . . 1 9 18 . . 4 4 10 10

WFL 

Slope 6 . 1 . . . 1 2 . 3 3 . . 1 .

N 210 64 136 8 15 12 28 24 55 6 27 29 29 42 5

Ng 150 61 79 . . . . . . . . . . . .

Ng/N 0.7

1

0.9

5

0.5

8

. . . . . . . . . . . .

To test the species identity of the samples, different color morphotypes of L. glaberrima from 

five sites (

Table 5-8) were compared using Leiopathes-specific primers to three mitochondrial genes: COI, 

ND5 and Trp (partial TrnW-ITS-NADH) using published methods (Brugler and France 2007; 

Sinniger and Pawlowski 2009). Amplification products were treated with Exo-Sap reaction (GE 

Healthcare) and sequenced at the Genomic Core Facility at University Park. 
234

Table 5-8.

Samples (N) of Leiopathes glaberrima were sequenced at three mitochondrial loci (COI, ND and 

TRP) from five sites in the GoM

N

Marker GB299 GC140 VK826 VK906 WFLSlope Total

COI 1 27 12 40

ND 1 1 25 25 3 55

TRP 2 1 22 16 1 42

Total 3 3 74 53 4 137

Microsatellites (Simple Sequence Repeats SSRs) for population connectivity analyses of L. 

glaberrima were designed using sequence data from a single plate of 454 sequencing. Contigs 

and singletons were imported to the Tandem Repeat Finder (TRF) database and processed using 

the default values of Match: 2, Mismatch: 7, Indels: 7 as alignment parameters (Benson 1999). 

Sequences were annotated for perfect motifs and flanking regions of at least 100 bases using 

Geneious (Drummond, Ashton et al. 2010) and imported to Primer 3 for primer design (Rozen and 

Skaletsky 2000). Primers were realigned to the sequences with Codon Code Aligner (CodonCode 

Corporation, Dedham, Massachusetts). Candidate loci were tested for polymorphism and reliable 

amplification on samples from the most geographically distant sites in the GoM (VK906, GB535 

and West Florida Slope) resulting in polymorphic 10 loci (Table 5-9). 210 samples yielded 

complete multilocus genotypes for all 10 loci (Table 5-8).

5.3.2.2 Phylogenetic and Population Genetic Analyses

Sequences were edited and aligned using Codon Code Aligner (CodonCode Corporation, Dedham, 

Massachusetts). Bayesian phylogenetic trees were constructed in MrBayes (Ronquist and 

Huelsenbeck 2003), the parameters used were 4 heated chains (temp= 0.2) with 1100000 MCMC 

generations and random seed of 1063, sample frequency was 200 generations. The burn in for the 

consensus 50% majority rule tree was 500. 

Population genetic analyses were performed using the program GenAlEx vers 6.5 (Peakall and 

Smouse 2006). First, exact matches at all loci were identified. Samples that shared the exact 

multilocus genotype (MLG) at all 10 loci were considered to be clonemates of the same genet. 

GenAlEx estimated the probability of identity (or the probability that two samples share the same 

multilocus genotype even though they are not clones) as 10-7across populations when using all 10 

loci. Subsequent population genetic analyses were performed on the unique MLGs only. Loci were 

then tested for adherence to Hardy-Weinberg Equilibrium when considering all unique MLGs and 

when analyzing microsatellite lineage 1 and 2 (see below) separately. Principal Coordinate 

analysis was performed on a pairwise genetic distance matrix (Fst) among all samples in GenAlEx. 

The program Structure (Pritchard, Stephens et al. 2000) was further used to detect the number of 

genetically distinct clusters, K, in the dataset and was run with 106steps. 10% of the MCMC chain 

was discarded as burnin and each K was repeated three times. We assumed admixture and did not 

specify a location prior as we suspected the presence of multiple lineages per location. Structure 

results were analyzed with the program Structure Harvester (Earl and vonHoldt 2012) to find the 
235

most likely number of population, K. Indeed, Structure identified the presence of two co-occurring 

lineages. 

Table 5-9. 

Microsatellite loci developed for L. glaberrima. The ten microsatellite loci developed for L. 

glaberrima were amplified in two multiplexes (plex 1-2) and three singleplex reaction. Given is 

the locus name, primer sequences, repeat type followed by the number of repeats and the size 

range of the alleles amplified in base pairs (bp). Annealing temperature was 54oC for Multiplex 1 

and BC19, 57oC for Multiplex 2, and 55oC for singleplexes 34 and 36. Forward primers were 

fluorescently labeled with one of four dyes (6FAM, VIC, PET or NED)

Locus Primer sequence (5'-3') STR motif Size (bp) Plex

BC1 F: PET-TAG TAC CCT CGC AGC AGG GTG (ACT)6 182-185 2

R: GAA TTC CGC TCG TCC TCC A

BC5 F: 6FAM-TGA AGA GTG AGC ACT CGT T (TTG)8.6 193-235 2

R: CAG TAT GTC CGC GTC ATC TT

BC8 F: NED-CAC AGT AAG CTG ACC GTC TGC (TTA)11 119-147 2

R: TAC CGT ATG CCC ACG AAG AGC

BC11 F: PET-GAG ACA TGA CTT TCC AGA TCC GCT (AAC)14 Y (TGTAA)4 123-183 1

R: CGT AAA TCA GCA CAC ATT TCC GGT 

BC22 F: NED- GCA ACA GAG AGC TTG GTT CAA (GTT)10 142-163 1

R: CTT CCT GTC CCA ACA CCC T 

BC43 F: VIC-ATC CTC TGT GGT GTA TGT T (CCA)5 141-147 1

R: AGT GAT CTC CCA TTC GAC C

BC67 F: 6FAM-TCC CTT TCA AGA TCC GTA (ATT)10 133-172 1

R: CGA CTA CAA TTC GAT CAA CA 

BC19 F: 6FAM-GCC AAT ATT GCT GCG GTT AC (GTTGGC)10.5 198-309 single

R: AAG AGA CAG GTC CGG TTG AA

BC34 F: T1-GGC TAG GAA AGG TTA GTG GCC ACA TGT CGT 

CCT GGA TAC G

(AACAAG)9 168-204 single

R: GCC TAA CTT TTA CTT TAT TTA TTG CAT

BC36 F: T3-ACC AAC CTA GGA AAC ACA GGA GCC CTG AAG 

GAT CAG AGA

(ACA)4 ATAG (TAA)9 174-207 single

R: AAA AGC ATC TAC GGG TGG TG

5.3.3 Results

Mitochondrial markers have low levels of variation in some cnidarian groups making species 

identification difficult (Hellberg 2006). This was observed in our data as two of the three markers

used (COI and ND5 fragments) had no resolution to distinguish between the samples of L. 

glaberrima from throughout the GoM (Table 5-7, Figure 5-20). In contrast, two lineages of L. 

glaberrima were recovered from Trp sequencing, but those lineages were unrelated to color morph 

(white, red and orange were mixed within both groups) (Figure 5-21). Other the Trp clades were 

unrelated to geography as samples from VK906 (n = 16) and VK826 (n = 22) were intermixed 

(Figure 5-21). The distinction between the two lineages was due to a single amino acid change. 

More genes are needed to determine if the two lineages are distinct enough to be considered 2 
236

species. To accomplish this, we developed and employed highly polymorphic microsatellite 

markers. 

Microsatellite loci amplified reliably and had on average 6.28 (+/- 0.53 Standard error [SE]) alleles 

per locus (Figure 5-22). Expected heterozygosity ranged from 0.26 to 0.90 (average = 0.61 +/-

0.03 SE). Probability of identity ranged from 2.8 * 10-3to 1 * 10-9per population when considering 

all loci indicating high power to distinguish between asexually produced individuals and those that 

are closely related (Figure 5-22). When analyzing only unique multi-locus genotypes (MLGs),

departures from Hardy-Weinberg equilibrium were significant in 23 out of 50 comparisons, mostly 

involving the two VK populations that harbor both microsatellite lineages (see below). When 

analyzing the two lineages separately, only 2 out of 38 tests and were significant for L1 (Figure 5-

22). Ho ever, half of the 34 tests in L2 remained significant (Figure 5-21).

Figure 5-20. Bayesian phylogenies of two mitochondrial markers COI (A, 740bp; GenBank 

Accession numbers: KF013048 - KF013088) and ND5 (B, 660 bp, GenBank 

Accession numbers: KF012993 - KF013047). There was very little sequences 

diversity in L. glaberrima samples from throughout the GoM resulting in star-shaped 

phylogenies.

Structure (Figure 5-23) and principal coordinate analysis ( Figure 5-24) indicated the presence of 

two divergent lineages in the dataset. GC140, GB299 and WFS each were dominated by lineage 1 

whereas VK906, the deepest of the sites, was dominated by lineage 2. VK826 harbored both 

lineages and 10 samples showed evidence of hybridization between them (assignment probability 

of <0.8). The most parsimonious explanation for this co-occurrence is the presence of cryptic 

species. And while the lineages do not correspond with color or depth (Figure 5-25); they do 

occupy different areas at VK826, the site where both occur (Figure 5-26). Lineage 1 is mostly 

restricted to the northern edge of the site (Figure 5-26). New datasets were created, each containing 

MLGs with >0.8 probability of belonging to one of the two lineages (Lineage 1: n = 61, Lineage 
237

2: N = 78, unassigned N: 10). When analyzing each lineage separately, geographic differentiation 

was small and significant only for lineage 2 (Table 5-11), perhaps due to the now small sample 

sizes.

Table 5-10

Leiopathes glaberrima microsatellite loci. Given are: N = number of samples genotyped at that 

locus, Na = No. of Different Alleles, Ho = Observed Heterozygosity, He = Expected 

Heterozygosity, Ht = Total Expected Heterozygosity, F = Fixation Index. Fis = (Mean He -

Mean Ho) / Mean He, Fit = (Ht - Mean Ho) / Ht, Fst = (Ht - Mean He) / Ht. SE = standard error. 

Calculated by GenAlEx vers. 6.5

BC1 BC5 BC8 BC11 BC19 BC22 BC34 BC36 BC43 BC67 Total

N Mean 29.60 29.20 29.40 29.60 29.40 29.80 29.80 29.20 29.60 29.60 29.52

SE 9.13 8.74 8.74 9.10 8.91 9.09 9.09 8.74 8.91 9.22 2.56

Na Mean 2.00 6.00 5.80 11.60 12.20 4.20 5.80 4.60 2.40 8.20 6.28

SE 0.00 0.71 0.58 1.33 1.07 0.73 0.80 0.93 0.24 1.24 0.53

Ho Mean 0.29 0.76 0.49 0.87 0.90 0.26 0.57 0.56 0.30 0.69 0.57

SE 0.09 0.09 0.07 0.04 0.03 0.04 0.08 0.03 0.11 0.10 0.04

He Mean 0.23 0.66 0.69 0.87 0.87 0.38 0.62 0.62 0.34 0.77 0.61

SE 0.06 0.02 0.02 0.01 0.01 0.07 0.04 0.06 0.08 0.06 0.03

F Mean -0.19 -0.15 0.29 -0.01 -0.04 0.27 0.09 0.05 0.22 0.12 0.07

SE 0.07 0.11 0.10 0.06 0.04 0.10 0.09 0.13 0.19 0.10 0.04

Fis -0.26 -0.16 0.29 0.00 -0.04 0.32 0.08 0.10 0.10 0.10 0.05

SE 0.06

Fit -0.17 -0.13 0.34 0.04 0.00 0.56 0.14 0.22 0.38 0.20 0.16

SE 0.07

Fst 0.07 0.02 0.06 0.04 0.04 0.36 0.07 0.13 0.31 0.11 0.12

SE 0.04

Table 5-11.

Analysis of molecular variance (AMOVA) among sites and lineages (L1 and L2). Within 

individual analysis was suppressed and significance evaluated based on 999 permutations across 

the whole dataset. % = percent of the estimated total variance. Df = de

All Source df SS MS % Fst Fst max F'st

Among Pops 4 103.49 25.87 12% 0.12** 0.38 0.32

Within Pops 293 915.98 3.13 88%

Total 297 1019.48 100%

L1 Among Pops 3 10.33 3.44 1% 0.01 0.40 0.01

Within Pops 118 352.11 2.98 99%

Total 121 362.44 100%

L2 Among Pops 1 10.84 10.84 4% 0.04** 0.41 0.09

Within Pops 148 436.00 2.95 96%

Total 149 446.84 100%
238

Figure 5-21. Phylogeny (Bayesian Inference) of a portion of the mitochondrial TRP gene (730 

bp GenBank Accession numbers: KF013089 - KF013130). Two lineages within L. 

glaberrima from the GoM are revealed by the TRP gene, distinct by one amino acid 

change. Numbers represent posterior probabilities. Note that the two lineages are 

unrelated to color of the colonies (Red labels indicate red colonies, orange labels 

orange colonies, blue labels white colonies and black labels are colonies with no 

associated color information), sampling site (VK906, VK826) or microsatellite lineage 

designation (see next section).
239

Of the 210 samples genotyped, 20 had MLGs that occurred more than once in the dataset. The 

ratio of the number of unique MLGs over the number of samples was 0.95 in Lineage 1 (Ng = 61, 

N = 64) and 0.57 in Lineage 2 (Ng = 78, N = 136). Most of the potential clones were found in 

lineage 2 at VK906, where the two largest genets had 15 and 21 members (Figure 5-27). In 

contrast, the largest number of clonemates per genet was just 3 in lineage 1 (GB299). Studies are 

still needed to determine the mode of clonal reproduction (ameiotic larval production, 

fragmentation or polyp bail-out). However, so far clones appear to be restricted to specific sites as 

no MLGs were shared between sites. The largest distance between clonemates was 610 m in 

lineage 2 (Table 5-12, only colonies were included in this table for which geographical location 

was recorded with accuracy of < 10 m). Clonemates of the same genets sometimes (n = 6 or 5%) 

showed different shades of orange to red but not white and red (Figure 5-28). 

Figure 5-22. Mean F values for microsatellite loci. Mean F values were not 

significantly different from zero for most loci (BC 1 – BC 67) in lineage 

1 (L1) but in lineage 2 (L2), F-values consistently deviated from 

expectations. Given are means across loci and their standard errors.

Figure 5-23. Population genetic analysis of 148 L. glaberrima genotypes from the GoM. The 

STRUCTURE plot shows the probability of membership of each of the samples in 

K=2 clusters (the optimal number of clusters for this dataset). VK826 harbors colonies 

with ancestry in both lineages (hybrids). VK862 excluded (n=2).
240

Figure 5-24. Principal coordinates analysis of 148 L. glaberrima genotypes from the GoM. For 

comparison with Fig 3, the two lineages identified via STRUCTURE analysis are 

indicated here by the blue and red circle. Shown are the first two axes, explaining 

46.05% and 13.27% of the variation, respectively. VK862 excluded (n=2).

Table 5-12.

Spatial spread of genets (m) for collections with good navigational data. Navigational accuracy 

within a single cruise is generally about +/- 5 m at this depth using USBL alone and about twice 

that (+/- 10 m) when data from independent visits are combined. In many cases distances 

between corals were determined using doppler velocity navigation streams during a single dive 

and this can result in paired distance estimates accurate to about 0.5 m. N = number of ramets per 

genet. SD = standard deviation, * only a single clone pair was identified.

Site Clone ID Mean (m) SD Max (m) N Msat Lineage

VK826

BC1054 104 84 155 3 2

BC1055 72 40 108 3 2

BC1064 2* 2 2 2

BC1073 2* 2 2 2

BC1122 2* 33 2 2

Mean (SD)* 43 (45) 60 (69)

VK906

BC1093 60 32 131 19 2

BC1094 37 21 75 13 2

BC1098 65 35 106 4 2

BC1110 80 61 117 3 2

BC1117 610* 610 2 2

BC1099 144* 144 2 2

BC1097 45* 45 2 2

BC1096 42* 42 2 2

Mean (SD)* 135 (195) 159 (186)
241

Figure 5-25. Principal coordinates analysis of 148 L. glaberrima genotypes from the GoM. No 

structuring by color of the colony (A) or by depth (B) is evident. Shown are the first 

two axes, explaining 46% and 13% of the variation, respectively. Depth is in 50 m

increments. Samples sizes per depth given in parentheses. uk = color unknown.
242

Figure 5-26. Geographical distribution of Leiopathes glaberrima lineages. Vioska Knoll 826 

(A) harbors two lineages of L glaberrima (Msat Lineage 1, 2). Lineage 1 is mostly 

restricted to the northern edge of the site. Lineage 2 and hybrids between lineages 1 

and 2 (designated as Lineage 3) occur throughout the site. Permanent markers 

(Mosaic N – Q) are indicated. Vioska Knoll 906 (B) harbors only one lineage of L. 

glaberrima (Msat 2). Two meter contours created by Miles Saunders from R/V Falkor

Shipboard Multibeam 11/2012. Maps oriented towards North.

Figure 5-27. Geographic distribution of clone mates of Leiopathes glaberrima at VK826 and 

VK906. Msat lineage 2 of Leiopathes glaberrima frequently reproduces asexually at 

Vioska Knoll 826 (A) and VK906 (B) while lineage 1 does so rarely. Same fill 
243

indicates that two colonies are clonemates. Black fill indicates colonies with unique 

genotype, represented only once at the site. No clones were shared between sites. Two 

meter contours created by Miles Saunders from R/V Falkor Shipboard Multibeam 

11/2012. Map oriented towards North.

Figure 5-28. Geographic distribution of Leiopathes glaberrima color morphs in VK826 and 

VK906. A) VK826, B) VK906. Two meter contours created by Miles Saunders from 

R/V Falkor Shipboard Multibeam 11/2012. Map oriented towards North.

5.3.4 Discussion

The black coral, Leiopathes glaberrima, is an important foundation species in the deep GoM and 

elsewhere. Here, we developed new microsatellite loci and applied them to samples from three 

biogeographic regions in the GoM. We discovered the presence of two lineages. Lineage 1 is widespread throughout the Gulf, dominating Green Canyon, GB and the West Florida Shelf site. One 

Vioska Knoll site, VK906, almost exclusively harbors lineage 2. VK826, 25 nm from VK906, 

contains both lineages and a few of the colonies appear to be of mixed ancestry indicating 

hybridization between the lineages at this site. It is unclear at this point what taxonomic status the 

lineages have as neither color pattern nor mitochondrial DNA patterns coincide with the lineages 

defined via microsatellite genotyping. Nevertheless, reproductive patterns appear to differ between 

the lineages. Lineage 2 has much higher levels of clonal reproduction than Lineage 1 (Table 5-12). 

However, because sampling effort was not constant among sites, this finding will have to be 

confirmed in future studies. VK906 is a much smaller site than VK826 and thus samples were 

taken closer together, increasing the chance of sampling clonemates. When analyzed separately, 

lineage 1 does not show further geographic differentiation among sites in the GoM, similar to 

findings for L. pertusa (Morrison, Ross et al. 2011). Increased sample sizes and geographic 

coverage might discover more subtle signs of population structure in the future. Interestingly, the 
244

two lineages also differed in their adherence to Hardy-Weinberg equilibrium assumptions (Figure 

5-22). 

The wider spread lineage 1 conforms to the expectations of an outbred species (once clones are 

removed from the dataset). In contrast, lineage 2 is highly inbred. Recall that lineage 2 dominated 

at VK906, where samples came from two isolated mounds, each about 200 m in diameter rising 

40 m from the ocean floor. The top of each mound is densely settled with corals, including L. 

pertusa and L. glaberrima. The combination of limited habitat and relative isolation of this site 

might explain the increased inbreeding found in lineage 2. 

Repeated multilocus genotypes were only found within sites and were never shared among sites 

(largest distance between two clonemates was 611 m, Table 5-12) indicating that asexual 

reproduction is a local process. The two principal modes of asexual reproduction in corals are 

fragmentation and production of asexual (ameiotic) larvae. Often, planktonic larvae have a broader 

dispersal potential than large fragments, but not so in black corals, which are thought to have shortlived, crawl away larvae (Miller 1998; Wagner et al 2011, Waller and Tyler 2005). In addition, we 

have at times observed that polyps will “bail-out” (Sammarco 1982), dropping from the skeleton 

of the colonies to the floor of aquaria when stressed, which may provide yet another form of 

asexual reproduction. We cannot at present distinguish between these potential modes of asexual 

reproduction, and this will not be an easy task due to the cost and difficulty of working with deep 

sea species. 

Cryptic species are common in the marine environment (Knowlton 1993). Recent advances in 

genetic tools have led to the discovery of several cryptic lineages within morphologically similar 

collections of corals (Pinzón, Sampayo et al. 2013; Boulay, Hellberg et al. 2014). Mitochondrial 

DNA has poor resolution power in the Cnidaria (Shearer, Van Oppen et al. 2002; Hellberg 2006), 

and nuclear ITS markers are multi-copy, which complicates their interpretation (Ridgway 2002; 

Álvarez and Wendel 2003; Forsman, Hunter et al. 2006). Therefore, microsatellite markers have 

become increasingly popular for detection of cryptic lineage (Souter 2010; Nakajima, Nishikawa 

et al. 2012). Similar to the findings for L. glaberrima, the wide-spread shallow-water reef builder 

Porites lobata, actually consists of two morphologically similar species in the Eastern Pacific 

(Boulay, Hellberg et al. 2014). The two Porites species differ in the amount of asexual 

reproduction. P. evermanni, the species with higher frequency of asexual reproduction is able to 

persist in more marginal environments, perhaps because locally well adapted genotypes do not 

require the presence of a sexual partner to proliferate and dominate local communities (Boulay, 

Hellberg et al. 2014). If true for the two lineages of L. glaberrima, they might occupy different 

niches in the deep GoM. Corroborating evidence for this interpretation comes from the distribution 

of L. glaberrima at VK826 where lineage 1 appears mostly restricted to the northern edge of the 

site (Figure 5-26).

Because of the discovery of cryptic lineages within the dataset, sample sizes and geographic 

coverage were not sufficient to test dispersal and gene flow hypotheses rigorously for the two 

lineages. Additional sampling will be necessary to accomplish that goal. However, our preliminary 

evidence indicates that lineage 1 is wide-spread with high connectivity among populations whereas 

lineage 2 is restricted and shows limited gene flow even between the nearby sites of VK826 and 

VK906. Bio-physical modeling of dispersal pathways would allow us to test the hypothesis that 
245

the isolation and shape of VK906 contributes to increased self-recruitment at that site (Baums, 

Paris et al. 2006). Additionally, the data suggests that the two lineages differ in their sexual and 

asexual reproductive strategies. This hypothesis could be tested with histological investigations of 

the two lineages.

It is important to note that because of the restricted distribution and high amount of inbreeding 

observed, lineage 2 deserves particular attention with respect to management and oversight of deep 

living corals in the GoM.
246

6 TROPHIC STUDIES

6.1 BACKGROUND

Octocorals (soft corals) in the GoM add heterogeneity to the seafloor and provide important habitat 

to other species (Buhl-Moretensen et al. 2010), but the nutritional sources for these corals, 

especially those occurring on the deeper portion of the continental slope below 1000 m are not 

well understood. Previous studies have noted that deepwater corals often occur in areas of past or 

current hydrocarbon seepage and some have suggested a nutritional link between the corals and 

local chemoautotrophic primary production from the seep environment. In the Lophelia I project, 

Becker et al. (2009) analyzed the stable isotope compositions of the reef-forming coral Lophelia

pertusa and its associated fauna, as well as a few samples of octocroals from deeper sites, and 

found no evidence of significant incorporation of seep-derived nutrition by deepwater corals. In 

the Lophelia II project, we expanded our sampling of deepwater corals, especially octocorals 

occurring at deeper sites, to discern spatial and interspecific patterns in coral tissue stable isotope 

contents and infer nutritional sources. 

Some octocorals, especially the genera Callogorgia and Paramuicea, may form symbiotic 

relationships with ophiuroid brittle stars (Figure 6-1). Researchers that have observed similar 

associations in other deep sea environments have suggested that the brittle stars are suspension 

feeders and use the structure of the gorgonians to escape the benthic boundary layer and increase 

their contact with food particles carried by bottom currents or resuspended from the sediment 

(Buhl-Moretensen et al. 2010) or that they consume a product of the corals such as mucus or feces 

(Emson and Woodley 1987). Tissue was sampled from 37 octocoral and ophiuroid pairs to 

examine whether there is evidence of a trophic relationship between the corals and their epizoic 

ophiuroids.

Tissues were also sampled for stable isotope analysis from the associated macrofauna in two of 

the quantitative L. pertusa coral pot collections. In the Lophelia I project, L. pertusa was often 

observed growing intermixed with senescent seep tube worms, but these communities were not 

targeted for collection and stable isotope analysis to determine the importance of seep primary 

production to this community. This previous work showed seep-derived nutrition is not a 

requirement for the corals or their associated communities (Becker 2009), but it remains to be 

determined whether the animals associated with L. pertusa utilize this source when it is in very 

close proximity to the corals. One of the two coral pot collections used for stable isotope analysis 

targeted a community of intermixed L. pertusa and seep tube worms. 
247

Figure 6-1. Callogorgia americana and commensal ophiuroids.

6.2 METHODS

6.2.1 Sampling

Tissue samples for stable isotope analysis were obtained from corals and ophiuroids collected for 

genetic analyses into collection quivers and the biobox by removing coral tissue from the skeleton 

or, for ophiuroids, dissecting a piece of leg muscle tissue. Stable isotope samples were also taken 

from two of the coral pot collections that targeted Lophelia pertusa and its associated community. 

For these collections, up to three individuals of each species were sampled by dissecting a piece 

of muscle tissue from large animals or using whole individuals for smaller animals. The samples 

were rinsed with deionized water to remove any residual seawater and frozen at -70C.

6.2.2 Stable Isotope Analysis

Samples were dried at 60C, homogenized, and acidified with 5% (2 normal) phosphoric acid to 

remove inorganic carbonate. Samples were redried and subsamples were analyzed for stable 

carbon and nitrogen isotope compositions at the Stable Isotope Facility at the University of 

California, Davis, using an Integra elemental analyzer coupled with a PDZ Europa 20-20 isotope 

ratio mass spectrometer (Sercon Ltd., Cheshire, United Kingdom). Data are calibrated to National 

Institute of Standards and Technology (NIST) reference materials. 

Values are expressed using δ (delta) notation and reported in units of permil (‰), where
248

δX = [(Rsample/Rstandard) – 1] × 103,

X = 13C or 15N and R = 13C/12C or 15N/14N.

Values are reported relative to Pee Dee Belemnite (PDB) for carbon and air N2 for nitrogen. 

Samples were sometimes too small to obtain the δ15N composition and only the 

13C is reported.

6.2.3 Statistical Analysis

Simple linear regression was used to test for a relationship between the 

13C values of corals and 

their commensal ophiuroids. For δ15N values, a nonparametric Spearman Rank correlation analysis 

was performed, because δ15N data were not normally distributed.

6.3 RESULTS

6.3.1 Interspecific and Spatial Variation in Coral Tissue Stable Isotope 

Compositions

The majority of the corals had tissue stable isotope δ13C values between -24‰ and -17‰ and δ15N 

values from 6‰ to 12‰ (Table 6-1, Figure 6-2). Callogorgia americana delta had the broadest 

range in stable isotope values (

13C = -33.3 to -20.2‰ and δ15N = 2.1‰ to 11.5‰). Higher δ15N 

values were found in one Paramuricea biscaya B1 individual (14.9‰) and some Callogorgia 

americana americana individuals (14.9‰, 15.3‰, 18.0‰) (Figure 6-2).
249

Table 6-1.

δ

13C and δ15N compositions for all soft corals sampled in this study

Coral taxon δ

13C δ15N Site Dive

Callogorgia americana americana -21.3 8.5 GB299 J2-530 361

Callogorgia americana americana -19.9 10.5 GB299 J2-530 358

Callogorgia americana americana -20.9 10.3 GB299 J2-530 358

Callogorgia americana americana -21.8 10.5 GB299 J2-530 359

Callogorgia americana americana -21.9 9.0 GB299 J2-530 360

Callogorgia americana americana -19.5 15.3 VK862 J2-535 352

Callogorgia americana americana -19.7 14.9 VK862 J2-535 352

Callogorgia americana americana -20.3 18.0 VK862 J2-535 357

Callogorgia americana delta -24.6 5.6 GC246 J2-528 845

Callogorgia americana delta -23.9 GC246 J2-528 845

Callogorgia americana delta -25.4 GC246 J2-528 847

Callogorgia americana delta -25.0 5.2 GC246 J2-528 848

Callogorgia americana delta -27.1 GC246 J2-528 846

Callogorgia americana delta -25.1 6.6 GC249 J2-533 778

Callogorgia americana delta -33.1 2.1 GC249 J2-533 789

Callogorgia americana delta -32.3 2.8 GC249 J2-533 790

Callogorgia americana delta -33.3 3.0 GC249 J2-533 790

Callogorgia americana delta -21.1 8.4 GC249 J2-533 790

Callogorgia americana delta -22.1 9.5 MC751 J2-536 442

Callogorgia americana delta -22.1 9.5 MC751 J2-536 442

Callogorgia americana delta -22.4 9.9 MC751 J2-536 441

Callogorgia americana delta -21.9 10.8 MC751 J2-536 443

Callogorgia americana delta -22.9 9.7 MC885 J2-527 627

Callogorgia americana delta -23.8 9.4 MC885 J2-527 631

Callogorgia americana delta -23.8 8.5 MC885 J2-527 630

Callogorgia americana delta -28.8 4.4 MC885 J2-527 625

Callogorgia americana delta -23.3 8.8 MC885 J2-527 631

Callogorgia americana delta -27.7 5.4 MC885 J2-527 625

Callogorgia americana delta -21.2 VK826 J2-540 543

Callogorgia americana delta -21.1 10.2 VK826 J2-540 543

Callogorgia americana delta -21.4 VK826 J2-540 543

Callogorgia americana delta -21.0 11.1 VK826 J2-540 541

Callogorgia americana delta -20.2 11.5 VK826 J2-540 541

Callogorgia americana delta -21.3 VK826 J2-540 540

Cup Coral -20.5 MC118 J2-538 887

Leiopathes -20.7 7.4 GB299 J2-530 NA

Leiopathes -20.6 8.2 GB299 J2-530 342

Leiopathes -21.0 9.2 GB299 J2-530 342

Leiopathes -21.0 9.3 GB299 J2-530 358

Leiopathes -20.5 9.2 GB299 J2-530 361

Leiopathes -19.3 9.8 VK906 J2-534 403

Leiopathes -19.6 10.6 VK906 J2-534 403

Leiopathes -20.8 9.9 VK906 J2-534 391

Leiopathes -19.5 9.3 VK906 J2-534 403

Leiopathes -19.0 9.7 VK906 J2-534 401

 Depth
250

Table 6-1. δ

13C and δ15N compositions for all soft corals sampled in this study (continued)

Coral taxon δ

13C δ15N Site Dive

Leiopathes sp. -19.9 9.6 VK906 J2-534 401

Leiopathes sp. -19.5 9.4 VK906 J2-534 409

Leiopathes sp. -19.6 10.1 VK906 J2-534 403

Leiopathes sp. -19.0 9.4 VK906 J2-534 403

Leiopathes sp. -19.1 9.9 VK906 J2-534 403

Leiopathes sp. -19.2 10.8 VK906 J2-534 402

Lophelia pertusa -19.5 10.3 MC751 J2-536 441

Lophelia pertusa -22.3 GC354 J2-529 526

Lophelia pertusa -19.6 8.7 GB535 J2-531 517

Lophelia pertusa -21.0 VK906 J2-534 403

Lophelia pertusa -19.3 10.8 VK906 J2-534 393

Lophelia pertusa -18.5 10.4 VK906 J2-534 401

Lophelia pertusa -18.2 10.6 VK906 J2-534 399

Lophelia pertusa -19.1 9.9 VK906 J2-534 402

Lophelia pertusa -19.9 10.8 MC751 J2-536 441

Lophelia pertusa -19.2 10.4 MC751 J2-536 440

Lophelia pertusa -18.4 10.4 MC751 J2-536 439

Lophelia pertusa -18.0 9.6 MC751 J2-536 441

Lophelia pertusa -20.0 9.8 MC794 Gulfoil J2-537 532

Madrepora -25.5 MC338 J2-541 1373

Muriceides cf. hirta 1a -18.9 11.0 VK906 J2-534 432

Octocoral -16.6 10.8 MC751 J2-536 440

Octocoral -23.0 5.5 MC751 J2-536 440

Paramuricea biscaya B1 -20.8 10.2 DC673 J2-539 2160

Paramuricea biscaya B1 -18.3 11.3 DC673 J2-539 2203

Paramuricea biscaya B1 -18.5 10.9 DC673 J2-539 2398

Paramuricea biscaya B1 -21.1 14.9 DC673 J2-539 2207

Paramuricea biscaya B1 -20.0 11.6 DC673 J2-539 2313

Paramuricea biscaya B2 -20.9 10.6 DC673 J2-539 2400

Paramuricea sp. -19.1 9.6 MC338 J2-541 1373

Paramuricea sp. B3 -22.6 7.1 GC246 J2-528 845

Paramuricea sp. B3 -20.0 9.7 MC118 J2-538 885

Paramuricea sp. B3 -20.0 10.7 MC118 J2-538 889

Paramuricea sp. B3 -19.4 8.3 MC118 J2-538 884

Paramuricea sp. B3 -20.6 9.3 MC118 J2-538 887

Paramuricea sp. B3 -21.5 10.5 MC118 J2-538 884

Paramuricea sp. E -20.0 9.7 GB299 J2-530 342

Paramuricea sp. E -20.5 9.2 GB299 J2-530 361

Paramuricea sp. E -20.5 9.2 GB299 J2-530 361

Paramuricea sp. E -20.1 9.0 GB299 J2-530 361

Paramuricea sp. E -20.2 10.3 MC751 J2-536 441

Paramuricea sp. E -20.5 6.6 MC751 J2-536 441

Paramuricea sp. E -20.7 11.9 MC751 J2-536 440

Paramuricea sp. E -20.7 10.2 MC751 J2-536 440

Paramuricea sp. E -19.3 10.0 MC751 J2-536 441

Swiftia exserta -20.9 6.6 MC751 J2-536 440

 Depth
251

Figure 6-2. δ

15N vs. 13C for all soft corals sampled for stable isotope analysis.

The 

13C and δ15N values of Paramuricea sp. E and Leiopathes sp. did not differ substantially 

between sites (Figure 6-3c,d). Callogorgia americana americana δ

15N values differed between 

VK862 (δ15N = 14.9 to 18.0‰) and GB299 (δ15N = 8.5 to 10.5‰, Figure 6-3c), while δ

13C values 

were similar between VK862 (-19.5 to -20.3‰) and GB299 (-19.9‰ to -21.9‰, Figure 6-3c). 

Stable isotope values of Callogorgia americana delta did not differ between VK826 and MC751 

(Figure 6-3a). The stable isotope values of samples from GC246 clustered together and were 

markedly different from the 

13C and δ15N compositions of samples from MC751 and VK826 

(Figure 6-3a). There was a large range of both δ13C and δ15N values in Callogorgia americana 

delta sampled from GC249 (

13C = -33.3 to -21.1‰; δ15N = 2.1 to 8.4‰: Figure 6-3a) and MC885 

(

13C = -28.8 to -22.9‰; δ15N = 4.4 to 9.7‰ δ15N, Figure 6-3).
252

Figure 6-3. δ

15N vs. δ13C of (A) Calligorgia americana delta, (B) Callogorgia 

americana americana, (C) Paramuricea sp. E, and (D) Leiopathes sp., 

with difference symbols representing different sampling sites.

6.3.2 Corals with Paired Commensal Ophiuroids

There was a significant linear relationship between tissue 

13C composition of corals and the 

commensal ophiuroids that were associated with them (simple linear regression: R2 = 0.51, p < 

0.0001; Figure 6-4a), but the relationship was not significant for δ15N (Spearman rank correlation 

for non-normally distributed data: p=0.076; Figure 6-4b). Qualitatively, the δ15N values of 

ophiuroids and their paired coral appear similar, except for the C. americana americana

individuals with anomalously high δ15N values, whose paired ophiuroids had tissue δ15N values 

within the lower end of the ophiuroid δ15N range ( Figure 6-4b, Figure 6-5b). 
253

Table 6-2.

δ

13C and δ15N values of octocorals and their epizoic ophiuroids (oph.). Where more than one 

ophiuroid was present on the same coral, the coral stable isotope data are repeated on a separate 

line

Coral taxon Paired oph. taxon Coral Oph. Coral Oph. Site Dive

Callogorgia americana americana Asteroschema sp. 1 -21.3 -16.4 8.5 9.4 GB299 J2-530 361

Callogorgia americana americana Asteroschema sp. 1 -19.9 -16.8 10.5 10.2 GB299 J2-530 358

Callogorgia americana americana Asteroschema sp. 1 -20.9 -16.0 10.3 11.4 GB299 J2-530 358

Callogorgia americana americana Asteroschema sp. 1 -19.5 -16.7 15.3 8.4 VK862 J2-535 352

Callogorgia americana americana Asteroschema sp. 1 -19.7 -16.7 14.9 8.4 VK862 J2-535 352

Callogorgia americana americana Asteroschema sp. 1 -20.3 -16.6 18.0 6.3 VK862 J2-535 357

Callogorgia americana delta Asteroschema sp. 1 -27.1 -24.6 -- 5.6 GC246 J2-528 846

Callogorgia americana delta Asteroschema sp. 1 -25.4 -20.5 -- 8.3 GC246 J2-528 847

Callogorgia americana delta Asteroschema sp. 1 -25.0 -20.6 5.2 -- GC246 J2-528 848

Callogorgia americana delta Asteroschema sp. 1 -23.9 -21.1 -- 8.7 GC246 J2-528 845

Callogorgia americana delta Asteroschema sp. 1 -24.6 -20.2 5.6 7.8 GC246 J2-528 845

Callogorgia americana delta Asteroschema sp. 1 -21.1 -22.9 8.4 5.8 GC249 J2-533 790

Callogorgia americana delta Asteroschema sp. 1 -21.9 -19.1 10.8 11.0 MC751 J2-536 443

Callogorgia americana delta Asteroschema sp. 1 -22.1 -16.9 9.5 11.2 MC751 J2-536 442

Callogorgia americana delta Asteroschema sp. 1 -22.1 -16.9 9.5 11.2 MC751 J2-536 442

Callogorgia americana delta Asteroschema sp. 1 -22.4 -18.0 9.9 9.1 MC751 J2-536 441

Callogorgia americana delta Asteroschema sp. 1 -22.9 -18.7 9.7 10.4 MC885 J2-527 627

Callogorgia americana delta Asteroschema sp. 1 -23.3 -17.5 8.8 10.7 MC885 J2-527 631

Callogorgia americana delta Asteroschema sp. 1 -20.2 -17.8 11.5 9.6 VK826 J2-540 541

Callogorgia americana delta Asteroschema sp. 1 -21.4 -16.9 -- 10.8 VK826 J2-540 543

Callogorgia americana delta Asteroschema sp. 1 -21.2 -16.8 -- 9.9 VK826 J2-540 543

Callogorgia americana delta Asteroschema sp. 1 -21.1 -16.9 10.2 10.8 VK826 J2-540 543

Callogorgia americana delta Asteroschema sp. 1 -21.0 -16.3 11.1 11.5 VK826 J2-540 541

Callogorgia americana delta Asteroschema sp. 1 -21.3 -15.4 -- 11.4 VK826 J2-540 540

Muriceides cf. hirta 1a Astrogomphus sp. -18.9 -17.2 11.0 11.4 VK906 J2-534 432

Muriceides cf. hirta 1a Astrogomphus sp. -18.9 -17.3 11.0 11.9 VK906 J2-534 432

Paramuricea biscaya B1 Asteroschema clavigerum -20.8 -17.8 10.2 12.2 DC673 J2-539 2160

Paramuricea biscaya B1 Asteroschema clavigerum -21.1 -16.9 14.9 13.0 DC673 J2-539 2207

Paramuricea biscaya B1 Asteroschema clavigerum -18.5 -14.6 10.9 14.1 DC673 J2-539 2398

Paramuricea biscaya B1 Asteroschema clavigerum -18.3 -14.9 11.3 12.8 DC673 J2-539 2203

Paramuricea biscaya B2 Asteroschema clavigerum -20.9 -15.4 10.6 13.1 DC673 J2-539 2400

Paramuricea sp. B3 Asteroschema sp. 1 -22.6 -21.1 7.1 -- GC246 J2-528 845

Paramuricea sp. B3 Asteroschema sp. 1 -21.5 -17.0 10.5 11.1 MC118 J2-538 884

Paramuricea sp. B3 Asteroschema sp. 1 -21.5 -16.2 10.5 12.0 MC118 J2-538 884

Paramuricea sp. B3 Asteroschema sp. 1 -20.6 -17.7 9.3 11.1 MC118 J2-538 887

Paramuricea sp. E Asteroschema sp. 1 -20.0 -16.8 9.7 10.4 GB299 J2-530 342

Paramuricea sp. E Asteroschema sp. 1 -20.1 -16.7 9.0 10.4 GB299 J2-530 361

Paramuricea sp. E Asteroschema sp. 1 -20.2 -17.4 10.3 11.3 MC751 J2-536 441

Paramuricea sp. E Asteroschema sp. 1 -20.5 -17.6 6.6 10.8 MC751 J2-536 441

Swiftia exserta Astrogomphus -20.9 -15.7 6.6 8.2 MC751 J2-536 440

δ

13C δ15N

Depth (m)
254

Figure 6-4. (A) δ13C of epizoic ophiuroids vs. δ13C of their host corals. (B) δ15N of epizoic 

ophiuroids vs. δ15N of their host corals. The solid line in (A) represents a simple linear 

regression and the broken line in both panels represents equal values on the x- and yaxes.

C. a. delta and their paired ophiuriods Asteroschema sp. 1 had the most variability in carbon and 

nitrogen stable isotope values, but also showed a significant linear relationship between all 

sampled pairs for δ13C (p=0.0014; Figure 6-5c). The tissue 

13C values of ophiuroids associated 

with C. a. delta clustered by site similarly to their paired corals, while spatial variation in the δ15N 

values is hard to discern because of small sample sizes and a small range overall of δ15N values 

(Figure 6-5c,d).

Tissue 

13C values were similar between sites for C. a. americana and their paired ophiuroids 

Asteroschema sp.1 (Figure 6-5a). The tissue δ15N values of the C. a. americana differed markedly 

by site since the three anomalous values were from one site, but their paired ophiuroids 

Asteroschema sp. 1 had similar δ15N values between sites (Figure 6-5b).
255

Figure 6-5. (A) δ13C of associated ophiuroid vs. δ13C of Callogorgia americana americana, (B) 

δ

15N of associated ophiuroid vs. δ15N of Callogorgia americana americana, (C) δ13C 

of associated ophiuroid vs. δ13C of Callogorgia americana delta, (D) δ15N of 

associated ophiuroid vs. δ15N of Callgorgia americana delta.

Paramuricea biscaya B1 and B2 samples were paired with Asteroschema clavigerum individuals 

and had a narrower range of stable isotope values compared to Callogorgia samples, with coral 

δ

13C values ranging from -21‰ to -18‰ and coral δ15N values ranging from 10‰ to 15‰. 

Corresponding ophiuroids had tissue δ13C values ranging from -18‰ to -15‰ and δ15N values 

ranging from 12‰ to 14‰. Paramuricea biscaya B1 and B2 pairs have δ15N values at the high 

end of the overall δ15N distribution (Figure 6-4b), and two P. biscaya B1 pairs had the highest δ13C 

values of all coral-ophiuroid pairs (Figure 6-4a). There is less variability in δ13C and δ15N values 

in Paramuricea sp. B3 and E pairs, and they tended to group close to the center of the overall 

distribution.
256

Muriceides cf. hirta 1a and paired Astrogomphus sp. individuals had δ13C and δ15N values near 

the densest areas in the overall distributions (Figure 6-4). The pair of Swiftia exserta and 

Astrogomphus sp. had tissue δ13C values of -21‰ for the coral and -15‰ for the ophiuroid, and 

δ

15N values of 7‰ for the coral and 8‰ for the ophiuroid (Figure 6-4), putting this pair at the very 

high end of the δ13C range, and very low end of the δ15N range.

6.3.3 Macrofaunal Community Associated with Lophelia pertusa

In the coral pot collection from the MC751 study site, the associated macrofauna had tissue 

13C 

values ranging from -28.5 to -16.6‰ and δ15N values ranging from 5.3 to 10.8‰ (Figure 6-6a). In 

the collection from GB535, the associated fauna had 

13C values ranging from -22.8 to -17.6‰ 

and δ15N values from 7.5 to 13.8‰ (Figure 6-6b).

Figure 6-6. (A) δ15N vs. δ13C of Lophelia pertusa and associated macrofauna from quantitative 

coral pot collections from MC751 (dive J2-436) and (B) GB535 (dive J2-531).

6.4 DISCUSSION

6.4.1 Nutrition of deepwater corals

The majority of coral species had tissue 

13C and δ15N values consistent with nutrition primarily 

derived from surface primary productivity, but the more variable and more negative 

13C values 
257

and δ15N values in Callogorgia americana delta provide the strongest evidence to date of a 

nutritional link between a deepwater coral species and hydrocarbon seep primary production 

(Table 6-1, Figure 6-2). Other authors have suggested such a link based on the tendency of corals 

to occur in close proximity to seeps (Hovland and Risk 2003). However, previous stable isotope 

analysis of coral tissue and skeleton suggested that, at least in the GoM, the association between 

corals and seeps is driven more by the availability of hard substrate in the form of authigenic 

carbonate, a feature unique to past or present seeps on the Gulf’s otherwise muddy seafloor, and 

that corals settle after seepage has become mostly inactive (Becker et al. 2009).

Recent work incorporating phylogenetic and ecological niche modeling that was part of the current 

project showed that the occurrence of C. a. delta was positively correlated with the presence of 

active seepage and was able to settle and grow even on small pieces of hard substrate such as coral 

rubble or clam shells (Quattrini et al. 2013; Section 9.2 of this report). The ability of this species 

to tolerate chemical conditions of the seep environment (exposure to hydrocarbons and sulfides 

and low oxygen concentration) and take advantage of a local source of primary production may 

release it from competition, since other corals relying on surface production are limited to areas 

with flow regimes producing sufficient food delivery, such as local topographic highs which 

accelerate currents and interact with internal waves to resuspend sediment organic matter and

increase feeding opportunities (Genin et al. 1986, Davies et al. 2009, Duineveld et al. 2012). 

Indeed, the distribution of Paramuricea spp. in the GoM, whose stable isotope values are 

indicative of photosynthesis-based nutrition, is most commonly observed on local topographic 

highs (Doughty et al. in press).

Figure 6-7. Small tube worm aggregations interspersed with colonies of Callogorgia americana

delta at MC885.
258

6.4.2 Nutritional Associations Between Corals and their Epizoic Ophiuroids

The significant correlation between 

13C values in epizoic ophiuroids and their host gorgonian 

corals, indicates either a direct trophic interaction between the two organisms or that they share a 

food source (Figure 6-4a). The latter is more likely based on the results of other studies that 

observed the behavior and gut contents of epizoic ophiuroids from other regions (Emson and 

Woodley 1987, Fujita and Ohta 1988). In these studies, the authors concluded that the ophiuroids 

are suspension feeders and are not predating the corals, since ophiuroids were observed capturing 

suspended particles from the water column, host corals were not damaged, and no coral polyps 

were found in the gut contents of the ophiuroids. The δ15N values, although not significantly 

correlated, are also similar between ophiuroids and host corals (excepting the corals with 

anomalously high δ15N values), and the δ15N of ophiuroids do not show a consistent trophic 

enrichment (+3.4‰; (Minagawa and Wada 1984), further supporting that the ophiuroids are not 

preying upon the coral, but rather share a common food source. 

Together, the previous observations and the current stable isotope data indicate that the ophiuroidgorgonian association benefits the ophiuroid by providing access to a food source that is similar to 

the food source of the coral, but the effect of the association on the coral is not known. The 

association could be parasitic (e.g. ophiuroids stealing food from polyps), mutualistic (e.g.

ophiuroids help to prevent sedimentation by removing particles from polyps), or commensal (e.g.

ophiuroids simply use the vertical structure of the coral to surmount the benthic boundary layer 

and capture particulate matter and prey from the water column, or they eat a byproduct of the coral 

such as mucus or feces). 

6.4.3 Nutritional Sources for Fauna Associated with Lophelia pertusa

In the two coral pot collections of Lophelia pertusa and its associated community, the majority of 

fauna had tissue stable isotope values indicative of primarily photosynthesis-derived nutrition 

(Gearing et al. 1984) ( Figure 6-4). Although, in the collection from MC751, the δ

15N values of 

some organisms were lighter than the GB535 collection, and the four lollipop sponges had 

13C 

values in between -27.6 and -26.1‰ and one hesionid polychaete had a tissue 

13C value of -

28.5‰, indicating that these animals may derive some nutrition from seep primary production 

(Table 6-1, Figure 6-6). This is quite possible, since the coral pot collection from MC751 was 

made in an area with L. pertusa attached to tube worms and contained vestimentiferan tube worms 

(Figure 6-8).
259

Figure 6-8. Lophelia pertusa growing on vestimentiferan tube worms with Acesta sp at MC751.
260

7 LOPHELIA PERTUSA LABORATORY EXPERIMENTS

7.1 INTRODUCTION

Ocean change is expected to manifest itself in a variety of ways. Due to the high density and 

specific heat of seawater, the oceans store a large portion of the heat produced by the greenhouse 

effect and global warming (Levitus et al. 2000). Since the 1950s, most of this storage has occurred 

within the upper 700 m of the Atlantic Ocean (Levitus and Boyer 2005), with observed temperature 

increases ranging from 0.1 to 0.2oC (Barnett et al. 2005). Increasing seawater temperature 

decreases the solubility of oxygen and enhances thermal stratification of the water column 

(Keeling et al. 2010). Finally, the increased flux of anthropogenic CO2 to the surface ocean results 

in ocean acidification (Raven et al. 2005). These changes, acting both independently and 

collectively, may challenge the persistence of marine organisms and their associated communities 

in the future global ocean. 

Maximal performance of physiological functions in a number of marine organisms occurs within 

a relatively narrow range of environmental conditions. Temperature is perhaps the primary 

physical driver of the limits to species distribution and abundance (Gaston 2003). The stability of 

both proteins and cell membranes are dependent on temperature (reviewed in Hofmann and 

Todgham 2010), thereby exerting considerable effects on organismal survivorship. Dissolved 

oxygen concentrations are critical to the maintenance of respiration, and the energetic requirements 

of most eukaryotes are sustained by aerobic respiration. pH is of similar significance to 

physiological functioning, particularly with respect to acid-base balance (Pörtner et al. 2005), and 

the regulation of this balance is often correlated to an organisms’ metabolic rate (e.g. Goffredi and 

Childress 2001, Pane and Barry 2007). As a result of ocean acidification, changing seawater pH

will distort the carbonate chemistry of seawater with particularly negative effects on the growth of 

calcareous species. 

Given the relatively narrow range of physical conditions associated with the habitat of L. pertusa, 

changes in these variables may alter its current distribution via negative effects on survivorship 

and growth. Temperature likely controls both the upper and lower bathymetric limits of L. pertusa

worldwide (Frederiksen et al. 1992, Roberts et al. 2006). Recent long-term data from the Viosca 

Knoll L. pertusa reefs show ranges of 6.5-11.6oC with seasonal fluctuations of up to 5oC (Mienis 

et al. 2012); furthermore, daily fluctuations of up to 1oC have also been reported within the area 

(Davies et al. 2010). Dissolved oxygen is relevant to L. pertusa persistence because the corals 

appear to be near their lower limits in the GoM. Near L. pertusa habitats on Viosca Knoll, DO was 

measured between 2.6 and 3.2 mL·L-1(Schroeder 2002), while in the North Atlantic it is commonly 

between 3 and 6 mL·L-1(Dodds et al. 2007). pH is widely considered to be one of the most 

important factors related to coral calcification (Doney et al. 2009), and data from the L. pertusa 

reefs in the GoM show pH ranging from 7.86-8.03, with a mean around 7.90 (Lunden et al. 2013). 

The purpose of the present study was therefore to employ short-term experiments in the laboratory 

to investigate L. pertusa’s responses to changes in temperature, dissolved oxygen, and pH (and 

aragonite saturation state). 

Despite the above-referenced changes to the marine environment, research has predominately 

focused on easily-accessible, tractable, nearshore systems such as rocky intertidal communities 
261

(e.g. Helmuth et al. 2006), coral reefs (e.g. Hughes et al. 2003), seagrass beds (e.g. Orth et al. 

2006), and kelp forests (e.g. Henkel et al. 2009), among others. Investigations of climate change 

impacts in extreme environments are considerably less common, particularly due to the logistical 

and financial constraints associated with collection and maintenance of target species. In the past 

several years, investigations of climate change effects in remote environments (e.g. high-latitude 

regions and deep-sea communities) have emerged as new priorities for study (Hofmann et al. 

2010), as well as presently poorly-understood biological impacts of ocean acidification (Garrard 

et al. 2012).

Physiological investigations of deep-sea organisms in the laboratory typically require sophisticated 

holding aquaria that replicate the natural environments of the study species. This has primarily 

been manifested in the form of flow-through aquaria that receive high-quality and presumably 

uncontaminated natural seawater from offshore areas (e.g. Mortensen 2001, Olariaga et al. 2009, 

Naumann et al. 2011). However, flow-through systems require close proximity to a natural 

seawater source, restricting most research to coastal research facilities. Furthermore, flow-through 

systems may be compromised in the event of an unforeseen disturbance to the seawater supply, 

such as an oil spill, pathogen outbreak, or changing seawater chemistry due to ocean acidification. 

An alternative to the flow-through system is a recirculating, or “closed” system, which functions 

independently of an offshore seawater supply and remains under the complete autonomy of the 

facility or researchers maintaining it. 

Recirculating aquaria require efficient and vigorous filtration to prevent the accumulation of toxic 

waste products and detritus within the system. Three primary modes of filtration are generally used 

for recirculating aquaria: biological, chemical, and mechanical. Biological filtration refers to the 

decomposition of organic and inorganic wastes produced by the aquarium inhabitants, and relies 

heavily on microbial processes such as nitrification (the oxidation of ammonium to nitrite then 

nitrate by aerobic bacteria) and denitrification (the reduction of nitrate to nitrite by anaerobic 

bacteria). Both aerobic and anaerobic bacteria proliferate within sediments and on complex 

structures with high surface area, thus necessitating platforms such as sand, gravel, or convoluted 

surfaces as substrata within the system. Chemical filtration involves the removal of organic 

compounds lacking nitrogen, such as dissolved organic carbon (Delbeek and Sprung, 2005), and 

can be accomplished via granular activated carbon (GAC), phosphate adsorption media, and 

protein skimming. While any of these methods are commonly used, protein skimming is 

considered to be the most effective as it removes intact organic molecules prior to decomposition 

(Delbeek and Sprung, 2005). Finally, mechanical filtration is the physical removal of particulate 

matter within the aquarium, and relies heavily on sponge pads and other fibrous, screened materials 

that can trap particulate matter. Mechanical filtration can also be supplemented by an ultraviolet 

light sterilizer, which kills pathogenic bacteria that can accumulate and harm the aquarium 

livestock. 

In order to manipulate variables relevant to climate change, several methods are available. To 

simulate changes in seawater pH, common perturbations include CO2 bubbling and strong acid 

addition. However, only bubbling of CO2 accurately replicates the effects of ocean acidification 

via increases in pCO2 and dissolved inorganic carbon. Addition of strong acids to reduce pH results 

in a decrease in total alkalinity, a parameter that is not expected to change as a result of ocean 

acidification. Therefore, the recommended method for simulating ocean acidification in the 
262

laboratory is bubbling of pure or pre-mixed CO2 into aquaria (Gattuso et al. 2010). However, one 

caveat of using synthetic seawater in recirculating aquaria is the high buffering capacity 

characteristic of synthetic sea salts. Artificial salt manufacturers intentionally augment the 

buffering capacity of artificial salts primarily via bicarbonate additions to prevent the pH crashes 

that occur frequently in recirculating aquaria with high livestock loads, particularly due to the 

release of hydrogen ions during denitrification (Delbeek and Sprung, 2005). This excess buffering 

capacity results in an abnormally high total alkalinity of the seawater (around 3600 μmol·kg-1

compared to 2300 μmol·kg-1of natural seawater at a salinity of 35 ppt), therefore limiting the 

environmental relevance of acidification experiments using synthetic sea salts.

Manipulating dissolved oxygen in the laboratory is primarily accomplished by degasification, 

which involves bubbling an inert gas, such as nitrogen, into the seawater. This method has been 

used previously in several laboratory studies of aquatic organisms (e.g. Breitburg et al. 1997, Geist 

et al. 2006), including cold-water corals (Dodds et al. 2007). However, methods for maintaining 

targeted concentrations of dissolved oxygen in the absence of mass-flow controllers are largely 

absent from the literature. 

Here we describe the development and maintenance of recirculating aquaria for maintaining deepsea corals and associated fauna independent of a natural seawater supply. We also describe the 

development, maintenance, and manipulation of smaller, recirculating aquaria used for short-term 

experiments on the cold-water coral Lophelia pertusa. We share our findings and experiences from 

this work with the goal of promoting experimental investigations on traditionally under-studied 

organisms, particularly with respect to new directions in climate change research. 

7.2 DEVELOPMENT OF RECIRCULATING AQUARIA FOR EXPERIMENTATION WITH 

DEEP-SEA CORALS 

7.2.1 Methods

7.2.1.1 Maintenance Aquaria Design and Setup

Two replicated aquaria systems were constructed as primary holding tanks for the animals (Figure 

7-1) shows a representative example of these systems). The two systems were maintained in 

different locations in the laboratory: one system was constructed in a constant-temperature room, 

and the other was constructed in the laboratory. Temperature of the laboratory system was 

controlled by a flow-through chiller (TECO®), and a drop-in coil chiller (Aqua Logic®) was 

installed in the constant-temperature room system to prevent temperature fluctuations in the event 

of thermostat failures in the room. Each system consisted of a 100 gallon holding tank and a 50 

gallon sump tank – the constant-temperature room system consisted of all-glass aquaria and the 

laboratory system consisted of fiberglass insulated tanks (Aquatic EcoSystems) to achieve 

temperature stability. The sump tank was divided into three compartments using 1⁄2” plexiglass 

baffles for the different filtration applications (biological, chemical, mechanical). Circulation was 

controlled by a Quiet One 6000 submersible pump, with a flow rate of 1000 gallons per hour and 

a turnover rate of ~seven times per hour. A Koralia® HydorTM powerhead (1050 gallons per hour) 

interfaced with an OceanPulse® DuoTM wavemaker provided water movement within the holding 

tank in 90-second cycles. 
263

Tank filtration was identical in each system, and was accomplished via several methods. Biological 

filtration in the sump was accomplished via a Jaubert plenum (Jaubert, 1989). The plenum itself 

was constructed using 0.3” plastic egg crate lighting panel wrapped in fiberglass window screen. 

The plenum was positioned 1” from the bottom of the sump by 3⁄4” inner diameter poly-vinyl 

chloride (PVC) pipes. Florida crushed coral (20 pounds) was placed directly above the plenum, 

and sand (90 pounds, sieved at 250 μm) collected from the New Jersey shore was placed directly 

above the crushed coral. Two small rocks (2-3 pounds each, 3” in diameter) with macroalgal 

growth, also collected from the New Jersey shore, were added to the sand bed. Lighting of the 

sump was provided by a 40 watt incandescent bulb operating on 12-hour light/dark cycles. A small 

50 watt submersible heater (Tetra®) was added beneath the plenum to facilitate water diffusion 

through the sand bed. Mechanical and chemical filtration was accomplished using a protein 

skimmer/foam fractionator (Coralife® Super SkimmerTM 125G), which was cleaned weekly. Two 

sponge filters placed in the holding tank provided supplementary mechanical filtration. Finally, an 

untra-violet (UV) sterilizer (Coralife® Turbo Twist 3XTM with 9 watt UV bulb) was placed 

immediately before the submersible return pump to control algal growth and water-borne 

pathogens. Biweekly water changes (15-20% system volume) were also performed to limit 

nitrogenous and organic waste buildup and replace micronutrients and trace metals.

Figure 7-1. Representative example of maintenance aquarium setup. The upper 

aquarium is the display tank and held the corals and associates. Below 

the aquarium is the sump tank and requisite filtration compartments.

7.2.1.2 Experimental Aquaria Design and Setup

In order to maintain stability and consistency within the maintenance tanks, three smaller, all-glass 

aquaria were used for experimental testing. This design provided tight control and manipulation 

of environmental parameters, as well as a cost-effective means to perform replicated experiments. 

The experimental aquaria used were 20 gallon all-glass aquaria (24" x 13" x 17") covered with 1⁄4” 

plexiglass and fitted with individual filtration units (AquaClear® 30) in a constant-temperature 
264

room. Each filtration unit contained components for the three primary filtration types: a foam insert 

to remove debris and particulates (mechanical filtration), a granular-activated carbon insert 

(chemical filtration), and ceramic porous “bio-balls” to foster growth and proliferation of 

beneficial bacterial communities (biological filtration). To supplement water circulation provided 

by the filter, each aquarium was fitted with a circuit of Tygon® tubing powered by a submersible 

pump (Maxi-Jet). 

7.2.1.3 Animal Collection, Maintenance, and Processing

All animals were collected from the Viosca Knoll leasing area in the northern GoM using the 

remotely-operated vehicle Jason II on two separate cruises in 2009 and 2010 with the necessary 

permits from the U.S. Department of Interior and NOAA National Marine Fisheries Service. The 

primary sampling locations within the area were lease blocks VK906 and VK826 (390-550 m 

depth). The VK826 L. pertusa reef is one of the most well-studied in the GoM (e.g. Cordes et al. 

2008, Davies et al. 2010), and long-term data (11 months) show temperatures ranging from 6.5-

11.6°C, salinity from 34.9-35.4, and mean current speed to be 8 cm s-1(with peaks at 38 cm s-1, 

Mienes et al. 2012). At VK906, long-term (8 months) data show temperature ranging from 8-

12.4°C and short-term data (12 hours) show salinity ranging from 34.9-35.5 (TDI-Brooks Intl. 

unpublished). To reflect these in situ conditions, the aquaria were maintained at a temperature of 

8°C and a salinity of 35 ppt. Seawater was prepared regularly using distilled water and Instant 

Ocean® sea salt. Temperature was measured daily using a glass thermometer and salinity was 

measured daily using a refractometer (VitalSine®) that was calibrated daily. 

Animals were transported to the laboratory in 4 liter screw-top polypropylene containers on ice 

via overnight air and ground transportation (total transit time was less than 24 hours). Upon return 

to the laboratory, each container was bubbled for 3 minutes with air and received 250 mL of 

maintenance aquaria seawater every hour for four hours. After transfer to the maintenance aquaria, 

corals were broadcast-fed MarineSnow® plankton diet three times weekly. MarineSnow® is a 

commercially-available mixture of zooplankton and phytoplankton that replicates the naturallyoccurring particulate organic matter (typically known as “marine snow”) that is found suspended 

throughout the water column, and is frequently observed at cold-water coral habitats (Frederiksen 

et al. 1992; Brooke et al. 2009). Mechanical filtration was suspended for one hour following each 

feeding. Galatheoid crabs in the aquaria were target-fed crushed frozen Mysis shrimp (Hikari Sales 

U.S.A., Inc.). 

7.2.1.4 Carbonate Chemistry Manipulations

To reduce the elevated total alkalinity characteristic of synthetic seawater, 12.1 N HCl was added 

to seawater used in acidification experiments in order to reach a total alkalinity of 2,300 μmol·kg1

, the mean total alkalinity of natural cold-water coral reefs in the GoM (Lunden et al. 2013). 

The amount of HCl added was determined by the following equation

VHCl =

[TAi-TAf]*msw

NHCl

where

VHCl is the volume of HCl to be added in mL
265

TAi is the initial total alkalinity of Instant Ocean at salinity 35 ppt in μmol·kg-1

TAf is the final (desired) total alkalinity of 2,300 μmol·kg-1

msw is the mass of seawater to be acidified in kg 

NHCl is the normality (molarity) of HCl in μmol·mL-1

To acidify a given volume of seawater in gallons, one would first determine the mass of seawater 

by:

msw = 3.785Vsw*Dsw

where 

msw is the mass of seawater

Vsw is the volume of seawater in gallons

Dsw is the density of seawater, 1.029 kg·L-1

3.785 is a conversion factor to convert gallons to liters

As an example, to acidify 20 gallons of Instant Ocean seawater at salinity 35 ppt and a total 

alkalinity of 3,600 μmol·kg-1 with hydrochloric acid at a concentration of 12,100 μmol·mL-1, 

msw = (3.785*20)*1.029

msw = 77.895 kg

and

VHCl =

[3600-2300]*77.895

12100

VHCl = 4.51 mL

Therefore, 4.51 mL of 12.1 N HCl would bring 20 gallons of 35 ppt Instant Ocean seawater to a 

total alkalinity of 2300 μmol·kg-1. 

Total alkalinity was measured at 22°C according to SOP3b (Dickson et al. 2007) using a MettlerToledo DL15 autotitrator with 0.1 mol L-1 HCl in 0.6 mol L-1 NaCl solution and calibrated against 

certified reference materials (Dickson Lab, Scripps Institution of Oceanography). After seawater 

was brought to the target total alkalinity of 2,300 μmol·kg-1, it was aerated overnight with an air 

pump and air stone to drive off excess CO2 from the acid addition step. After 48 hours of aeration, 

the seawater reached an ambient pH of 7.90 and was ready to be used for the experimental trials. 

The recommended pH scale for ocean acidification experiments is the total hydrogen scale, which 

accounts for both free hydrogen ions as well as hydrogen ions complexed with water (H2O) and 

sulfate (SO4

2-

) (Dickson 2010). In order to control pH on the total scale, Tris/HCl buffers of a 

similar ionic strength of seawater (0.7 M) can be used. For these purposes, all pH electrodes were 

calibrated weekly with Tris/HCl buffers using the recipes of Nemzer and Dickson (2005). 

Manipulation of pH was accomplished via bubbling of pure CO2 gas into the aquarium. CO2, 

purchased from Airgas, was delivered from a five-pound cylinder to the aquaria through a CO2

dosing system purchased from Drs. Foster and Smith. Bubbling of CO2 was controlled by a pH 
266

monitor (Pinpoint, American Marine Inc.) interfaced with a pH electrode in the aquarium and a 

solenoid valve on the gas regulator. When pH rose above a pre-determined setpoint appropriate 

for the experiment, the solenoid valve would open, releasing CO2. CO2 would then dissolve into 

the aquarium seawater through a CO2 reactor. The flow rate of CO2 was adjusted by a needle valve 

on the solenoid regulator, and monitored with a bubble counter. Using this system, we sought to 

control pH at 7.90, 7.75, and 7.60 for a period of two weeks. pH was recorded daily over the course 

of each experimental trial.

7.2.1.5 Dissolved Oxygen Manipulations

Dissolved oxygen concentrations were controlled via bubbling with oxygen-free nitrogen gas 

independently into each aquarium. Control of nitrogen flow was accomplished via CGA 580 dualstage gas regulators with output valve controls (Airgas). First, the output valve was opened slightly

to release a slow bleed of nitrogen into the aquarium, followed by adjusting the output pressure to 

4 psi. Since the experimental aquaria were open systems (i.e. not closed off from atmospheric gas 

exchange), oxygen was able to re-enter the aquarium through surface diffusion. To achieve 

targeted dissolved oxygen concentrations, the output valve was carefully positioned to allow the 

bleed of nitrogen (and subsequent removal of oxygen) to equilibrate with the surface diffusion of 

oxygen and achieve the desired dissolved oxygen concentration. Using this system, we sought to 

control dissolved oxygen at 5, 3, and 1 mL·L-1for a period of two weeks.

7.2.2 Results

7.2.2.1 Maintenance Aquaria

The maintenance aquaria described above provide a stable setting that closely resembles the 

physical conditions (with the exception of pressure) experienced by cold-water corals and 

associated fauna in the GoM. Temperature has remained constant (8oC) in both recirculating 

aquaria, partially due to the back-up support of aquarium chillers on emergency power in the event 

of malfunctions. Salinity has remained stable at 35 ppt through daily checks and occasional 

additions of distilled water. Nutrients (ammonia, nitrate, nitrite) have remained undetectable for 

several years, and have been controlled primarily via our filtration setup with supplemental partial 

water changes. 

7.2.2.2 Experimental Aquaria

The experimental aquaria described above also provided a stable setting for experiments on L. 

pertusa. Temperature remained constant throughout all experiments, and the 1⁄4” plexiglass lids 

effectively reduced evaporation and thus changes in salinity. Furthermore, the filtration units 

described above were effective in keeping ammonia, nitrate, and nitrite levels below 1.0 ppm at 

all times. The Tygon® tubing circuit powered by the Maxi-Jet pump facilitated complete 

circulation of the water and prevented accumulation of “dead zones” within each experimental 

aquarium.

7.2.2.3 Animal Collection, Maintenance, and Processing

Based on our observations, animals collected within 48 hours of shipping had the lowest mortality 

rates upon return to the laboratory. There was also a noticeable effect of transportation mode, with 
267

animals shipped via air having significantly higher survivorship (100%) than animals shipped via 

ground (30-40%). Corals began expanding their polyps approximately three days after the initial 

transfer to the maintenance aquaria, and were fully expanded within seven days of transfer. When 

transferred to experimental aquaria, corals began expanding their polyps within one hour and all 

polyps were fully expanded within twelve hours.

Several species of deep-water invertebrates have survived continuously since 2009 in our holding 

tanks, supporting their efficacy. Time-lapse imagery of the aquaria shows episodic opening and 

closing of Lophelia pertusa polyps, although this was not periodic and aligned closely with feeding 

intervals. Time-lapse imagery also showed movement of the associated gastropod Coralliophila

sp. and the crustacean Eumunida picta, opening and closing of serpulid worms, and construction 

of parchment tubes on coral skeletons and aquarium glass by the polychaete Eunice sp. We also 

observed several molting events of the crustacean E. picta, suggesting it received sufficient 

nutrition to maintain growth in the aquarium. While in situ behavioral analyses of cold-water coral 

communities are currently lacking, these observations agree with prior aquarium observations of 

these fauna in flow-through systems (Mortensen 2001, Mueller et al. 2013). No spawning of 

gametes or settling of larvae was apparent; however, spawning of L. pertusa in the field is 

attributed to seasonal environmental cues in the North Atlantic (Waller and Tyler 2005) and the 

GoM (Morrison et al. 2011). 

7.2.2.4 Carbonate Chemistry Manipulations

The addition of hydrochloric acid to synthetic seawater effectively reduced the total alkalinity to 

the targeted value of 2300 μmol·kg-1. Because the method used to measure total alkalinity 

generally applies to the typical oceanic range of 2,000 to 2,500 μmol·kg-1(Dickson et al. 2007), 

our initial measurements of total alkalinity in synthetic seawater were often underestimated by up 

to 400 μmol·kg-1. This often necessitated a second addition of a smaller volume of HCl to reach 

2,300 μmol·kg-1. Once the target total alkalinity was reached, it did not change significantly over 

the course of our experimental trials (Figure 7-2).

Figure 7-2. Actual and target values of total alkalinity in carbonate chemistry manipulations. 

Error bars represent standard deviation of mean actual (observed) total alkalinity.

The off-the-shelf CO2 systems used here were primarily designed to control CO2 levels for plants 

in freshwater aquaria; however, they provided an effective means to reach the targeted pH values 

0

500

1000

1500

2000

2500

3000

Total alkalinity (

ambient low very low

μmol·kg

-

1

)

Treatment

Actual Target
268

within the scope of this study. One five-pound cylinder of CO2 per aquarium was sufficient to 

complete all pH experiments over the course of our experimental trials, which lasted over several 

months. Measured pH for each trial was 7.90 ± 0.08, 7.78 ± 0.04, and 7.67 ± 0.10 (mean ± 

s.d.,Figure 7-3). The variance in pH from our experimental trials is of a similar order to other 

recent ocean acidification studies using CO2 bubbling (e.g. Rodolfo-Metalpa et al. 2011; Edmunds 

2012; Form and Riebesell 2012). We observed the greatest variance in pH in the lowest treatment 

(pH 7.60), where CO2 bubbling was most active. In rare, isolated occasions during the pH 7.60 

trial, CO2 bubbling was temporarily disrupted due to faults with the CO2 controller. However, 

daily checks of the systems were sufficient to identify deficient controllers in our trials and 

maintain our targeted pH values.

Figure 7-3. Actual and target values of pH in carbonate chemistry manipulations. Error bars 

represent standard deviation of mean actual (observed) pH values.

7.2.2.5 Dissolved Oxygen Manipulations

Dissolved oxygen was maintained at target levels for each treatment. Measured DO for each trial 

was 5.32 ± 0.28 mL·L-1, 2.92 ± 0.21 mL·L-1, and 1.57 ± 0.28 mL·L-1 (mean ± s.d., Figure 7-4). 

Although we sought to reach 1 mL·L-1, the minimum oxygen concentration that we were able to 

achieve was 1.57 mL·L-1. It is likely that the diffusion of atmospheric oxygen back into the 

aquarium restricted reaching our minimum target DO. Nevertheless, our methods provided an 

effective way to manipulate and control DO values without the use of a mass-flow controller.

Figure 7-4. Actual and target values of dissolved oxygen in oxygen manipulations. Error bars 

represent standard deviation of mean actual (observed) dissolved oxygen values.

0

1

2

3

4

5

6

Dissolved Oxygen (mL·L

high middle low

-

1

)

Treatment

Actual Target
269

7.2.3 Discussion

This study describes an effective and practical means to maintain deep-water invertebrates for 

multiple years in the laboratory, independent of a natural seawater supply, including the 

ecologically relevant cold-water coral L. pertusa. In addition, our trials testing the manipulation of 

variables related to climate change (pH, dissolved oxygen) were effective at reaching and 

sustaining target treatment conditions for several weeks. Future work will include trials to assess 

longer-term control of these manipulations.

Because of the logistical challenges associated with collecting and maintaining deep-water corals, 

much of the research on them has been limited to ship-board experiments, and consequently lags 

behind related work on easily accessible shallow-water taxa. To date, only six laboratory-based 

manipulative studies of climate change variables exist for deep-water corals (Brooke et al. 2013, 

Dodds et al. 2007, Form and Riebesell 2012, Maier et al. 2012, Maier et al. 2013a, b), compared 

to the greater than twenty related studies of tropical and sub-tropical corals (as reviewed in 

Andersson et al. 2011). While several factors are responsible for this incongruity – including 

financial and logistical limits to the access of deep-water sites - it is our hope that improvements 

and developments in the husbandry of deep-water corals, including this work, will lead to greater 

insight into their responses to variables relevant to global climate change. 

It is well-known that experiments in the laboratory cannot fully replicate the consortium of 

physical and biological variables observed in the field (e.g. pressure, alterations in current regimes 

and associated pulses of particulate material, interspecific interactions, etc.). However, laboratory 

studies are useful in characterizing responses to discrete perturbations and can help generate new 

avenues of investigation for future studies. Additionally, it is our hope that laboratory experiments 

such as those described here will aid in identifying potential thresholds of tolerance or mechanisms 

of resilience for important taxa in order to inform the management of sensitive deep-sea habitats.

One of the pivotal variables we found to affect cold-water coral endurance in the maintenance 

aquaria was water flow. We initially utilized two powerheads running simultaneously in the 

maintenance aquaria, but observed very few expanded coral polyps with this setup. We observed 

increased polyp expansion after installing a wavemaker to cycle power between the two 

powerheads, which clearly reduced the turbulence experienced by the corals. However, we 

observed maximal polyp expansion after removing one of the powerheads altogether, resulting in 

oscillations of turbulence and rest on 90-second cycles. On a related note, we also observed 

maximal polyp expansion when the sump outlets were positioned horizontally to distribute water 

across the surface layer of the aquarium. This positioning resulted in weakened water turbulence 

as opposed to vigorous turbulence when the outlets were positioned vertically, and the corals in 

our system appeared to be sensitive to this arrangement. Investigators seeking to utilize similar 

systems may need to modify one or both of these controls on water flow to simulate the natural 

environment or needs of species acclimatized to different flow regimes.

During the course of our studies, we tested several shipping methods for transporting animals to 

our laboratory in 2009 and 2010. We found that shipping via next-day air resulted in 100% 

survivorship of animals. While often more economical, ground transportation generally exposes 

the animals to greater disturbance during transit. We recommend air travel whenever appropriate 

and possible.
270

7.3 OBSERVATIONS OF FAUNA IN LABORATORY AQUARIA

Behavioral observations were recorded by time-lapse photography in the maintenance aquaria. 

Still photographs were taken hourly with a Canon® EOS 50 digital camera controlled by a Canon®

TC-80N3 remote timer. The camera was positioned approximately one (1) meter from the 

aquarium. Animal movement rates were quantified using a scale bar in the frame of the camera 

and distance was standardized by the diameter of PVC pipes (5 cm).

7.3.1 Lophelia pertusa

For each frame with sufficient photo quality, the number of extended polyps on each nubbin was 

counted and recorded. The percentage of visible polyps per nubbin was then correlated against a 

continuous time cycle divided into twenty-four-hour resolution periods. No significant pattern of 

coral activity was observed, though a higher than average percentage of extended coral polyps was 

observed in the period immediately after a feeding event (Marine Snow®). The corals did not show 

evidence of anticipating food delivery, despite maintaining a regular feeding schedule. 

During the early experimental trials, very few polyps were visible by researchers entering the cold 

room. It was later determined that the vibrations from opening the door induced retraction. 

Although a causal relationship could be not evaluated, the corals were often retracted when the 

squat lobster was visible in close proximity to the nubbins. It is possible that this coral retraction 

is a distinct, interspecific response, though it may be that source-nonspecific vicinal vibrations 

induce instinctual retraction. 

7.3.2 Coralliophila sp.

The aquarium observations included Coralliophila sp., a genus of coral eating snail commonly 

found in association with Lophelia reefs. Although the snails are known to be corallivorous

(Brawley and Adey 1982) no photographs from the time-lapse directly recorded this feeding 

behavior. Snails were observed on the corallium, but never on the skeleton immediately 

surrounding the calyx. It was not uncommon that snails would remain stationary for several days 

between relocating, then expend significant effort to reposition over the course of a few hours. 

Minor adjustments, such as changing orientation or displacement of less than 5 cm, were frequent. 

During a ten hour period on November 15th, 2011, one specimen of Coralliophila sp. changed its 

position at a maximum rate of 10 to 15 cm per hour, the highest rate observed during time-lapse 

recordings. It is not known what motivated such a significant displacement as its final destination 

was beyond the scope of the camera. 

7.3.3 Eunice sp. 

Previous studies have detailed the mutualism between Lophelia pertusa and the polychaete worm, 

Eunice norvegica (Roberts 2005, Mueller et al. 2013). Using a similar time-lapse technique, 

Roberts (2005) observed the polychaete worm transplant a smaller coral fragment and join the two 

via the secretion of the parchment tube in which the worm resides. The fragment transplant 

required slightly more than one minute to complete, while the parchment tube developed over a 

four month period. It is believed that these parchment tubes form a substrate between branches 

across which the polyps can anastomize. 
271

Over the course of this time-lapse study, coral fragments lying directly on the glass bottom of the 

aquarium would inexplicably shift between photographs. Several frames suggest the squat lobster 

or Eunice worms may disturb smaller fragments not epoxied to PVC base. However, due to the 1-

hour lapse between photographs, it was difficult to conclusively attribute fragment movement to 

the Eunice polychaete worm. The best example of worm aggregation appeared in the lapse 

between 2:58AM and 3:58AM on February 18th, 2012 (Figure 7-5). Although no visible parchment 

tubes were formed during the study period, the previous study (Roberts 2005) consisted of longterm observations starting in October 1998, with parchment tube formation not observed until 

October 2004. 

Figure 7-5. Example of consecutive time-lapse photographs showing 

movement of Lophelia pertusa fragment, likely caused by the 

activity of Eunice sp. inhabiting a small PVC coral mount. Also 

shown is the typical position of the Coralliophila sp. gastropod on 

the Lophelia fragment. 

7.4 PH EXPERIMENTS

7.4.1 Methods

7.4.1.1 Experimental Design and Setup

Each experiment was conducted in a constant-temperature room at Temple University (TU). Three 

20 gallon aquaria (“tall” type: 24" x 13" x 17") with individual filtration units (AquaClear 30) and 

pH controllers (Pinpoint®, American Marine Inc.) were used for each experiment (Figure 7-6). 

Three individual coral nubbins of unique genotype were randomly assigned to each tank for a total 

of nine nubbins per treatment. Each experiment lasted for a total of fifteen days, with an initial 

eight-day conditioning period to allow the corals to acclimate to the tank conditions. Growth was 

measured between days eight and fifteen to obtain a daily growth rate. Mortality was measured 

daily and at the conclusion of each treatment. 
272

The following experiments were conducted:

1. pH: ambient (7.90), low (7.75), very low (7.60)

2.

Figure 7-6. Experimental aquarium (20 gallons) with pH controller setup. 

7.4.1.2 Sample Collection, Preparation, and Maintenance

Colonies of Lophelia pertusa were collected during the 2010 Lophelia II cruise using ROV Jason

II. Coral branches were placed in temperature-insulated bioboxes (volume = ~20 L) at depth. Upon 

return to the surface, corals were kept alive in 5 gallon aquaria in the ship’s constant-temperature 

room. Upon return to port, coral samples were immediately transported overnight to TU.

At TU, corals were maintained in one of two holding tanks (recirculating, 120 gallons and 90 

gallons) at temperature 8°C and salinity 35 ppt. Regular partial water changes (15-20%) were 

performed with seawater made using Instant Ocean® sea salt. Submersible power heads were 

placed in each holding tank to ensure water movement and turbulence sufficient to cause swaying 

of coral polyps. Corals were fed three times weekly using a combination of MarineSnow® 

Plankton Diet (Two Little Fishies, Miami Gardens, FL) and freshly hatched Artemia nauplii. 

Prior to experimental manipulations, coral branches were fixed to 1” PVC male adapters using 

HoldFast epoxy to minimize handling (Figure 7-7). Monofilament line (diameter = 0.30 mm) was 

looped through each PVC adapter to allow for buoyant weighing of the coral branch (see growth 

measurements below). All coral branches weighed less than 60 g in water. For the experiments, 

corals were first fragmented into nubbins using bone cutters. The nubbins were then fixed to 3⁄4” 

PVC male adapters with HoldFast® epoxy resin and secured to a PVC support base. All nubbins 

were subsequently swabbed for genotypic analyses; no mortality resulted from swabbing of 
273

nubbins. After accounting for differences in genotype, nubbins were randomly assigned to one of 

three tanks for each experimental treatment. 

Figure 7-7. Lophelia pertusa attached to 1” PVC male adapter pieces in 

the maintenance aquarium.

The pH experiment consisted of three treatments to compare growth of L. pertusa at ambient pH 

(7.90), low pH (7.75), and very low pH (7.60). Each treatment was conducted on two separate 

groups (henceforth “group 1” and “group 2”) of coral nubbins. Experimental incubations were 

maintained at temperature 8°C and salinity 35 ppt. pH was controlled by injection of CO2 using a 

Pinpoint® pH controller (American Marine Inc., Ridgefield, CT). pH electrodes were calibrated 

weekly using Tris-HCl and AMP-HCl buffers (Dickson et al. 2007). 

The temperature experiment consisted of five treatments to compare growth and mortality of L.

pertusa at 8°C, 10°C, 12°C, 14°C, and 16°C. Experimental incubations were maintained at pH 

7.90 and salinity 35 ppt. The experimental aquaria were maintained in a constant-temperature 

room, and the temperature of the room was adjusted as appropriate for each treatment. 

The dissolved oxygen experiment consisted of three treatments to compare mortality of L. pertusa

under low-level dissolved oxygen (1 mL·L-1), middle-level dissolved oxygen (3 mL·L-1), and highlevel dissolved oxygen (5 mL·L-1

). Experimental incubations were maintained at temperature 8°C 

and salinity 35 ppt. To manipulate dissolved oxygen concentrations, oxygen-free nitroge gas was 

bubbled into each tank through a CO2 reactor (Aqua Medic 1000). Flow of nitrogen was controlled 

with CGA 580 regulators (Airgas). Dissolved oxygen concentration in each aquarium was 

recorded each day with an Orion 5 Star DO/pH meter (calibrated daily). 
274

7.4.1.3 Seawater Preparation and Analyses

Experimental seawater was prepared using Instant Ocean® sea salt at a salinity of 35 ppt. Since 

Instant Ocean® produces seawater with a total alkalinity of approximately 3600 μmol·kg-1(1.5X

that of natural oceanic values), 12.1 N HCl was added to reduce the total alkalinity to 2300 

μmol·kg-1(mean total alkalinity at GoM L. pertusa reefs, Lunden et al. 2013). The seawater was 

then bubbled with oxygen for ~24 hours to drive off excess CO2 and to restore pH to ambient 

conditions (7.90). 

Total alkalinity was measured twice weekly in each aquarium by potentiometric open-cell titration 

using a Mettler-Toledo DL15 automatic titrator according to SOP3b (Dickson et al. 2007) with 

certified reference materials courtesy of A. Dickson (Scripps). pH (total hydrogen scale) was 

recorded daily using the Pinpoint® pH controller. The aragonite saturation state was calculated 

using CO2SYS (Pierrot et al. 2006) with total alkalinity, pH, temperature, and salinity as input 

variables. Nutrient concentrations (ammonia [NH3], nitrate [NO3

-

], and nitrite [NO2

-

]) were 

measured weekly using API® aquarium test kits.

7.4.1.4 Survivorship Measurements

Survivorship was assessed by daily observations of polyp tissue presence and behavior. Final 

survivorship counts were taken 3 to 4 days following the end of an experiment after transfer to the 

maintenance tank, as in Brooke et al. (2013). Survivorship is reported as cumulative survivorship, 

the percentage of live polyps at the end of each treatment compared to the original number of live 

polyps at the beginning of the experimental series.

7.4.1.5 Growth Measurements

Each coral nubbin was weighed at the start and end of the experimental period (seven days) by the 

buoyant weight technique (Davies et al. 1989) using a Denver Instruments SI-64 analytical balance 

(d = 0.1 mg). A weighing chamber was constructed using 1⁄2” plexiglass to prevent air movement 

from disturbing the balance. Each coral was transported from its respective aquarium to the 

weighing chamber in a four liter Pyrex® beaker and suspended from the balance. The buoyant 

weight was recorded only after the coral nubbin stabilized (typically after 2 minutes). Each coral 

nubbin was weighed three times to determine measurement precision (~2-3 mg). Seawater density 

was determined by buoyantly weighing a 2.5 cm2aluminum block with known density (2.7 g·cm3

). 

Coral weight in air (i.e. dry weight) was calculated by the following equation: 

Wa =

Ww

1 −

Dw

SD

Where

Wa = coral weight in air (dry weight) 

Ww = coral weight in water (buoyant weight)

Dw = density of seawater

SD = coral skeletal density (= 2.82 g·cm-3, taken from Lunden et al. 2013)
275

Coral growth rate is reported as percent growth per day (%·d-1), which was calculated by the 

equation:

Gt = 100 ×

Mt2 − Mt1

Mt1(T2 − T1)

Where 

Gt = growth rate as %·d-1

Mt2 = mass (mg, dry weight) at time 2 (end of experimental period, day fifteen)

Mt1 = mass (mg, dry weight) at time 1 (start of experimental period, day eight)

T2 = time 2 (end of experimental period, day fifteen)

T1 = time 1 (start of experimental period, day eight)

7.4.1.6 Statistical Analyses

We used one-way ANOVA and Tukey’s honestly significant differences (HSD) to test for 

significances in survivorship and growth rates across experimental treatments where assumptions 

for parametric tests were met. When parametric assumptions were not met, we used the 

nonparametric Mann-Whitney and Kruskal-Wallis tests. All statistical analyses were performed 

using JMP10® statistical software.

7.4.2 Results

pH was maintained at target levels for each treatment (see Table 7-1 and Figure 7-8). For the 

group 1 coral experiments, pH varied significantly across all three treatments (Kruskal-Wallis test, 

H = 19.7481, p < 0.001). pH was 7.90 ± 0.05 for the ambient pH treatment, 7.79 ± 0.06 for the low 

pH treatment, and 7.67 ± 0.15 for the very low pH treatment. Pairwise comparisons reveal 

significant differences in pH between each treatment (see Table 7-2). For the group 2 coral 

experiments, pH varied significantly across all three treatments (Kruskal-Wallis test, H = 30.1405, 

p < 0.001). pH was 7.90 ± 0.08 for the ambient pH treatment, 7.78 ± 0.04 for the low pH treatment, 

and 7.67 ± 0.10 for the very low pH treatment. Pairwise comparisons reveal significant differences 

in pH between each treatment (see Table 7-3).

Table 7-1.

Experimental conditions (mean ± S.D.) of pH experiment

pH Ωarag

Treatment Group 1 Group 2 Group 1 Group 2

Ambient 7.90 ± 0.05 7.90 ± 0.08 1.47 ± 0.17 1.47 ± 0.23

Low 7.79 ± 0.06 7.78 ± 0.04 1.18 ± 0.18 1.11 ± 0.10

Very low 7.67 ± 0.15 7.67 ± 0.10 0.97 ± 0.39 0.92 ± 0.23
276

Figure 7-8. pH conditions (mean ± S.D.) for groups 1 and 2 for the pH experiments.

Table 7-2. 

Pairwise comparisons ( = 0.05) of pH among treatments in group 1 pH experiment

Ambient Low Very low

Ambient

Low 0.0004

Very low 0.0007 0.0034

Table 7-3. 

Pairwise comparisons ( = 0.05) of pH among treatments in group 2 pH experiment

Ambient Low Very low

Ambient

Low <0.0001

Very low <0.0001 0.0004

The target aragonite saturation state (Ωarag) was maintained for each treatment (see Figure 7-8 and 

Figure 7-9). For the group 1 coral experiments, Ωarag varied significantly across all three treatments 

(Kruskal-Wallis test, H = 20.4448, p < 0.001). Ωarag was 1.47 ± 0.17 in the ambient pH treatment, 

1.18 ± 0.18 in the low pH treatment, and 0.97 ± 0.39 in the very low pH treatment. Pairwise 

comparisons reveal significant differences in Ωarag between each treatment (see Table 7-4). For the 

group 2 coral experiments, Ωarag varied significantly across all three treatments (Kruskal-Wallis 

test, H = 30.859, p < 0.001). Ωarag was 1.47 ± 0.23 in the ambient pH treatment, 1.11 ± 0.10 in the 

low pH treatment, and 0.92 ± 0.23 in the very low pH treatment. Pairwise comparisons reveal 

significant differences in Ωarag between each treatment (see 

Table 7-5).

7.2

7.3

7.4

7.5

7.6

7.7

7.8

7.9

8

8.1

ambient low very low

pH

Treatment

Group 1 Group 2
277

Figure 7-9. Ωarag conditions (mean ± S.D.) for groups 1 and 2 for the pH experiments.

Table 7-4. 

Pairwise comparisons ( = 0.05) of Ωarag among treatments in group 1 pH experiment 

Ambient Low Very low

Ambient

Low 0.0002

Very low 0.0007 0.0036

Table 7-5. 

Pairwise comparisons ( = 0.05) of Ωarag among treatments in group 2 pH experiment 

Ambient Low Very low

Ambient

Low <0.0001

Very low <0.0001 0.0007

Average growth rates for L. pertusa group 1 corals were 0.011 ± 0.003, 0.006 ± 0.002, and -0.008 

± 0.03 %·d-1for ambient, low, and very low pH treatments, respectively (mean ± SE, Figure 7-10). 

Growth rate was not significantly different between the ambient and low pH treatments (MannWhitney U test, U = -1.31276, p = 0.1893). Growth rate was significantly affected (relative to 

ambient) in the very low pH treatment, where net dissolution was observed. Survivorship was 

100% across all treatments.
278

Figure 7-10. Growth of L. pertusa (over 7 days, mean ± S.E.) from the group 1 

pH experiments.

Average growth rates for L. pertusa group 2 corals were 0.039 ± 0.01, -0.012 ± 0.004, and -0.005 

± 0.003 %·d-1for ambient, low, and very low pH treatments, respectively (mean ± SE, Figure 

7-11). Growth rate was significantly affected (relative to ambient) in both the low and very low 

pH treatments, where net dissolution was observed. Growth rate was not significantly different 

between the low and very low pH treatments (Mann-Whitney U test, U = -0.9977, p = 0.3184).

Survivorship was 100% across all treatments.

Figure 7-11. Growth of L. pertusa (over 7 days, mean ± S.E.) from the group 2 pH 

experiments.
279

Coral growth rates differed significantly between group 1 and group 2 in the ambient treatment 

(Mann-Whitney U test, U = -2.4679, p = 0.0136) and the low treatment (Mann-Whitney U test, U 

= 3.3082, p = 0.0009). In the very low treatment, both experimental groups responded similarly 

(Mann-Whitney U test, U = -0.4726, p = 0.6365) by undergoing net dissolution (Figure 7-12). No 

tank effects were observed in any treatment (see Table 7-6). To constrain the critical threshold for 

calcification to occur beyond the a priori observations from the pH treatments, a linear regression 

of calcification of each coral to the measured pH and aragonite saturation state of each tank was 

performed. Results from this analysis show a critical pH of 7.73 (Figure 7-13) and aragonite 

saturation state of 1.06 (Figure 7-14) for net calcification to occur. 

.

Figure 7-12. Growth of L. pertusa (over 7 days, mean ± S.E.) from both groups 1 and 2 for the 

pH experiment.

Table 7-6. 

Results from Kruskal-Wallis tests ( = 0.05) on tank effects (differences in growth rate among 

tanks) in pH experiment

H p

Treatment Group 1 Group 2 Group 1 Group 2

Ambient 0.6944 0.5556 0.7066 0.7575

Low 0.2222 0.0278 0.8948 0.9862

Very low 5.1389 0.2222 0.0766 0.8948

-0.02

-0.01

0

0.01

0.02

0.03

0.04

0.05

0.06

ambient low very low

Net Calcification (%·d

-1

)

Treatment

Group 1 Group 2
280

Figure 7-13. Linear regression of L. pertusa growth to measured pH (over 7 days, mean ± S.E.) 

from both groups 1 and 2 for the pH experiment.

Figure 7-14. Linear regression of L. pertusa growth to measured aragonite saturation states 

(over 7 days, mean ± S.E.) from both groups 1 and 2 for the pH experiment.

y = 0.0986x - 0.7621

R2 = 0.2385

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

7.55 7.6 7.65 7.7 7.75 7.8 7.85 7.9 7.95

Net Calcification (%·d

-1

)

Measured pH

y = 0.0431x - 0.0458

R2 = 0.2526

-0.06

-0.04

-0.02

0

0.02

0.04

0.06

0.08

0.1

0.6 0.8 1 1.2 1.4 1.6

Net Calcification (%·d

-1

)

Measured Aragonite Saturation State
281

7.4.3 Discussion

Mortality due to pH stress has not been reported in the literature. In fact, acidification experiments 

over 12 months resulted in no mortality in the scleractinian species Oculina patagonica and 

Madracis pharencis; however, complete dissolution of the skeleton was observed in both species 

(Fine and Tchernov 2007). This implies that low pH may not necessarily contribute directly to 

mortality in scleractinian corals including L. pertusa, but may subject the corals to increased 

exposure to predators such as the gastropod Coralliophila sp. 

Our growth rate results from the ambient pH treatments agree well with published data for L. 

pertusa from the North Atlantic Ocean (Maier et al. 2009) and the Mediterranean Sea (Orejas et 

al. 2011, Form and Riebesell 2012, Maier et al. 2012). The growth rates between the two groups 

were significantly different at ambient conditions, and this difference may be attributed to the 

biological variation between the two groups. Furthermore, variability in L. pertusa growth rate has 

been reported in recent papers (Maier et al. 2009, Form andRiebesell 2012, Maier et al. 2012). 

Factors such as polyp rank (i.e. age) and size are recognized as major contributors to coral growth 

rate, with younger, higher ranked polyps growing faster than older polyps (Mortensen 2001, 

Brooke and Young 2009). While both groups in our experiment consisted of similarly-sized coral 

nubbins, no data is available on polyp age. 

The results from this set of experiments suggest a complex set of responses to ocean acidification 

in L. pertusa from the GoM. Perhaps the most striking result in this set of experiments is the 

disparate response of the two groups in the low pH (7.75) treatment. While the two groups did not 

experience statistically significant different conditions in pH or aragonite saturation state, mean 

pH and mean Ωarag were slightly lower (by 0.1 pH units and 0.08 in Ωarag) in the group 2 treatments 

(Figure 7-11 and Figure 7-12, Table 7-1). These slight differences, though not statistically 

significant, may be biologically relevant to calcification in L. pertusa. 

The difference in responses may also be attributed to the genotypic variation of the two 

experimental groups. Variation among responses to ocean acidification with respect to genotype 

has also been observed in bryozoans (Pistevos et al. 2011), oysters (Parker et al. 2012), and 

coccolithophores (Langer et al. 2009). Recently, Schaum et al. (2013) found that geographic 

location and life history (i.e. ecotype) are vital contributors to plastic responses to ocean 

acidification in picoplankton. Since all coral specimens used in our pH treatments were from the 

same geographic location (VK906), it is likely that genotype played a larger role than ecotype in 

this experiment.

Thresholds for calcification in a variety of calcifying species often do not often coincide with an 

aragonite saturation state equal to 1.0. For example, various studies in shallow-water corals 

identify the threshold for calcification to occur at 2.0 (reviewed in Doney et al. 2009). Because L. 

pertusa is most often observed at in situ aragonite saturation states significantly below 2.0 (Form 

and Riebesell 2012, Lunden et al. 2013), its threshold for calcification must fall under its observed 

environmental range. The present study identifies a calcification threshold of 1.06, significantly 

lower than the threshold observed in shallow-water taxa. Form and Riebesell (2012) observed 

positive net calcification at an aragonite saturation state of 0.93 in a long-term study, suggesting 

acclimation to reductions in aragonite saturation state; however, the samples used in this study 

come from only two biological replicates. In the present study, one L. pertusa genet sustained net 
282

positive calcification at an aragonite saturation state of 0.75. While L. pertusa may in fact be able 

to acclimate to ocean acidification, it is not clear if the results obtained in Form and Riebesell 

(2012) are due entirely to acclimation or to an as-yet-unidentified mechanism, potentially under 

genetic control, that confers resistance to ocean acidification. Results from a boron systematics 

study show L. pertusa’s capability to up-regulate pH and aragonite saturation state at the 

calcification site (McCulloch et al. 2012); however, it is unclear if this mechanism applies 

universally to L. pertusa individuals across a range of populations. Future work should further 

investigate the role of genetic variability to ocean acidification responses. 

7.5 TEMPERATURE EXPERIMENTS

7.5.1 Methods

7.5.1.1 Experimental Design and Setup

Each experiment was conducted in a constant-temperature room at TU. Three 20 gallon aquaria 

(“tall” type: 24" x 13" x 17") with individual filtration units (AquaClear 30) and pH controllers 

(Pinpoint®, American Marine Inc.) were used for each experiment (Figure 7-6). Three individual 

coral nubbins of unique genotype were randomly assigned to each tank for a total of nine nubbins 

per treatment. Each experiment lasted for a total of fifteen days, with an initial eight-day 

conditioning period to allow the corals to acclimate to the tank conditions. Growth was measured 

between days eight and fifteen to obtain a daily growth rate. Mortality was measured daily and at 

the conclusion of each treatment. 

The following temperature experiments were conducted: 8, 10, 12, 14, 16°C

Methods for seawater analyses, survivorship, and growth measurements are identical to those 

described above for the pH experiments.

7.5.2 Results and Discussion

Temperature was maintained at target levels for each treatment (see Table 7-7 and Figure 7-15). 

Temperature was significantly different across all treatments (Kruskal-Wallis test, H = 92.1309, p

< 0.001). Pairwise comparisons revealed significant differences in temperature between each 

treatment (see Table 7-8). In the 16°C experiment, pH was significantly higher than all other 

temperature treatments (Figure 7-15, Kruskal-Wallis test, H = 10.6864, p = 0.0303). Ωarag varied 

significantly among treatments (Figure 7-17, Kruskal-Wallis test, H = 63.5289, p < 0.0001) but 

was statistically similar between the 8°C and 10°C experiments (Mann-Whitney test, U = 0.02819, 

p = 0.9775). 
283

Table 7-7. 

Experimental conditions (mean ± s.d.) of temperature experiment

Treatment (oC) Temperature (oC) pH Ωarag

8 8.36 ± 0.23 7.92 ± 0.04 1.53 ± 0.14

10 9.91 ± 0.52 7.92 ± 0.04 1.54 ± 0.12

12 11.93 ± 0.28 7.89 ± 0.07 1.68 ± 0.21

14 14.02 ± 0.29 7.93 ± 0.03 1.92 ± 0.14

16 16.03 ± 0.48 7.95 ± 0.04 2.08 ± 0.18

Figure 7-15. Temperature conditions (mean ± s.d.) for the temperature experiments.

Table 7-8. 

Pairwise comparisons ( = 0.05) of temperature among treatments in the temperature experiment

8 10 12 14 16

8

10 <0.0001

12 <0.0001 <0.0001

14 <0.0001 <0.0001 <0.0001

16 <0.0001 <0.0001 <0.0001 <0.0001

0

2

4

6

8

10

12

14

16

18

8 10 12 14 16

Temperature (°C)

Treatment
284

Figure 7-16. pH conditions (mean ± s.d.) for the temperature experiments.

Figure 7-17. Ωarag conditions (mean ± s.d.) for the temperature experiments.

Cumulative survivorship of L. pertusa differed significantly among temperature regimes (Figure 

7-18, Kruskal-Wallis test, H = 33.9737, p < 0.0001) after 8 days at each treatment. Cumulative 

survivorship was 100% in the control treatment (8°C) and decreased in each successive treatment. 

At 10°C, cumulative survivorship was 86.73 ± 6.21% (mean ± SE, n = 9). At 12°C, cumulative 

survivorship was 69.88 ± 6.13% (mean ± SE, n = 9). At 14°C, cumulative survivorship was 53.58

± 8.52% (mean ± SE, n = 9). All corals experienced 100% mortality during the recovery period 

between the 14°C and 16°C experiments. Because of this, a new set of experimental corals was 

used for the 16°C experiment. Percent survivorship was 0% in the 16°C treatment. 

7.7

7.75

7.8

7.85

7.9

7.95

8

8 10 12 14 16

pH

Treatment

0

0.5

1

1.5

2

2.5

8 10 12 14 16

Ωarag

Treatment
285

Figure 7-18. Cumulative survivorship of L. pertusa (over 7 days, 

mean ± S.E.) from the temperature experiments.

Average L. pertusa growth rates were 0.002 ± 0.002, -0.012 ± 0.009, 0.0002 ± 0.007, 0.002 ± 

0.003, and -0.006 ± 0.005 %·d-1for the 8°C, 10°C, 12°C, 14°C, and 16°C experiment, respectively. 

Relative to the control (8°C), growth rate was significantly decreased at 10°C (Mann-Whitney test, 

U = -2.1529, p = 0.0313) and 16°C (Mann-Whitney test, U = -1.9726, p = 0.0485). No tank effects 

were observed in any treatment (see Table 7-9).

Table 7-9. 

Results from Kruskal-Wallis tests ( = 0.05) on tank effects (differences in growth rate among 

tanks) in temperature experiment

Treatment (°C) H p

8 1.444 0.4857

10 0.4722 0.7897

12 1.1111 0.5738

14 2.25 0.3247

16 1.0667 0.5866

H = variance of the ranks among groups; p = probability of getting a particular value of H by chance

Previous work in L. pertusa from the GoM shows that the upper mortality limit is approximately 

15°C (Brooke et al. 2013), and our data support these findings. While Brooke et al. (2013) found 

that exposure at 15°C resulted in ~20% mortality in L. pertusa, our data show that prolonged 

exposure at 10°C, 12°C, and 14°C results in pronounced mortality (see Figure 7-18). These effects 

may be due to the corals prolonged exposure to 8°C in the maintenance tanks, and these 

observations may be an effect of short-term thermal stress in animals acclimated to relatively stable 

conditions. However, all corals suffered complete mortality during the recovery period between 

the 14°C and 16°C experiments, resulting in a completely new set of corals being used for the 

16°C experiment.

As of this study, results showing temperature effects on cold-water coral growth are completely 

absent from the literature. Our data show that L. pertusa significantly decreases its growth rate 

0

10

20

30

40

50

60

70

80

90

100

8 10 12 14 16

Percent Survivorship 

(Cumulative)

Treatment
286

when exposed to temperature stress at 10°C and 16°C. However, growth rate gradually approaches 

the control (8°C) at 12°C and at 14°C. It is possible that an initial stress of 10°C was sufficient to 

induce the drastic reduction in growth rate observed here; however, increases in temperature are 

related to increases in Ωarag (Figure 7-17), and the growth observed at 12°C and 14°C may reflect 

these increases. Since all corals subsequently died during the recovery between the 14°C and 16°C 

experiments (described above), a new set of corals was used for the 16°C experiment, all of which 

exhibited net dissolution (Figure 7-19) and 0% survivorship at the conclusion of the experiment 

(Figure 7-18). The decrease in calcification may be attributed to an initial stress response by the 

corals, similar to the response observed at 10°C (Figure 7-19). 

Figure 7-19. Growth of L. pertusa (over 7 days, mean ± S.E.) 

from the temperature experiment.

7.6 DISSOLVED OXYGEN EXPERIMENTS

7.6.1 Methods

7.6.1.1 Experimental Design and Setup

Each experiment was conducted in a constant-temperature room at TU. Three 20 gallon aquaria 

(“tall” type: 24" x 13" x 17") with individual filtration units (AquaClear 30) and pH controllers 

(Pinpoint®, American Marine Inc.) were used for each experiment (Figure 7-6). Three individual 

coral nubbins of unique genotype were randomly assigned to each tank for a total of nine nubbins 

per treatment. Each experiment lasted for a total of fifteen days, with an initial eight-day 

conditioning period to allow the corals to acclimate to the tank conditions. Growth was measured 

between days eight and fifteen to obtain a daily growth rate. Mortality was measured daily and at 

the conclusion of each treatment. 

The following dissolved oxygen experiments were conducted: high (5 mL·L-1), middle (3 mL·L1

), low (1 mL·L-1). 

Methods for seawater analyses and survivorship measurements are identical to those described 

above in the pH experiments.

-0.025

-0.02

-0.015

-0.01

-0.005

0

0.005

0.01

8 10 12 14 16

Net Calcification (%·d

-1

)

Temperature (°C )
287

7.6.2 Results and Discussion

Dissolved oxygen was maintained at target levels for each treatment. Average DO concentration 

was 5.32 ± 0.28 mL·L-1, 2.92 ± 0.21 mL·L-1, and 1.57 ± 0.28 mL·L-1for the hyperoxic, normoxic, 

and hypoxic treatments, respectively (Figure 7-20). DO was significantly different across all 

treatments (Kruskal-Wallis test, H = 474.75, p < 0.001). Pairwise comparisons revealed significant 

differences in DO between each treatment (see Table 7-10).

Figure 7-20. Dissolved oxygen conditions (mean ± S.D.) for the 

dissolved oxygen experiments.

Table 7-10. 

Pairwise comparisons ( = 0.05) of dissolved oxygen among treatments in the dissolved oxygen 

experiment

Hyperoxic Normoxic Hypoxic

Hyperoxic

Normoxic <0.0001

Hypoxic <0.0001 <0.0001

Survivorship of L. pertusa was 100% at both the hyperoxic and normoxic treatments. However, 

survivorship decreased to 0% in the hypoxic treatment (DO = 1.57 ± 0.28 mL·L-1, Figure 7-21). 

No mortality was observed in between treatments.

0

1

2

3

4

5

6

high middle low

Dissolved Oxygen (mL·L-1

)

Treatment
288

Figure 7-21. Percent survivorship of L. pertusa (over 7 days, mean ± 

S.E.) from the dissolved oxygen experiments.

Results from 2008, 2009, and 2010 cruises show spatial and temporal variability in dissolved 

oxygen at L. pertusa sites in the GoM, with a minimum oxygen concentration of 1.5 mL·L-1

observed at VK906 in 2009. This suggests that, at a minimum, L. pertusa at VK906 is episodically 

exposed to hypoxic conditions; however, these exposures likely do not last long enough to inflict 

significant mortality. Previous work has explored the metabolic tolerance of L. pertusa to various 

oxygen concentrations, and found that L. pertusa is unable to maintain aerobic respiration at 

oxygen concentrations less than 3.26 mL·L-1at 9°C (Dodds et al. 2007). However, this work was 

performed on samples from the Northeast Atlantic, where the mean local oxygen concentration 

was 6.10 mL·L-1. Oxygen concentrations ranging from 2.6-3.2 mL·L-1have been reported from 

the GoM surrounding L. pertusa mounds (Schroeder 2002, Davies et al. 2010), and field results 

from this project show dissolved oxygen reaching a minimum of 1.5 mL·L-1near L. pertusa

mounds. These results suggest a lower oxygen threshold for L. pertusa aerobic respiration in the 

GoM; however, our mortality data show that long-term exposure (8 days) to sustained hypoxic 

conditions near 1.57 mL·L-1results in complete mortality. While L. pertusa is able to employ 

anaerobic respiration for periods up to 96 hours (Dodds et al. 2007), our data suggest that this 

strategy is not sufficient to maintain energetic requirements over longer periods. Future 

experiments should utilize respirometry to study the oxygen demands of GoM L. pertusa, and 

potentially will be able to resolve the maximum timeframe that L. pertusa is able to utilize 

anaerobic respiration to maintain physiological processes.

Growth studies under the dissolved oxygen regimes were complicated by the elevation in pH and 

aragonite saturation state due to the injection of nitrogen gas (Figure 7-22). Nitrogen gas is 

commonly employed in dissolved oxygen manipulations as it removes oxygen from the seawater; 

however, nitrogen also removes dissolved carbon dioxide, resulting in an elevation in pH and 

aragonite saturation state. At elevated saturation states, abiogenic calcium carbonate can 

precipitate onto the coral skeleton. In fact, Holcomb et al. (2009) observed precipitation of 

abiogenic calcium carbonate at Ωarag near 5.0. The Ωarag of the dissolved oxygen experiments 

ranged from 3.23-4.88 (Figure 7-22), with the highest Ωarag observed in the low dissolved oxygen 

0

10

20

30

40

50

60

70

80

90

100

high middle low

Percent Survivorship

(Cumulative)

Treatment
289

treatment where nitrogen injection was most pronounced. The abiogenic formation of calcium 

carbonate due to the elevation in Ωarag inhibited our interpretation of the effects of dissolved 

oxygen changes on growth in L. pertusa. 

Figure 7-22. Ωarag conditions (mean ± S.D.) for the dissolved oxygen

experiments.

0

1

2

3

4

5

6

7

high middle low

Ωarag

Treatment
290

8 BIOLOGICAL COMMUNITIES ON ARTIFICIAL SUBSTRATES, WITH 

EMPHASIS ON LOPHELIA PERTUSA.

8.1 INTRODUCTION:

This component of the project was fine tuned to an emphasis on Lophelia pertusa occurrence and 

growth rates on artificial substrates due to a number of factors that limited our access to appropriate 

imagery and samples for a more comprehensive study of all of the platforms. 

Images from a total of seven platforms and one subsea installation were utilized for this aspect of 

the project. The data that could be derived from the imagery varied greatly depending on the 

quality of the imagery and the associated data we were able to obtain for that imagery. In many 

cases, the imagery supplied by the platform operators was not of sufficient quality to identify most 

species with certainty, and in some cases even identifying “coral” was problematic. However, the 

bright white color of L. pertusa and the fact that it was usually the only moderate-sized colonial 

coral on the platforms facilitated aspects such as determination of the density of colonies. Imagery 

that was appropriate for fish surveys was extremely limited and was not appropriate for collection 

of data on coral sizes and densities on the platforms because fish surveys required a wide field of 

view while coral surveys required close-up imagery of the structural members of the platform. 

Because much of the imagery was collected without the use of parallel lasers for scale, it was 

critical to know the diameter of the members in the images and this data was often not possible to 

obtain from the operators of the platforms, because the exact member being surveyed was not 

always known. In these cases, we were able to constrain the diameters of the structural members 

in question to within an error of about 50%. We received platform inspection videos from 

platform operators for Pompano, Petronius, and Neptune that included portions of video of 

sufficient quality and with accompanying data appropriate for this study. We also obtained 

inspection video from the Baldpate platform, which was not appropriate for most of our work on 

Lophelia pertusa. This was appropriate for a qualitative fish survey, however, and that data are 

reported below. 

From July 12 – 24, 2012 the Kracken ROV was used from the RV Brooks McCall specifically to 

survey and sample platforms for this study. A combination of weather, ROV capabilities and 

problems, and concerns with entanglement due to incomplete information from platform operators 

combined to compromise this research effort. As a result, only a few collections were made, and 

no community collections were accomplished. When it became apparent that the amount of 

imagery we could collect would be quite limited, the decision was made to concentrate on imagery 

appropriate to quantify L. pertusa and other colonial coral occurrence and growth rates, 

recognizing that this would preclude collection of data on fish occurrence. Imagery was collected 

from Jolliet, Cognac, and Ram Powell, as well as the Zinc subsea installation before the cruise was 

terminated due to loss of the ROV.

Although we have limited data above about 150 m depth, it was noted that in general all platforms 

had a zone of extensive biological coverage near the air-water interface that gradually transitions 

into a zone of relatively sparse large fauna at around 100 m depth. This zone transitions back to a 

zone of encrustation with larger attached fauna starting with anemones and progressing to L. 
291

pertusa growth at about 200 m. Near the sea floor (or below the depth of occurrence of L. pertusa), 

there is a transition to a zone with no L pertusa but abundant anemones. The depth of these zones 

shifts slightly with each platform and may be related to the age and water depth of the platform. 

Though L. pertusa and large anemones do co-exist at the upper and lower ends of L. pertusa depth 

range, they do not co-exist in abundance where either taxa is present at high densities. Very few 

non-L. pertusa corals were observed on the platforms within the depth range focused on for this 

study (below 175 m) with the exception of Cognac.

8.2 OVERVIEW OF EACH PLATFORM STUDIED:

8.2.1 Neptune

Water depth – 1,952 ft (595 m)

Installation date – 1996

Complex ID 24235

Lease block – VK826

Structure type – Spar

We received video from a rig inspection conducted from May 9-12, 2011 that contained 168 1⁄2-

hour video files, 28 of which were of suitable quality for our use. Each file was a scan at constant 

heading of one structural member, or two parallel members, from varying distances. Potentially 

usable scanned structural members included wires, pile chains, risers, export risers and umbilicals. 

Video observations began at 153 m depth. There were no large attached cnidarians between 150 

and 300 m, although small solitary orange cnidarians and what appeared to be small hydroid 

colonies were present in this depth range. L. pertusa was the only colonial coral seen on Neptune 

and was present from 262 to 614 m depth. Fly trap and other large anemones were present on 

many structural members below approximately 300 m depth and became abundant below 550 m 

depth as L. pertusa density decreased. 

8.2.2 Pompano 

Water depth – 1,312 ft (400 m)

Installation date – 1994

Complex ID 24130

Lease Block – VK989

Structure Type – Solid

Three separate video collections were received and used for analyses of Pompano communities: 

an inspection video collection taken November 8, 2008; a video collection obtained at our request 

during an inspection survey on July 14, 2009; and an inspection video collection from June 2-6, 

2011. Coral samples collected in 2009 were also supplied to USGS collaborator, Cheryl Morrison. 

The first two video collections were standard definition videos and the 2011 video was high 

definition (HD). 
292

Eight digital versatile discs (DVDs) were supplied by the platform operators from the 2008 survey 

and 5 of these included video suitable for this study. Each DVD contained approximately 1 hour 

45 minutes of video and there was a total of 5 hours of useable footage from this set. This 

inspection video was of the riser array which was a 5-pipe-by-8-pipe grid of evenly spaced 76.2 

cm (30 in.) and 91.4 cm (36 in.) diameter structures running vertically from the sea floor to the 

surface. This grid was periodically intersected by horizontal members and other support structures. 

The video collection included interrupted vertical scans of single risers from shallow to deep water 

as well as horizontal scans of one side of the array where the video moves from one riser to another

while maintaining the same depth and heading. Because of the intersecting horizontal members, 

and limitations of the ROV due to its umbilical, there are no continuous scans of a single riser from 

152 m (500 ft) to the sea floor 400 m (1,312 ft). Density estimates reported below were calculated

by “piecing” together data from numerous scans of various risers. 

The video collection from 2009 looked specifically at L. pertusa occurrence on the structure. The 

primary focus of the video is continuous scans at constant heading of two ~320 cm diameter legs 

with a few minutes of additional structure visible. Total video time for this collection is 2.5 hours.

The most recent video collection was from a 2011 HD video inspection of the entire jacket of 

Pompano from the surface to the sea floor, but does not include scans of risers. Large leg structures 

and smaller vertical, horizontal, and diagonal members of varying sizes and at different headings 

were inspected. This collection of video was organized by scans of individual structural

components and contained 338 video files that ranged from 1-15 min in length and each contained 

a complete scan of one to four structural components. Components are units of structure defined 

by the dive company operating the inspection; most often, these components are either structure 

nodes or lengths of structure between nodes. Components other than members are not used in this 

analysis. Scans are pieced together for an analysis of coral density with increasing depth.

Data collection began at 122 m depth. Small anemones and hydroids are visible but scarce until 

they become more abundant through the interval to 183 m where fly-trap and other large anemones 

begin to appear. Four non-L. pertusa (unidentified) colonial corals (Figure 8-1) were observed in 

the 2008 video collection between 183 m and 366 m; these corals were not near each other. Orange 

L. pertusa were present on Pompano. In the 2011 video, numerous white globular shaped corals

or sponges (Figure 8-2) were found at approximately 137 – 183 m (450-600 ft). A small school 

of amberjacks, Seriola dumerili, was present at 170 m depth (Figure 8-3). Fly-trap anemones were 

abundant and constituted the most predominate, large identifiable fauna on the base of the 

structure. 
293

Figure 8-1. An apparent colonial coral that is not L. pertusa is visible on the left edge of 

this structural member on Pompano at 336 m depth. Four “corals” resembling 

this were seen at Pompano.

Figure 8-2. White globular coral or sponge from Pompano 5/24/2011 survey at a 

depth of 180 m (590 ft).
294

Figure 8-3. Small school of amberjacks, Seriola dumerili, seen on the 2011 survey 

of Pompano at 178 m depth.

8.2.3 Petronius 

Water depth – 1,771 ft (540 m)

Installation date – late 1998 (top and bottom sections), June 2000 (24 inch risers) 

Complex ID - 70012

Lease block – VK786

Structure type – Compliant Tower

We received an inspection video collection taken October 10 to 12, 2008 for the Petronius 

platform. Approximately 41 hours of video on 6 disks were screened, yielding approximately 20 

hours of usable video. The videos contain broken scans of various structures at multiple headings,

including large ~335 cm (132 inch) legs; smaller vertical, horizontal, and diagonal jacket members, 

and risers from the surface to the sea floor (540 m). The videos contain short scans of member or 

riser segments interrupted by other members or by breaks in camera focus on the structure that are 

“pieced” together for analysis of density with increasing depth.

The faunal progression for Petronius is very similar to that of Pompano, where there is a zone of 

little to no large fauna from about 60 m to 180 m depth. Large fauna, dominated by anemones, 
295

become gradually more abundant below this depth. The first L. pertusa was seen at 248 m and 

increased in abundance until approximately 450 m then persisted until about 10 m above the sea 

floor. Below this depth was a zone with extensive coverage of fly-trap anemones. 

The fallen South Platform, which resides on the sea floor nearby, is covered with anemones, but 

no visible L. pertusa or other colonial corals were present on this structure. 

8.2.4 Baldpate 

Water depth – 1,650 ft (503 m)

Installation date – 1998

Complex ID - 33039

Lease block – GB260

Structure type – Compliant Tower

We received one inspection video totaling 4.5 hours taken on September 27, 2008. An attempt to 

dive on Baldpate was made during the Brooks McCall cruise in 2012, but the dive was aborted 

soon after approaching the structure due to unanticipated obstructions on the platform. The 

presence of L. pertusa on the structure was confirmed but no other usable data were collected. 

The 2008 Baldpate survey was not adequate for L. pertusa density or growth analysis but did allow 

better survey of fish populations than other platform surveys even though the depth gauge only 

functioned intermittently. The survey started at 67 m depth and noted numerous reef-type fish 

associated with small sea fans and tubastraea colonies. Fish present above 125 m depth included 

french angelfish, rock hind, graysby, blue tang, gray triggerfish, bermuda chub, squirrelfish and 

reef butterfly fish. Fish density abundance decreased markedly and was almost absent by 126 m 

depth, although a squirrelfish, a reef butterfly, and a small roughtongue bass were noted at this 

depth. Sea fans were absent by 137 m and fish were very sparse below this depth. A few Anthiines 

were noted between 140 m and 240 m depth, but large attached inverts were very rare. A single 

roughtongue bass was seen at 241 m depth. The first L. pertusa were seen at 282 m and the first 

fly trap anemone at 308 m. L. pertusa remained relatively rare to 333 m and fish were almost 

completely absent. Brisingid starfish were first sighted at 310 m and became abundant down to 

about 360 m. Small L. pertusa appeared to become more abundant from this depth and were 

present until 5-10 m from the sea floor (about 500 m).

8.2.5 Jolliet 

Water depth – 1,781 ft (543 m)

Installation date – 1989

Complex ID 23583

Protraction Area – Green Canyon

Lease block – GC184

Operator name – MC Offshore

Structure type – Tension Leg Platform (TLP)/Template
296

The Jolliet platform was surveyed on July 17, 2012 using the Kraken ROV on the RV Brooks 

McCall. One and a half hours of usable video footage were collected during a single pass down 

one tendon of the structure from 35 m to 437 m depth. No biota clearly identifiable while colonial 

corals were observed from 35 m to 75 m, though small flora and fauna, and numerous fish, 

including schools of jack and chub, were present at this depth (Figure 8-4, Figure 8-5). Larger 

fauna, including some unidentifiable potential coral colonies and smaller unidentified cnidarians,

were present between 75 m and 110 m. From 110 m down to 235 m the faunal coverage decreased 

steadily; only small attached fauna was present and no identifiable corals were observed in this 

depth range. Starting at 235 m, anemones, zooanthids and hydroids began to increase in abundance 

until about 275 m. Attached fauna was again sparse between 275 and 300 m depth. The first L. 

pertusa colony was seen at 294 m and L. pertusa, larger anemones and other solitary cnidarians 

increased in abundance from about 300 m to 437 m where L. pertusa and fly-trap anemones were 

abundant. The base of this structure was not imaged. No identifiable corals other than L. pertusa

were observed on this structure. Non-white L. pertusa were observed on this structure. 

Figure 8-4. School of jacks (species level ID not possible from image) imaged at 

37 m depth on platform Jolliet.
297

Figure 8-5. School of chub, Kyphosus sectatrix, at 38 m depth on platform Jolliet.

8.2.6 Ram-Powell 

Water depth – 3,264 ft (995 m)

Installation date – 1997

Complex ID 24229

Lease block – VK956

Structure type – TLP/Template

Ram Powell was surveyed on July 20, 2012 using the Kraken ROV on the RV Brooks McCall. 

Almost five and a half hours of video footage, including 3 hours of footage suitable for analysis, 

were collected during a single pass up one tendon of the structure from the sea floor at 995 m to 

200 m, when the survey was terminated because of time constraints. Ram Powell was the only 

structure surveyed that extended past the known depth range for L. pertusa, so was the only 

structure where robust data on deepest depth of occurrence, and relations between depth and 

density and growth rate were obtained. Large attached fauna were almost completely absent from 

200 m to 275 m depth. Large anemones were first seen at 275 m depth and were sparse down to 

about 350 m. Below this depth, both anemones and L. pertusa became increasingly abundant, 

along with smaller solitary cnidarians. Below 600 m, L. pertusa and the larger anemones persisted 

but abundance decreased with depth, and smaller cnidarians became quite rare. The last L. pertusa

was noted at 801 m, and below this depth visible attached megafauna were very sparse. One L. 

pertusa colony was found on the sea floor near the base of the structure (Figure 8-6); however this 

colony had dead or dying polyps on the ends of several branches and was interpreted as most likely 
298

representing a dying fragment that had been dislodged from the structure above. No fish were 

observed during the scan of the tendon. 

Figure 8-6. L. pertusa on the sea floor under Platform Ram Powell at a depth of 

1,010 m. 

8.2.7 Cognac 

Water depth – 1,033 ft (315 m)

Installation date – 1978

Complex ID 22178

Lease block – MC194

Structure type – Solid

Cognac was surveyed on July 21, 2012 using the Kraken ROV on the RV Brooks McCall. One 

hour and 45 min of video footage suitable for analysis was collected during a single pass up one 

leg of the structure from the sea floor to 165 m depth. Cognac was the oldest structure surveyed,

and several aspects of the coral communities there probably reflect this: 

There were several areas on Cognac where the L. pertusa growth had reached the thicket stage, 

and it was not possible to differentiate individual colonies. 

Although, like the other structures, there was no L. pertusa attached to the basal 5-10 m of this 

structure, there were abundant living (and apparently healthy) L. pertusa on the sea floor near the 
299

base (Figure 8-7). This likely reflects survival of some fragments that have been dislodged from 

the structure above. 

Another reflection of the age of this structure was the significantly increased presence of what 

appear to be non-L. pertusa colonial corals (Figure 8-8 and Figure 8-9), similar in appearance to 

the few seen on Pompano.

Finally, unlike the other structures surveyed, no large anemones were present in areas of highest 

L. pertusa abundance, perhaps reflecting out-competition by L. pertusa.

No data was collected at depths above 165 m. No large attached fauna was present between 165 

m and 180 m. Between 180 m and 250 m, a non L. pertusa colonial coral was present with a peak 

in abundance near the bottom of this range. L. pertusa was present between 218 m and 320 m. No 

large anemones were present above 280 m nor were they present at peak L. pertusa depths (260 m 

to 325 m). There was no L. pertusa on the base of Cognac (within about 5-8 m of the sea floor), 

but unlike like other structures, L. pertusa were observed on the sea floor near the base of the 

structure (Figure 8-7). Non- white L. pertusa were observed on this structure.

Figure 8-7. L. pertusa colonies growing on the sea floor near the base of Platform Cognac at depth 

of 322 m.
300

Figure 8-8. Close-up of what appears to be a non-L. pertusa colonial coral on Platform

Cognac at a depth 234 m.

Figure 8-9. Numerous “non-L. pertusa colonial corals” on Platform Cognac at a depth of 328 m.
301

8.2.8 Zinc Subsea Installation

Water depth – approximately 1,500 ft (450 m)

Installation date - 1991

Protraction Area – Mississippi Canyon

Lease block – MC355

Operator name- Exxon Mobil

Structure type – Subsea 

The Zinc subsea installation was surveyed on July 19, 2012 using the Kraken ROV on the RV 

Brooks McCall. No observable megafauna was found at the base of this installation. There was 

heavy sedimentation around the base of the main installation and bare steel was often visible on 

basal parts of the main installation. About 7 m above the sea floor, on turrets near the top of the 

main installation there were scattered small L. pertusa colonies, zoanthids and small anemones 

(Figure 8-10, Figure 8-11). Most imagery was collected from an abandoned flow-tube test pile 

located several meters away from the main installation. Similar to the other installations, 

anemones, but no L. pertusa, were present on the basal parts of the test pile (Figure 8-12). 

However, L. pertusa were abundant higher up on this structure. This test pile was approximately 

15 m in height, including four corner protrusions from the elevated flow-tube platform. Fish, 

including numerous Atlantic roughy, were observed around and inside of the platform area of the 

abandoned test pile (Figure 8-13). Large fly-trap and other anemones were also visible on this test 

pile, but no corals other than L. pertusa were observed. Squat lobsters, crabs, ctenophores, and 

copepods were numerous as well at the test pile. 

Figure 8-10. Flow-tube connection at Zinc installation with broken L. pertusa

approximately 7 m above the sea floor.
302

Figure 8-11. Fauna incrusted flow-tube connection about 7 m above the sea floor at the Zinc

installation.

Figure 8-12. Light cnidarian encrustation with no L. pertusa on base of the abandoned test pile 

near the Zinc installation (within 5 m of the sea floor).
303

Figure 8-13. Atlantic roughy, Hoplostethus occidentalis, among L. pertusa around the 

abandoned test-pile near the Zinc installation at 450 m depth.

8.3 GROWTH RATES, DENSITIES, AND DISTRIBUTION OF LOPHELIA PERTUSA ON 

ARTIFICIAL STRUCTURES IN THE GULF OF MEXICO 

(Excerpted from a manuscript of the same title authored by Elizabeth A. Larcom, Danielle 

McKean, and Charles Fisher, submitted to Deep Sea Research in April 2013)

8.3.1 Abstract

Using industry inspection video and ROV imaging, we examined Lophelia pertusa (Linnaeus

1758) on 10 artificial structures of known ages (9 to 103 years) in the northern GoM (GoM). Five 

different types of deep-water hydrocarbon installations with depths ranging from 320 m to 995 m, 

and three shipwrecks with depths ranging from approximately 530 m to 615 m were examined. 

Density, depth ranges, and growth rates of L. pertusa colonies were calculated from video and 

image analysis. L. pertusa colonies were present on all structures examined. Minimum calculated 

growth rates for the largest colonies ranged from 0.32 to 3.23 cm/year on the different structures. 

Colony density varied with structure type, age, and depth, with of the highest density between 503-

518 m on the single structure that spanned the entire depth range of occurrence of L. pertusa. L. 

pertusa on thinner and deeper, hydrocarbon structure types (spar and tension leg platforms) appear 
304

to have higher colonization rates as they support higher densities in less time. However, on 

average, colonies have slower growth rates on these structures than colonies on more massive, 

shallower hydrocarbon structure types (compliant and solid platforms). In general, the calculated 

minimum growth rates were higher on the hydrocarbon installations than on the shipwrecks, which 

were substantially older. A continuum of colony sizes was documented on all installations, 

suggesting multiple settlement events. L. pertusa thickets were observed on the oldest structures 

with most structural components covered by colonies of L. pertusa. The shallowest depth of L. 

pertusa observed was at 201 m and the deepest at 801 m, considerably expanding the known depth 

range of the species in the northern GoM. Brown, orange, and mottled morphotypes were 

documented for the first time in the GoM. All energy platforms examined for this study were 

colonized by L. pertusa and it is likely that most artificial surfaces in appropriate depths in the 

GoM will be as well.

8.3.2 Introduction

Though most recent literature has focused on natural L. pertusa reefs (Brooke and Schroeder, 

2007; Freiwald, 2002; Freiwald and Henrich, 1997; Roberts, et al., 2010; Rogers, 1999; Schroeder, 

2002; Sulak, 2008; Willson, 1979), L. pertusa growth on anthropogenic substrates such as sub-sea 

cables (Duncan, 1877; Wilson, 1979), oil and gas platforms (Bell and Smith, 1999; Gass and 

Roberts, 2006; Schroeder et al., 2005) and ship wrecks (Church et al., 2007; Roberts et al., 2003), 

is well documented.

There are numerous types of hydrocarbon drilling, production, and storage structures in the GoM 

that either have a surface component supported by long rigid members, buoyancy, or a 

combination of the two. Other types of installations are entirely sub-sea. All of these structures, 

as well as shipwrecks, can provide a substrate favorable for the settlement of a variety of 

invertebrate taxa and have the potential to provide habitat for L. pertusa settlement and growth.

Growth rates previously reported for L. pertusa vary widely. Growth rates determined for North 

Sea L. pertusa from depths < 300 m range from measurements of 2.6 mm/yr under laboratory 

conditions to in situ estimates of 20 – 25 mm/yr using stable and radio isotopic techniques 

(Freiwald and Henrich, 1997; Mikkelsen, et al., 1982; Mortensen and Rapp, 1998). Direct 

measurements of L. pertusa from the Mediterranean kept in aquaria had linear extension rates 

ranging from 15-17 mm/year (Orejas et al., 2007). In situ measurements using pieces of L. pertusa

stained on the surface with Alizarian Red and then deployed in their natural habitat in the GoM 

found average linear growth rates of 2.4 to 3.8 mm/year (Brooke and Young, 2009). The highest 

growth rates measured for L. pertusa are in the range of slower growing massive shallow-water 

scleractinian corals (Orejas et al., 2011) yet are considerably greater than most deep water 

antipatharian or gorgonian coral growth rates (Prouty et al., 2011; Roark et al., 2009). 

Growth rates for colonial corals on anthropogenic substrates can be constrained by dividing colony 

size by the amount of time the substrate has been available for colonization. Growth rates 

determined using this method for L. pertusa in the North Sea, where its maximum depth of 

occurrence is 132 m, range from 5 mm/year to 36 mm/year (Bell and Smith, 1999; Gass and 

Roberts, 2006; Roberts, 2002; Wilson, 1979). This method assumes the coral larvae settled and 

started growing immediately after the substrate was first available and therefore provides a 
305

minimum growth rate, as settlement is unlikely to occur instantly and will continue to occur as 

long as suitable substrate is available to competent larvae. Here we determine occurrence, growth 

rates, densities and distributions of L. pertusa colonies on oil and gas platforms, and on several 

ship wrecks, and examine how these parameters vary with depth and structure type in the GoM.

8.3.3 Methods

We examined Lophelia pertusa distribution and growth on 6 energy platforms of four different 

types, one sub-sea installation, and three shipwrecks in the Northern GoM (Table 8-1.

Structure characteristics. and L. pertusa occurrence and growth rates, Figure 8-14). The data used 

in this study was acquired from a combination of inspection videos provided by platform operators 

and imagery acquired specifically for this study. Industry supplied inspection video from three 

different platforms was used in this study: Platforms Pompano, Petronius, and Neptune, including 

video from two different years for Pompano and two different member types installed in different 

years for Petronius. In July 2012, we conducted a cruise specifically to acquire data on L. pertusa

distribution on energy platforms using the Research Vessel Brooks McCall and the ROV Kraken 

2 . Imagery was collected using a Kongsberg HD Video Camera and Canon PowerShot G11 10 

m pixel Digital Still camera. The shipwrecks were imaged in 2009 and 2010 from the ROV Jason

II, using an HD video camera. Both frame grabs from video and digital still images were used in 

our analyses.
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Table 8-1.

Structure characteristics. and L. pertusa occurrence and growth rates

Structure Location

(Lat., 

Long.)

Structure 

Type/

Structure 

Member(s) 

Surveyed

Age of 

Structure 

at Time of 

Imaging 

(years)

Approximate

Water Depth 

of Structure 

(m)

Depth of 

Range of 

Occurrence

(m)

Depth 

Interval of 

Highest 

Averaged 

Density

(m)

Highest 

Averaged 

Density 

(colonies/m2)

Number 

of 

Colonies 

Measured 

for 

Growth 

Rate

Min. Growth 

Rate of top 10% 

of Corals 

(cm/year)

Ave. ± 1 SD

Minimum 

Growth 

Rate 

(cm/year)

Petronius -87.8, 29.2 Compliant 

Tower/Risers 9 532 248 - 530 442-457 0.93 36 3.23 ± 0.18(n=4) 3.47

Petronius -87.8, 29.2 Compliant 

Tower/Legs 10 532 248 -530 411-427 1.31 N/A N/A N/A

Pompano

2008a -88.6, 29.0 Solid /Risers 14 400 218- 378 351-367 1.03 71 2.12 ± 0.14

(n=7) 2.32

Ram 

Powell -88.1, 29.0 Tension 

Leg/Leg 15 995 288-801 503-518 10.69 317 1.45 ± 0.16(n=32) 1.86

Neptune -88.0, 29.2 Spar/Risers 15 614 262-614 503-518 8.54 632 1.23 ± 0.19

(n=63) 1.78

Pompano

2011a -88.6, 29.0

Solid/Legs 

and Support 

Members

17 400 201-394 351-367 2.73 503 2.20 ± 0.20

(n= 50) 2.93

Jollietb

-91.5, 27.8 Tension 

Leg/Leg 23 524 294-unknown 411-427 N/A 239 1.22 ± 0.09(n=24) 1.53

Zinc -89.9, 28.6

Subsea 

Installation/ 

Conductor 

Support 

21 447 N/A N/A N/A 38 2.48 ± 0.35

(n=4) 3.00

Cognac -89.1, 28.8

Solid/Leg 

and Support 

Members

34 320

218 – 320 

(seafloor)c

325-260 Thickets 50 2.06 ± 0.15

(n=5) 2.30

GulfPenn -89.3, 28.5 Ship Wreck 66 ~550 N/A N/A Thickets 42 1.25 ± 0.08

(n=4) 1.36

GulfOil -89.8, 28.1 Ship Wreck 67 ~535 N/A N/A Thickets 9

1.12 ± 0.32

(n=9)

e 1.60

Green 

Lantern -90.1, 28.0 Ship Wreck 103-86d

 ~615 N/A N/A Thickets 7

0.36 ± 1.1

(89 years)

(n =7)e

 0.32 ± 0.9

(103 years)

0.53 

(89 years)

0.45

(103 years)
307

Figure 8-14. Location of platforms, shipwrecks, and sub-sea installation by lease block.

The video analysis software Studiocode 4.5.1 was used to log and classify the data acquired from 

the video survey. Studiocode allows the user to create unique, customizable “codes” (such as “L. 

pertusa present,” “horizontal structure,” “depth interval,” etc.) that are synced via a timeline to the 

video and frame grabs from the video, and can be accessed through an interactive database. 

Although only subsets of the entire video record were suitable for most measurements, the 

shallowest and deepest unambiguous depth of occurrence of L. pertusa was recorded for each 

structure.

Two different methods were used to estimate scale in the images. For the quantitative analyses 

from the industry supplied inspection video, only images with both sides of the structure member 

in the frame were used for analysis because the structure diameter was used for scale in these 

images. Scale for the images acquired during the July 2012 cruise and from the ship wrecks was 

acquired from a pair of forward-facing parallel lasers spaced 10 cm apart mounted in the plane of 

the video and aimed at the center of the structure member. Only colonies clearly attached to a 

vertical or horizontal structure member, where colony attachment point could be reasonably 

inferred, were used for measurements; colonies growing near pipe junctions, on projecting or 
308

irregular structures, or on closely adjoining structures were not used for any quantitative analyses. 

Colony area and growth rate measurements were taken from video screen shots or digital images 

using Adobe Photoshop CS3 or PixelStick 2.3 and converted from pixels to cm using scale 

determined as described above.

In order to avoid overestimating growth rates, all measurements for growth determinations were 

taken from a clear attachment point on the anthropogenic structure to the furthest apparent 

extension of that colony from that attachment surface (df in Figure 8-15a). This method always 

provided a conservative measure for the maximum extension of the colony from its point of 

attachment, even if the colony was partially obscured by the structure or had fused with other 

colonies. Growth rate (cm/year) was calculated by dividing df by the time that the anthropogenic 

substrate had been available for colonization. Coral measurements that yielded the highest growth 

rates in each data set were re-measured and checked by an independent observer.

Two sets of data that could be obtained from all corals present in suitable quality video of the 

energy platforms were used for analysis of L. pertusa depth distribution patterns; density of 

colonies and colony area. For density measurements, only L. pertusa with attachment points on 

the side of a vertical structural member facing the ROV were used; L. pertusa, where portions of 

a colony were seen “peeking” out from the far side of the structure, were not counted for density. 

Density was calculated by dividing the number of colonies within a 15.25 m (50 ft) depth interval 

by the surface area of half the face of a cylindrical structure (πrh) where r is the radius of the 

structure and h is the length of the structure member or usable video within a given depth interval. 

Some portions of video unsuitable for colony size or measurements for calculation of growth rate 

due to video quality were still used for density calculations when L. pertusa colonies could be 

clearly identified.

For colony area measurements, only colonies that were clearly visible and appeared to be single 

colonies were used. Colonies with shapes that suggested two or more colonies had grown together 

were not measured. For colonies on the face of a structural member, area was estimated from 

measurement of two diameters: one along the colony’s longest axis (d1) and one perpendicular to 

this (d2) using the equation for an ellipse where area =(d1/2) *(d2/2) *π (Figure 8-15). Colony area 

for L. pertusa visible in profile on the edge of the structures was calculated using the equation for 

a circle, where area = (d1/2) 2 * π, and d1 was the colony diameter parallel to the structure (Figure 

8-15).
309

Figure 8-15. Diagram of the measuring protocol for L. pertusa colonies. For the determination 

of growth rates, maximum extension from an attachment point, such as shown for 

colony “a”, is used. The dashed line is used to establish a point of colony contact with 

the structure. The light line (df) represents the distance used to estimate minimum 

linear colony growth rates. The dark line (d1) represents the measurement of colony 

diameter, which, in conjunction with the linear extension measurement, is used to 

calculate minimum colony area for corals captured in profile. To determine colony 

area for corals on the surface of the structures, two diameters are measured (see coral 

“b”); one at the widest point of the colony (dark line, d1) and another perpendicular to 

the other, mid point on line d1 (light line, d2). The two lasers in the image are 10 cm 

apart and used for scale. 

To estimate the maximum percent coverage of L. pertusa on a given structure, non-overlapping 

screen shots were taken of each rig at the middle of the 10 m depth interval of maximum colony 

density and at 5 m above and below this depth. Inkscape 0.48.2 was used to outline the structure 

and L. pertusa colonies over the surface of the structure and percent coverage calculated from the 

areas of each (Figure 8-16). This method will overestimate percent coverage as it assumes the 

structural member is flat so structure surface is underestimated and colonies towards the edge of 

the column will obscure a disproportionate area of the actual surface. However, these data were

only used for relative comparisons between platforms and over time.
310

Figure 8-16. Example of screen shot used for percent coverage analysis. Structure G at 304 m 

with 57% of the structure covered with L. pertusa. The structure is outlined in red and 

the L. pertusa covering the platform surface are outlined in black.

8.3.4 Results

The growth rates calculated from the largest colonies ranged from 1.5 to 3.5 cm/yr on the various 

platforms and 0.45 to 1.6 cm/yr on the wrecks. Using the average of the largest 10% of the corals 

measured for this analysis on each structure, the calculated rates ranged from 1.2 to 3.2 cm/yr on 

the platforms and from 0.4 to 1.1 cm/yr on the wrecks. There was a significant linear correlation 

between the age of the structure and the calculated growth rate, with the lower growth rates 

calculated from the older structures (R2 adj. =54.8%, p =0.009, Table 8-2). There was not a 

significant correlation between age and growth rate with individual structure types, all rigs, or only 

wrecks. Using a two-sample T-test, solid/compliant platforms had significantly higher growth 

rates than spar/tension leg platforms (p=0.04) and all rigs combined had a significantly higher 

growth rate than wrecks (p=0.025). 

The shallowest occurrence of L. pertusa on the platforms ranged from 201 m on Pompano to 294 

m on Joliet (Table 8-1). Only one platform examined spanned the entire potential depth range of 

L. pertusa and the deepest occurrence noted on that platform was 801 m (Ram Powell, Table 8-1). 

On all platforms that we were able to survey from above the first occurrence of L. pertusa to the 

sea floor, the density of L. pertusa colonies peaked at some intermediate depth (Figure 8-17). For 

the shallower water platforms, this peak depth was constrained by the platform water depth. On 

the deeper water platforms, the peak in colony density occurred at about 500 m (Table 8-1, Figure 

8-17). 
311

Table 8-2.

Regression statistics for: Growth rate vs. maximum age of corals (Figure 8-23)

1Structure age at the time of imaging. b An average of the earliest and latest possible dates of sinking (96 years) was 

used for the shipwreck Green Lantern.

Figure 8-17. Colony density vs. depth Scatter plot of colony density vs. depth. Petronius=A, 

Pompano=B, Ram Powell=C, Neptune=D, Jolliet=E, Zinc=F. Cognac was not 

included in this analysis because portions of the structure were covered in “thickets” 

of L. pertusa and thus colony density could not be determined. 

1Measurements only 

obtained to 437 m. Structure depth is 524 m.2 Solid or compliant type structures. The 

other platforms are spar or tension leg type structures.

Structure Type(s) Regression Equation

(Minimum growth Rate =)

R2 adj.

(%)

p-value of 

constant

All Rigs and Wrecks – 0.0225 Structure Agea,b+ 2.74 54.8 0.009

All Rigs – 0.0308 Structure Agea + 2.87 0.0 0.42

Compliant/Solid – 0.0344 Structure Agea + 3.39 16.9 0.33

Spar/Tension Leg – 0.0362 Structure Agea + 2.36 89.2 0.15

Wrecks – 0.0285 Structure Agea,b + 3.23 89.4 0.15
312

The maximum densities on the different platforms ranged from about 1 to 10.8 colonies /m2and 

on the older platforms and some wrecks the colonies had merged into thickets (Table 8-1, Figure 

8-17). In general, the highest densities of colonies were observed on the deeper platforms and the 

solid and compliant tower type structures had lower peak and average densities then the spar and 

tension leg type structures (Table 8-1, Figure 8-17).

Another measure of the density of L. pertusa on the artificial structures is the percent coverage. 

Using a one-way ANOVA with post-hoc Tukey’s analysis, there was no significant difference (α= 

0.05) in the percent coverage of areas with maximum colony density on any platforms except the 

oldest platform which had the highest percent coverage (average 65.65%, SD 8.9%). However, 

the lowest maximum coverage occurred on the youngest platform imaged (average 1.67% SD, 

1.13%). All wrecks at appropriate depths had L. pertusa growth at the thicket stage (Figure 8-18) 

and on the two World War II wrecks with extensive relief, coverage was 100% on many portions 

of the ship.

Figure 8-18. Mosaic of L. pertusa thickets growing on the bow of the Gulfoil shipwreck.

Although only colonies where growth away from the attachment substrate could be measured were 

used for the age calculations, the sizes of all colonies were estimated from the photographs. The 

largest colony on a platform with shape consistent with it arising from a single settlement event 

was 5,660 cm2. In general, colony size was least in the depth intervals near the edges of the 

observed depth range and peaked at the same depth as colony density and maximum growth 

(Figure 8-19). On the one platform that spanned the full depth of occurrence of L. pertusa, the 

calculated growth rate of the largest colonies found per 15.25 m (50 ft) depth interval was 

significantly and positively correlated with the density of L. pertusa (R2adj.= 52.2%, p-value < 

0.0001) (Figure 8-20).
313

Figure 8-19. Scatter plots of colony area (size) vs. depth. Petronius=A, Pompano=B, Ram 

Powell=C, Neptune=D, Jolliet=E. Only Ram Powell is in a water depth that exceeds 

the known depth range of L. pertusa. Colony measurements are biased against smaller 

colonies that may not have shown up on poorer quality video and against very large 

colonies at high densities where individual colonies were difficult to distinguish from 

one another. 
314

Figure 8-20. Relationship between highest growth rate and density on different depth segments 

of Ram Powell. The highest growth rate measured in a 12.25 m (50 ft) section of the 

structure plotted against the density of colonies in that section. Ram Powell was used 

for this analysis because it is the only platform in our data set that spans the entire 

depth range of L. pertusa. The regression equation for this data set is. y = 0.088 

+0.79. R2adj.= 52.2%, p-value < 0.0001.

No L. pertusa growth was observed between the sea floor and 5-10 m above the sea floor on any 

structure, although one had L. pertusa growing on the sea floor near the base (Structure G) and a 

colony was found on a mostly buried flowline near another (Structure D). While L. pertusa

colonies are absent on the base of these structures, anemones and other fauna are often present and 

abundant (Figure 8-21).

Of 4,383 L. pertusa colonies measured for this study, fourteen were not white. The non-white L. 

pertusa colonies were observed on four platforms between 276 and 497 m depth. Colors ranged 

from bright orange, various shades of brownish-orange (Figure 8-22a) to one mottled 

brown/orange and white colony (Figure 8-22b). Though non-white colonies on the same rig 

occurred within 50 m of each other, non-white colonies were never observed adjacent to one 

another. 
315

Figure 8-21. Example images of structure bases showing absence of L. pertusa below 5-10 m 

above the sea floor. Approximately 2.5-3 m of structure are visible in each image. a) 

leg of Petronius; b) leg of Pompano; c) riser connection on Neptune; d) abandoned 

flow tube connection at Zinc showing the beginning of L. pertusa colonization 

approximately 8 m off the sea floor.
316

Figure 8-22. Colored L. pertusa colonies - a) An orange L. pertusa colony at ~300 m on Jolliet. 

b) A colony of mixed colored L. pertusa at ~400 m on Jolliet.

8.3.5 Discussion

In this study we examined the growth rates of L. pertusa along with their density and depth 

distribution on artificial structures in the GoM. The highest growth rates reported here (3.47 

cm/yr)are similar to the highest published rates for L. pertusa measured on artificial structures in 

shallower water (Gass and Roberts, 2006). These rates are higher than those reported for deep 

water L. pertusa in the GoM using other techniques such as in situ staining (Brooke and Young, 

2009). Although it has been suggested that corals may have higher growth rates on metal structures 

due to electrical currents generated on those structures (Sabater and Yap, 2002), more recent 

studies found no significant gain in growth rate due to electrical currents, although it has positive 

effects on coral survival (Strömberg, et al., 2010) We consider that this non-invasive method for 

determining growth rate perturbs the coral less and more likely reflects natural rates at the depths 

measured. 

Though growth rates are variable between structures (Table 8-1), overall, growth rates are 

negatively correlated with the age of a structure (Figure 8-23, Table 8-2). This may reflect faster 

growth or younger colonies, and/or the more linear branch growth inherent in early colony growth 

vs. the increased zig-zagging morphology of branches on older colonies. 
317

Figure 8-23. Minimum growth rate vs. age of structure (maximum possible age of coral colony). 

There was no significant relation between growth rate and age of the structure within 

any subgroup and the line shown is for all structures (R2 sdj = 54.8, p = 0.009). See 

Table 8-2for regression statistics.

It is difficult to compare solid/compliant and spar/tension leg structures because no solid/compliant 

structure reached optimal L. pertusa settlement depth. (Table 8-1, Figure 8-17). Possibly because 

of the increased depth available for settlement, the maximum colony densities on spar/tension leg 

structures was approximately four times greater than on solid/compliant structures (Table 8-1). 

Conversely solid/compliant structures have significantly higher growth rates in comparison to 

spar/tension leg structures of similar ages even though all solid/compliant structures are at suboptimal depth for L. pertusa settlement. This may reflect the more massive, cross-braced 

compliant/solid structures affecting currents and facilitating food or oxygen delivery to the corals. 

Despite initial colony densities, percent coverage of L. pertusa on solid/compliant towers and ship 

wrecks is often quite significant (Figure 8-16, Figure 8-18), with large colonies reaching thicket 

stage by 34 years (Figure 8-16, Figure 8-19).
318

There are numerous natural potential source populations, both east and west of the structures 

studied here (Morrison et al., 2011), to provide larva that may settle on deep water installations.

Because we found L. pertusa on every artificial structure examined (including shipwrecks at 

appropriate depths) (Table 8-1, Figure 8-18), there are likely numerous other structures harboring 

substantial L. pertusa growth in the northern GoM.

This study expands the known depth limit for L. pertusa in the GoM from 640 m (Schroeder et al., 

2005) to 801 m (Table 8-1). Ram Powell provided the first opportunity to look at areas suitable for 

L. pertusa settlement throughout a continuous 995 m depth range at a single location. As expected, 

L. pertusa were not present above the thermocline, and it is likely that temperature defines its upper 

depth range in the GoM. Temperatures of 6° C were recorded at the maximum depth of occurrence 

during this study; whether L. pertusa’s depth range is limited by physiological considerations, food 

supply, or lack of propagules cannot be determined from this study. In addition, using Ram Powell

as a model, there appears to be a favorable depth range for L. pertusa settlement at 500-520 m 

(Table 8-1, Figure 8-17) and there is a strong positive correlation (R2adj.= 52.2%, p< 0.0001) 

between the growth rate of L. pertusa and colony density on this structure. For all structures, the 

continuum and variation in L. pertusa colony size throughout the majority of its depth range 

(Figure 8-19) is indicative of regular, reoccurring and ongoing colony settlement as opposed to 

rare settlement events.

In addition to expanding the depth range of L. pertusa, this study is the first to document the 

presence of non-white L. pertusa morphotypes in the GoM (Figure 8-22), though non-white L. 

pertusa are common in the North Atlantic. The rarity and distance separating these non-white 

colonies suggests that they are not clones, but the result of individual larval settlement. The 

absence of non-white L. pertusa on natural substrates in the GoM might indicate that the platforms 

are serving as “stepping stones” for invasion of these colored morphotypes into the Gulf. Though 

it is unknown whether L. pertusa color morphs are linked to genetic differences (Mortensen, 2001), 

it has been suggested that each may harbor different bacteria consortia (Neulinger et al., 2008).

For structures shallower than 800 m, there appears to be some type of “bottom effect” that renders 

the base of structures unsuitable for L. pertusa. (Figure 8-21, Figure 8-17, Table 8-1) even when 

the structure is no longer producing or handling hydrocarbons (i.e., Structure F). Although L. 

pertusa were absent on the bottom 5-10 m of all energy installations examined, other fauna were 

present on this portion of the installations, most notably, fly-trap anemones, suggesting that this 

effect is not the result of anti-fouling agents. The reason for this “bottom effect” is unknown and 

may be due to competition from fauna better equipped to utilize food that falls from upper levels 

on the platforms or some type of unfavorable sediment and/or current condition.

Despite the potential for new and continued L. pertusa habitat on artificial structures in the GoM, 

these are not normal substrates for L. pertusa. On natural substrates, L. pertusa growth can 

progress from single colonies, to thickets, then mature coppices (Wilson, 1979) which provide 

habitat for a variety of species on live, dead, and live/dead mixtures of L. pertusa (Cordes et al., 

2008; Jensen and Frederiksen, 1992; Lessard-Pilon et al., 2010; Mortensen et al., 1995). 

Community biodiversity on and around L. pertusa reefs can be comparable to that of shallowwater reefs (Jensen and Frederiksen, 1992; Rogers, 1999) and can provide habitat for commercial 

deep-sea fish (Ross and Quattrini, 2007). Though artificial structures will provide habitat for 
319

numerous other species, this live/dead mixture of L. pertusa cannot form on vertical or steep 

diagonal structures where dead-bioeroded L. pertusa will be swept away and fall to the sea floor. 

As a result, the communities closely associated with L. pertusa on platforms are not as species rich 

as those associated with natural L. pertusa reefs.

Energy platforms, sub-sea installations, and shipwrecks afford a unique and valuable opportunity 

to study many aspects of L. pertusa biology because of: 1) the known date of installation for growth 

rate and population studies, 2) the large depth range of potential substrate in a single location 

represented by the deeper water platforms, and 3) wide distribution and large numbers of potential 

substrates in known locations of the deep GoM. Here we reported on a relatively small number of 

artificial structures, at very limited points in time. Repeat visits to these and additional structures 

will allow researchers to understand more fully L. pertusa settlement and growth patterns, 

physiological requirements, and the connectivity of populations throughout the GoM. 
320

9 VK906 LOPHELIA MOUND PISTON CORE ANALYSIS

While evaluating 3-D seismic sea floor amplitude data for hard bottom areas that could support 

deepwater coral communities, Dr. Harry Roberts of Louisiana State University’s Coastal Studies 

Institute and BOEM colleague Bill Shedd identified some unusual mounds in the Visoca Knoll 

lease area, block 906. These mounds occur on the upper continental slope south of the late 

Pleistocene “Lagniappe” shelf-edge delta (Roberts et al., 2004) and southeast of the modern 

Mississippi River delta (Figure 9-1). Unlike the acoustically reflective areas (high positive sea 

floor amplitude) that develop primarily because of authigenic carbonate precipitation in 

association with microbial oxidation of hydrocarbons that have migrated to the seabed, the VK906

mounds exhibited low acoustic reflectivity (low positive sea floor amplitudes) and a nonstratified 

or acoustically transparent interior. The morphology and seismic character of the mounds is 

similar to Halimeda bioherms discovered in the eastern Java Sea and opposite the Mahakam Delta 

of Borneo (Roberts et al., 1987) which suggested they may be organically built features and 

therefore made them a focal point of scientific interest.

Azooxanthellate corals of the dark, cold-water environments of the northern GoM continental 

slope are known to have wide geographical and depth ranges. Of these deep-water corals, Lophelia

pertusa is known to build impressive colonies and low-relief mounds (Sulak, 2008). However in 

the Atlantic off the eastern coast of the United States (Newton et al., 1987, Paull et al., 2000, 

Messing et al., 1990; and others), along the north Atlantic-European margins (White et al., 2005; 

Freiwald, 1997, Mortensen et al., 2001; and others), and recently off the coast of Mauritania and 

Angola (Colman et al., 2005, Eisele et al. 2011, Le Gilloux et al. 2009) large lithoherms and 

mounds composed largely of Lophelia coral debris have been recognized and studied. Where agedated, some of these mounds represent developmental time scales of thousands of years. 

However, until large deep-water Lophelia mounds were discovered during the present BOEMNOAA funded project, Lophelia mounds of such magnitude had not been discovered in the GoM. 

In fact, Sulak (2008) indicates that known Lophelia colonies and low-relief mounds in the GoM, 

such as the impressive coverage of Lophelia on the hard substrates of authigenic carbonate in 

VK826 (Schroeder et al., 2005), do not have extensive rubble cones around them or build large 

mounds like the Atlantic examples. The coral-covered mounds found in VK906 are different from 

other Lophelia build-ups so far recognized from the GoM. They are much larger, cone-shaped, 

and from initial surface observations appear to have been constructed of significant accumulations 

of coral rubble.Figure 9-2 A illustrates a 3-D seismic surface amplitude map of the ocean bottom 

area supporting the mounds and an associated North-South oriented seismic profile through several 

mounds. The mounds are located above a shallow subsurface salt body that impacts the 

bathymetry of the area, creating a well-defined low-relief tabular structure with a distinct gullylike depression along the western and southern margins. The sea floor above the salt and in the 

gully-like areas is highly reflective, especially above the edges of the subsurface salt body. By 

contrast, the small mounds have a 3-D seismic surface amplitude that is lower than the general 

background for the area (a very low positive 3-D seismic amplitude).
321

Figure 9-1. The inset in this figure illustrates the location of VK906 on the 

background of computer-shaded multibeam bathymetry of the OCS and 

upper continental slope. The mound identified on this map was cored at 

the crest and flank. Note that the water depth of the mound crest is less 

than 400 m (1,312 ft.) and the base is between 420 m (1,378 ft.) and 430 

m (1,410 ft.). Core locations are shown at the mound crest, mound, 

flank, and an intermound site.
322

The seismic profile of Figure 9-2 B indicates that the mounds have apparently built on a highly 

reflective surface that is clearly displayed outside and lateral to the mounds. This surface is also 

imaged through the largest mound and it appears that the mounds built on this surface. At first, a 

hydrocarbon seep origin was considered for these features. However, as the seismic profile of 

Figure 9-2 B and other profiles not presented in this report illustrate, clear migration pathways 

from the subsurface to the mounds are not easily defined. Later, ROV dives made on the largest 

of the mounds (Figure 9-2 B), as part of the Lophelia II Project, confirmed a lack of hydrocarbon 

seep-related characteristics on the surface of the mound and around it. However, we found that 

the mound crest and upper flanks were densely populated by “thickets” of the deep-water coral 

Lophelia pertusa (Figure 9-3).

These coral “thickets” are defined by the surface roughness on the multibeam bathymetry image 

acquired by the Woods Hole Oceanographic Institution’s Jason II ROV (Figure 9-2 B). These 

observations plus the unique seismic characteristics of this mound generated questions concerning 

whether L. pertusa was actually responsible for constructing the mound or that the present coral 

cover was simply the product of a convenient mounded substrate. In addition, higher total 

alkalinity levels were observed adjacent to the mound at VK906 as compared to the background 

water column. Although broad trends in water column carbonate chemistry could result from the 

complex current structure of the GoM, these highly localized elevations in concentration are not 

likely to be related to large-scale oceanographic patterns. The largest mound and its associated 

subsurface geology does not have characteristics that would lead to an interpretation that it was 

initially built by fluidized sediment extrusion at the seabed. So, how did the mound form, what is 

its developmental history and age? From other studies of deep-water corals and the structures they 

build, mostly concentrated in the northeastern Atlantic, we know that L. pertusa is capable of 

building sizeable mounded features (Freiwald, et al., 1997; Mortensen et al., 2001; White et al., 

2005 and others).

To answer important scientific questions about the VK906 mounds, samples were needed from a 

mound interior. With a modest addition to the Lophelia II Project budget, TDI-Brooks 

International, Inc. was employed to take Jumbo Piston Cores (JPCs) in the largest of the VK906

mounds and in the intermound area where the reflective surface on which the mounds appear to 

have developed could be encountered. On May 28, 2012 cores were acquired using the R/V Brooks 

McCall. The core sites are shown on Figure 9-1. Both Standard Piston Cores (PCs) and Jumbo 

Piston Cores were acquired. The mound crest and flank were cored with the Jumbo Piston Corer. 

A sheared piston bolt prevented a Jumbo Piston Core from being taken at the intermound site. 

Statistics associated with the coring program are given in Table 9-1.
323

Figure 9-2. (A) This combined 3-D seismic sea floor acoustic amplitude and bathymetry map 

generally defines a shallow subsurface and tabular salt body with a gully-like sea floor 

depression along its western and southern flanks. Note that the scattered patterns of 

high surface amplitude generally occur around the flanks of the salt body, but high 

amplitudes are not exclusive to the flanks. The bathymetry defines several mounds 

above the salt body. Seismic line a-a ́ cuts through three of these mounds near the 

southern end of the salt body and is the location of the profile illustrated below. The 

inset is the aft deck of the R/V Brooks McCall on site to collect a Jumbo Piston Core 

from the largest Lophelia mound shown on the seismic profile below. (B) This seismic 

profile is oriented roughly N-S across the shallow tabular salt body over which small 

mounded features occur on the sea floor. The inset is a high resolution bathymetric 

image of the largest Lophelia mound located at the southern edge of the salt body. 

This multibeam bathymetry image was acquired by the ROV Jason II. The 

“roughness” at the mound crest and upper flanks is a reflection of living Lophelia

thickets currently growing on the mound surface.
324

A

B

Figure 9-3. (A) A living Lophelia “thicket” on top of a small mounded structure near the 

crest of the Lophelia mound of Figure 9-2B. (B) Living Lophelia and coral rubble 

on the surface of the largest mound seismically imaged in Figure 9-2B.
325

Table 9-1.

Core acquisition data

Site Type Recovery Data-Time USBL Lat USBL Lon

USBL Depth 

(m)

Intermound PC 14’02” (4.2 m) 5/18/12 7:27 N29 04.3020 W088 22.7054 -428

Mound Flank PC 15’10” (4.8 m) 5/28/12 8:10 N29 04.2028 W088 22.6496 -407

Mound Crest PC 17’08” (5.3 m) 5/28/12 8:49 N29 04.1700 W088 22.6293 -393

Mound Crest 44 JPC JPC 40’05” (12. 3) 5/28/12 10:35 N29 04.1731 W088 22.6287 -379

Mound Crest 2 64ft JPC JPC 53’08” (16.4 m) 5/28/12 13:07 N29 04.1657 W088 22.6316 -377

Mound Flank 64ft JPC JPC 54’09” (16.7 m) 5/28/12 14:58 N29 04.2005 W088 22.6529 -389

**Intermound 64ft JPC JPC 0’ 5/28/12 16:48 N29 04.2994 W088 22.7087 -409

Coordinates are WGS84 UTM 16N M. PC is piston core.**Piston bolt sheared during Jumbo PC deployment at Intermound site;

no recovery

9.1 METHODS OF INVESTIGATION

9.1.1 Mound Discovery

The database used to analyze the continental slope sea floor and shallow subsurface potential coral 

community sites consisted of over 190 time-migrated 3-D seismic volumes acquired over the 

northern GoM continental slope. These data acquired for the oil and gas industry housed at the 

BOEM office in New Orleans and can be accessed for BOEM-sponsored environmental studies 

under proprietary conditions. Sites for data collection using a submersible or ROV were selected 

based on 3-D seismic sea floor amplitude (or acoustic reflectivity) analysis. The details of the site 

selection process are presented in a separate section of this report. The methodology of sea floor 

evaluation for identifying hard bottoms associated with hydrocarbon seeps that may be the sites of 

deep-water coral communities is also presented in Roberts et al. (2010). These methods of 

analyzing BOEM-held 3-D seismic data were used in identifying potential coral community sites 

in support of the Lophelia II Project. The Lophelia mound discussed in this section of the final 

report was discovered by analyzing 3-D seismic data from the continental slope southeast of the 

modern Mississippi River delta, the Visoca Knoll Lease area.

9.1.1.1 Core Acquisition

As previously stated, both Standard Piston Cores with a 7.6 cm (3 in) diameter and larger Jumbo 

Piston Cores (JPC) with a 12.7 cm (5 in) diameter were acquired from the largest and most southern 

mound of the mounds in VK906. The standard piston cores were taken first to test the penetrability 

of the mound prior to risking a bent core barrel with the much longer JPC. Table 9-1 shows that 

two JPCs were acquired from the mound crest, the longest of which was 16 m (53 ft.). The longest 

JPC was acquired from the mound flank. This core was 16.4 m (54 ft.) long. A JPC was not taken 

as planned in the intermound area because of a malfunction of the coring equipment. However, a 

4.2 m (14 ft.) long Standard Piston Core was acquired at the predetermined intermound site.
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9.1.1.2 Core Analyses

Prior to cutting the cores and sampling the sediments for a variety of analyses, the cores were 

analyzed using a remote sensing multisensor core logger, a non-destructive method of testing. 

Multisensor logger profiles are presented for the Mound Crest 2 Core (Figure 9-4), the Mound 

Flank Core (Figure 9-5), and the Intermound Core (Figure 9-6).

9.1.1.2.1 Multisensor Core Logger 

This relatively new system for logging the geophysical properties of sediment cores allows both 

whole cores and split cores to be measured in a nondestructive fashion (Schultheiss and Weaver, 

1992; Schultheiss and McPhail, 1989). The current sensor configuration measures (a) bulk density 

(using gamma-ray attenuation), (b) magnetic susceptibility at user-defined sample intervals down 

the core, (c) electrical resistivity, and (d) compressional (P) wave velocity (500 kHz). Split-core 

logging may provide slightly more reliable results than whole core logging as it mostly eliminates 

core-slumping effects that can lead to spurious results; it also gives higher resolution magnetic 

susceptibility readings. However, in most cases splitting the core may not be practical because of 

other demands such as geotechnical work. Only bulk density, magnetic susceptibility, and 

resistivity were acquired on the mound cores.

Bulk Density: Density is determined by measuring the attenuation of gamma rays through the 

core. A 137Cs gamma source in a lead shield, with optional 2.5 mm or 5 mm collimators, provides 

a thin gamma beam which passes through the core. An integrated gamma detector measures the 

intensity of the beam relative to standards providing the gamma density of the core material. 

Density can be measured with an accuracy better than 1% depending upon count time used and 

cores condition. Calibration standards are machined from a standard aluminum billet and stepped 

to enable calibration equations to be determined. Separate calibration samples are matched to each 

type of core liner used.
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Figure 9-4. Multisensor core logger profiles of Gamma Density, 

Magnetic Susceptibility, and Resistivity for the Mound Crest 

2 JPC.
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Figure 9-5. Multisensor core logger profiles of Gamma Density, 

Magnetic Susceptibility, and Resistivity for the 

Mound Flank JPC.
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Figure 9-6. Multisensor core logger profiles of Gamma Density, Magnetic 

Susceptibility, and Resistivity as well as an example X-ray radiograph for 

the Intermound Standard Piston Core. Note the subtle clay-to-silty clay 

layering revealed in the X-ray radiograph.
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Magnetic Susceptibility: Two sensor systems are available: a loop sensor for use with whole 

cores and a point sensor for use with horizontally split cores. The new point sensor enables downcore spatial resolutions of better than 5 mm to be achieved. Accuracy is typically within 5% 

depending on core quality and type of material. Calibration/check samples are provided with each 

sensor.

Electrical Resistivity: The multisensor core logger is equipped with a non-contact resistivity 

sensor, the newest sensor developed by GeoTek. The non-contact resistivity sensor technique 

operates by inducing a high-frequency magnetic field in the core, from a transmitter coil, which in 

turn induces electrical currents in the core which are inversely proportional to the resistivity. Very 

small magnetic fields regenerated by the electrical current are measured by a receiver coil. To 

measure these very small magnetic fields accurately, a difference technique has been developed 

which compares the readings generated from the measuring coils to the readings from an identical 

set of coils operating in air. This technique provides the requisite accuracy and stability required. 

Resistivities between 0.1 and 10 ohm-meters can be measured at spatial resolutions along the core 

of approximately 2 cm.

Multi-Sensor Core Logger Data Editing: Raw sensor data were processed using calibration 

parameters to provide measurements in standard units of measurement for each sensor. For 

presentation purposes, the words “section break” were included on the multisensor core logger

profiles for those areas influenced by proximity of core endcaps, and obvious gaps in sediment 

visible through core liner. This influence is most significant for magnetic susceptibility, resistivity 

sensors, and p-wave sensors which have lower spatial resolution (> 1 cm) than do sensors for sound 

speed and gamma density (< 1 cm).

9.1.1.3 Digital Core Photography

Each core section was split longitudinally and the surface of one core half prepared for 

photography. The other core half was placed in plastic sleeving to preserve the core for future 

analyses and then placed in a cold storage locker. All sections of each core designated for 

photography were assembled in stratigraphic order and fed into the GeoTek Multisensor Core 

Logger equipped with a high resolution scanning digital camera and data recorded on the system’s 

computer.

9.1.1.4 Age Dating (Radiocarbon and U/Th)

Coral samples were selected for radiocarbon dating from two living Lophelia corals at the surface 

of the mound and at five sites within the Mound Crest 2 core (JPC) ranging from the mound surface 

to a depth down-core of 490 cm (16 ft.). The samples were ultrasonically cleaned before shipping 

to Beta Analytic Inc. of Miami, Florida where they were acid etched and analyzed according to 

standard methodology for producing radiometric dates. After applying a 13C/12C correction, 

conventional age dates were calculated. The Conventional Radiocarbon Age is cited with the units 

“BP” (Before Present). Present is defined as AD 1950 for the purposes of radiocarbon dating.
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A total of five coral samples were selected for U/Th dating over the entire sedimentary 

sequence sampled in the Mound Crest 2 Core (JPC). These samples were ultrasonically cleaned 

prior to shipment to the U/Th dating laboratory at the University of Minnesota. Methods similar 

to those applied to Lophelia corals of the North Atlantic by Schroder-Ritzrau et al. (2005) were 

being applied to the samples collected from VK906.

9.1.1.5 Clay Mineralogy

Selected samples of matrix sediment spanning the entire length of the Mound Crest 2 (JPC) were 

submitted to the X-Ray Diffraction Laboratory in the Department of Geology and Geophysics at 

Lousiana State University for clay mineral analysis. The clay-size (<2μm) fraction from each 

sample was extracted by dispersion in a 0.1% Na3PO4 solution followed by removal of the top 5 

cm of the water column after 3.5 hours of settling. High-speed centrifugation separated the solids 

from the slurry. The extraction was repeated several times. Oriented films were produced by 

combining clay pastes and smearing onto glass slides. X-ray diffraction patterns were collected 

after each sample had been air-dried, exposed to an ethylene-glycol saturated atmosphere, and 

heated to 300°C and 550°C for an hour, respectively. The X-ray diffraction patterns were produced 

with CuKα radiation in a Bruker/Siemens D5000 diffractometer at 40 kV and 30 mA between 2-

36°2θ at an interval of 0.02°2θ per second using a rotating sample holder. A second run will be 

made with the carbonates removed using a buffer pH5 Sodium Acetate-Acetic acid solution in a 

95° oven. Then, the clay-size fraction will be extracted and the resulting smear sample run on 

theX-ray diffractions.

9.1.1.6 Elemental Analyses

Coral samples were selected from the entire stratigraphic interval sampled by Mound Crest Core 

2 (MC-2), a Jumbo Piston Core. The samples were washed in distilled water and ultrasonically 

cleaned to remove matrix sediment from the sample exteriors and within the corallites. The 

samples were dried for 24 hours at 105 °C, then ground to a powder. About 1 g (weighed to four

decimal places) of ground dry coral skeletal materal was placed in a 75 ml glass digestion tube and 

extracted with 5 ml of concentrated trace-metal-grade nitric acid at ~ 120 °C for 8 h. The mixture 

was diluted to 50 ml with deionized water. Metal analyses were performed on the clear supernatant 

using a Varian model MPX ICP-OES.

9.1.1.7 Skeletal Density

Density of L. pertusa skeletons was measured from Mound Crest Core 2 according to the methods 

in Section 3.1.

9.2 INITIAL RESULTS

The data collection on samples from the VK906 Lophelia mound is on-going and only a 

preliminary appraisal of this unusual feature is presently available. Although long cores were 

taken both from the mound crest and mound flank (Figure 9-1) most of the sampling so far has 
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been concentrated on the Mound Crest 2 JPC which was 16.4 m (53 ft. 8 m) long. A JPC was also 

planned for the Intermound site (Figure 9-1), but technical problems during field acquisition 

prevented a long stratigraphic section from being sampled. The point of this Intermound core was 

to sample and date the stratigraphic horizon with high acoustic reflectivity characteristics on which 

the Lophelia mounds above the southern end of the tabular salt body seemed to have developed. 

A Standard Piston Core 4.2 m (14 ft.) long was taken at the site, but preliminary results suggest 

that the highly reflective horizon was not encountered (Figure 9-2).

9.2.1 Lithostratigraphy

Prior to cutting the cores and sampling for a variety of analyses, the cores were logged using a 

multisensor core logger. All cores were logged. The Mound Crest 2 JPC, the Mound Flank JPC, 

and the Intermound Standard Piston Core logging results are presented in this report (Figure 9-4, 

Figure 9-5 and Figure 9-6). Of the two cores acquired from the Lophelia mound, the Mound Crest 

2 core (Figure 9-4) exhibits the most variability in all three logger profiles (Gamma Density, 

Magnetic Susceptibility, and Resistivity). Down-core variability in these properties suggests that 

the mound is not a homogeneous geologic-biologic feature, but that the interior of the mound has 

a definable lithostratigraphy. Although the Mound Flank Core logger profiles exhibit a similar 

variability, the variations are not as pronounced, which probably means a degradation of the 

stratigraphic signal by slumping and other forms of sediment redistribution.

Once special techniques were developed to cut these cores, they were photographed with a highresolution digital camera associated with the multisensor core logger. The entire Mound Crest 2 

core is presented in Figure 9-7 and a close-up of a selected core section is shown in Figure 9-8. 

Several observations can be made about the lithostratigraphy and overall character of the mound 

interior from the combined multisensor core logger data sets and the core photograph. First, coral 

fragments are certainly a major component of mound construction to a depth of 16.4 m (53 ft. 8 

in), the maximum depth of penetration (Mound Crest 2 JPC) at the mound crest. Second, 

concentrations of coral “rubble”, smaller coral fragments, and voids alternate with zones of 

relatively coral-free matrix sediment containing few voids. Although most voids are interpreted 

as being natural structures of the mound interior, some were caused or enhanced by the corecutting process. Third, the matrix sediment is primarily hemipelagic in origin, composed of clay 

minerals and a high proportion of calcareous microfossil tests. A typical X-ray diffraction scan 

(0-36°, 2G) of the mound’s matrix sediment (heated, glycolated, and air dried) indicates the 

presence of dominant clay minerals (smectite, chlorite, illite, and kaolinite) as well as quartz and 

calcite (Figure 9-9). The quartz and calcite (microfossil tests) are found in the clay-size fraction 

but occur mostly in the silt and fine sand fraction. The Mound Crest 2 core photograph, Figure 

9-7, as well as the core logger profiles of Figure 9-4 suggest that the mound has an internal 

stratigraphy. Color variations in the core photography clearly indicate different stratigraphic 

layers. A dark clay layer in Section 4 and a very light gray-to-white unit at the base of the Mound 

Crest 2 core (Section 11) are two dramatic examples. Preliminary results from X-ray diffraction 

data (Figure 9-10) indicate down-core variations in clay mineral composition suggesting different 

sediment sources for the clay fraction of the hemipelagic matrix sediment. Data collection is ongoing on the Mound Crest 2 core. 
333

Figure 9-7. This high resolution digital image of the Mound Crest 2 JPC illustrates that 

corals occur throughout the mound which was sampled to a depth below the 

mound surface of ~ 16 m (53 ft.). The JPC was cut into eleven sections, as shown 

in this photograph.

Samples of the matrix sediment spanning the entire sedimentary sequence sampled by this core 

are currently being analyzed for variations in clay minerals and a similar suite of coral samples are 

being analyzed for trace metals. These data sets will be combined with age dating, results of 
334

biostratigraphy, and coral density measurements to derive a developmental history for the mound. 

The Mound Flank and Intermound cores are currently being sampled for similar analyses as 

described above in order to compile a more complete depositional history for the VK906 mound.

Figure 9-8. This photograph is a close-up of the 

middle of Section 4 of the Mound Crest 2 

JPC illustrated in the previous figure. 

Note the densely packed coral “sticks” 

and smaller fragments. The matrix 

sediment is rich in clay minerals and 

calcareous microfossil tests. The width 

of the core photograph is ~ 12 cm (5 in).

9.2.2 Biostratigraphy and Age Dating

Biostratigraphy of the VK906 mound is being developed by long-time colleague on continental 

slope studies, Dr. Barry Kohl, formerly with Chevron and now an adjunct professor at Tulane 
335

University. In addition to biostratigraphy, age dating by carbon-14 (C-14) and uranium/thorium

(U/Th) was accomplished on selected samples sent to Beta Analytic Labs and the University of 

Minnesota’s U/Th dating lab, respectively. Two of the fundamental questions about the VK906

mound concerns its age. When did the mound start growing? What was its developmental history? 

Because of the intensive paleontological and sedimentological work conducted in support of the 

oil and gas industry, the northern GoM has a well-developed biostratigraphic framework. Figure 

9-11 is a stratigraphic chart for the GoM illustrating oxygen isotope stages and biostratigraphic 

zones. Initial results of the biostratigraphic analysis are summarized in the depositional rate curve 

for the Mound Crest 2 core (Figure 9-12). One of the initial surprises came from the dating of 

microfossils from matrix sediments at the top of the core as well as C-14 dating of a coral fragment 

near the core top. Both data-points indicate that beneath the “thickets” of Lophelia corals living 

on the surface of the mound, the sediments and coral fragments suggest the mound surface may be 

as old as 40 ka BP (thousand years Before Present). Table 9-2 presents C-14 dates from two 

samples of living coral from Lophelia communities at the crest of the mound and coral samples 

collected from the Mound Crest 2 core. It is not unexpected that a sample from a living coral 

colony could be as old as 700 BP. Surprisingly, dates from samples beneath the top sample from 

the mound sediments are beyond the range of C-14 dating. Biostratigraphically, the top sample 

from the Mound Crest 2 core was in the Pleistocene with the absence of Gl. menardi(i), abundant 

Globorotalia crassaformis and common Gl. inflata (interpreted as Zone Y, Figure 9-11). This 

assemblage of planktonic foraminifera suggests that the mound surface is older than 12 ka BP. 

The microfossil data coupled with the C-14 age of over 40 ka BP, for surface coral debris, indicates 

a long period of nondeposition or erosion (Figure 9-12). Previous slope studies indicate that in 

some areas of the Viosca Knoll lease area, Holocene hemipelagic sediments are over 3 m (9.8 ft.) 

thick. These sediments are completely absent from the Lophelia Mound Crest 2 core.

Table 9-2.

Radiocarbon Dating

SAMPLE NUMBER ESTIMATED AGE

CONVENTIONAL RADIOCARBON

MC 2 (Living) 360 +/- 30 BP

MC 2 (Living) 710 +/- 30 BP

MC 2 – (Surface) 40,710 +/- 670 BP

MC 2 – 75 cm Dead Date

MC 2 – 230 cm Dead Date

MC 2 – 405 cm Dead Date

MC 2 – 490 Dead Date

U/Th DATING

MC 2 – 18 cm 1,391 ± 6

MC 2 – 371 cm 74,924 ± 225

MC 2 – 410 cm 69,496 ± 185

MC 2 – 1125 cm 202,618 ± 1216

MC 2 – 1620 cm 281, 184 ± 2796

MC= mound crest ; BP = before present
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Section 3 of the Mound Crest 2, core photograph (Figure 9-7) contains Gl. flexuosa (Zone X, 

Figure 9-11) indicating a warm period during the Pleistocene, ≥ 89 ka BP. Thirteen samples 

collected between 4.1 m (13.5 ft.) and 15.6 m (51.3 ft) below the sea floor all had consistent 

occurrences of Gl. flexuosa. However, as Figure 9-12 indicates, there is another prominent 

unconformity at approximately 4 m below the sea floor in the Mound Crest 2 core. It is estimated 

from the biostratigraphy that sedimentary section between 65-89 ka BP is missing from the mound 

at this horizon.

At the bottom of the core (~ 16 m or 52 ft. below the sea floor) a distinctive “light grey-to-white” 

unit occurs (see the Mound Crest 2 core photography, Figure 9-7). This unit contains abundant 

Gl. inflata and no Gl. flexuosa indicating a cool water period, below the 5e highstand, which is 

interpreted to be in Zone W, (Figure 9-11) ≥ 130 ka BP. However, U/Th dates from this horizon 

suggest that it is much older.

Table 9-2 presents both radiocarbon and U/Th age dates for the Mound Crest 2 core. The top U/Th 

date puts the mound surface in the Holocene while the radiocarbon data places the surface at ~ 40 

ka BP (Pleistocene). The U/Th date at 18 cm (7 in) below the mound surface may have resulted 

from a fragment of very young coral being buried by bioturbation and subsequently captured in 

the JPC. In the test Standard Piston Core taken from the Mound Crest, abundant Gl. menardii,

indicating younger Holocene were found along with rare occurrences of Gl. inflata and common 

Gl. crassaformis indicating a microfossil assemblage of mixed Holocene and Pleistocene age(s). 

The U/Th date of 74.9 ka BP, at 371 cm (146 in), is just above the unconformity identified 

biostratigraphically (Figure 9-12) and in the same basic age range interpreted from planktonic 

foraminifera.

The sample dated by U/Th just below the unconformity, 410 cm (161.4 in), is slightly younger (69 

ka BP, Table 2) than the sample above it. This sample appears to be in the Gl. flexuosa zone which 

has a minimum date of 89 ka BP. The planktonic foraminifera suggest that there may be a 

transition zone between the 371 cm (146 in) and 410 cm (161.4 in) horizons. Mixing of sediments 

and resulting dates from this zone are highly probable.

The remaining two U/Th dates are not easily resolved with biostratigraphy data. Five new U/Th 

dates are now being processed and more samples are being taken to refine the biostratigraphic 

analyses of the Mound Crest 2 core as well as the Mound Flank and Intermound cores.
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Figure 9-9. X-ray diffraction data (0-36° 2ө) of the matrix sediment (depth of 15 m below the 

sea floor in the Mound Crest 2 core) illustrating the presence of smectite, chlorite, 

illite, and kaolinite on heated, glycolated, and air-dried scans. Quartz and calcite

(microfossil tests) are also present, but mostly in the silt and fine sand fraction.
338

Figure 9-10. (A) Clay minerals in the Mound Crest 2 core matrix 

sediment at the 0.5 m (1.6 ft.) level. (B) Clay minerals in the 

Mound Crest 2 core matrix sediment at the 10.5 m (34.4 ft.) 

level.
339

Figure 9-11. A stratigraphic chart for the GoM showing the oxygen isotope 

stages, biostratigraphic zones and subzones, and tephra (after Kohl et 

al., 2004). All dates are in conventional years BP.
340

Figure 9-12. A depositional rate curve for the Mound Crest 2 core (MC-2), Viosca Knoll Block 906. 

The graph illustrates two unconformities encountered in the core. The first is at the sea 

floor with an age of 40 ka BP, based on a 14C date from a Lophelia pertusa coral sampled 

from top of core. The second unconformity is based on foraminiferal biostratigraphic 

datums and represents 24 ka of missing section. The left hand column shows the 

boundaries of the foraminiferal Ericson zones interpreted by Kennett et al. (1972). A 

projection based on the sedimentation rate shows that approximately six m of core may be 

missing from the top. The X/W boundary was reached at 16 meters below sea floor. All 

dates are in conventional years BP.
341

9.2.3 Skeletal Density

Skeletal density of Lophelia (Figure 9-13) throughout the mound may provide information 

concerning aragonite saturation state at this site over the time course of mound formation. Initial 

investigation of skeletal density does not show a clear trend over time, but does show a series of 

discontinuities that may correspond to the trends observed in the stratigraphy. The skeletal 

densities of living corals from the site show the same range as the entire core section. This suggests 

that, if there is an effect of alkalinity on skeletal density, that the present day range of alkalinity 

experienced at the site is similar to the range of conditions that have occurred throughout the 

history of coral growth at VK906. In the top section of the core, down to approximately 4 m, the 

density of the coral skeleton is relatively high, from 2.7 to 2.9 g cm-3. Below this section, from 4.5 

to 7 m, average density is lower, and the lowest values recorded were present. From 7 to 9 m, 

skeletal density was relatively high. Below this point in the core, most of the data fall into the 2.7 

to 2.9 g cm-3range, with some low values also recorded. 

Low densities could either represent a change in the aragonite saturation state under which the 

corals are laying down their skeleton, or a change in growth rate. High skeletal density would 

result from high omega values, or relatively low growth rates. A boron proxy for calculating pH 

from Lophelia skeletal samples is currently under development as part of a collaboration between 

the Cordes lab and the Prouty lab at USGS. Once this proxy has been calibrated, it will be used to 

determine the oceanographic conditions under which the coral skeleton formed, and will elucidate 

the factors that have resulted in the densities measured. 
342

Figure 9-13. Skeletal density of Lophelia pertusa samples from the 

Mound Crest 2 core.

343

10 ARCHAEOLOGY

10.1INTRODUCTION

10.1.1 Overview

The historic shipwreck component of the Lophelia II Study was planned around a four-year 

timeline and detailsinvestigations of six historic shipwrecks. Years one through three of the project 

was dedicated to fieldwork, historical research, data collection, and data analysis. The fourth year 

of the project involved additional research, data analysis, and reporting. 

The shipwreck component is an important continuation of the MMS’s 2004 Deep Wrecks I Study

(OCS Study MMS 2007-015). It will expand our knowledge base of how shipwrecks function as 

artificial reefs and allow scientists to compare findings and test hypotheses put forth in the first 

study findings. The inclusion of wooden hull shipwrecks in this study provides new information 

on deepwater reef processes since these wrecks represent long-standing areas of composite and

hard substrate in a mostly barren seafloor environment. These studies and others like them will

continue to help researchers understand the processes and importance of deep-water shipwrecks 

as significant archaeological site, but also as artificial reef environments. 

Archaeologically, the documentation, identification, and analysis of additional deepwater 

shipwreck sites increases our understanding of deepwater wreck site formation processes, wreck 

deterioration rates, and the role of the GoM shipping in both regional and global maritime history. 

The study of these deepwater wrecks will allow theBOEM, formerly the MMS, to refine their

avoidance criteria predictive model developed during the Deep Wrecks I Project. This predictive 

model is another tool that government agencies, such as the BOEM and other archaeological 

researchers can use to accurately assess the potential limits of a wreck sites, establish adequate 

avoidance areas around them, and develop comprehensive research designs. 

10.1.2 Archaeological Component Objectives

1. To record each vessel through detailed imagery to establish its type, date of 

construction and positive identification if possible.

2. To establish nationality, ownership (past and present), use history, cause of loss, 

mission and cargo at time of loss through fieldwork and historical research.

3. To determine the extent and condition of the artifact assemblage on each vessel and 

the presence of diagnostic artifacts.

4. To determine potential eligibility to the National Register of Historic Places 

through archival research and the analysis of imagery and to prepare a National 

Register nomination form for potentially eligible vessels.

5. To assess impacts of biofouling communities to these shipwrecks to determine the 

stability of these sites and rate of deterioration.

This multidisciplinary study focuses on the biological and archaeological aspects of seven GoM

shipwrecks in the north-central portion of the GoM. Four of these wrecks represent wooden sailing 

vessels of unknown age and origin, while the remaining three (Gulfpenn, Gulfoil, and U-166) were 
344

lost to wartime activity between early April and late July 1942. All seven shipwrecks were 

discovered during oil and gas surveys and were reported to the MMS as required by Federal 

regulations. Water depth at the investigation sites ranges from 534 to 2,270 m. Each shipwreck 

was investigated to determine site boundaries, National Register eligibility, preservation state and 

stability, and the potential for man-made structures or objects to function as artificial reefs in 

deepwater (Figure 10-1).

10.1.3 Project Organization

The BOEM and NOAA’’s Office of Ocean Exploration (NOAA OE) organized the study under 

the auspices of the National Oceanographic Partnership Program (NOPP). TDI Brooks, Inc., the 

primary contractor for this study, contracted C & C Technologies, Inc. (C&C), to oversee the 

archaeological analysis. C&C contracted the PAST Foundation (PAST) to assist in the 

archaeological component of the study. TDI Brooks, Inc. contracted Droycon Bioconcepts, Inc. 

(DBI) to undertake the micro-biological assessments related to the archaeological component. 

The Key Personnel for the project are listed in the following table (Table 10-1).

Table 10-1

Key Archaeological Component Personnel

Personnel Title Organization

Daniel Warren, MA Marine Archaeology Principle Investigator C&C

Robert Church, MA Marine Archaeology Co-Principle Investigator C&C

Robert Westrick, MA Marine Archaeologist C&C

Shawn Arnold Marine Archaeologist C&C

Sheli Smith Marine Archaeologist PAST

Anne Corscadden Knox Marine Archaeologist PAST

Roy Cullimore Microbiologist DBI

Lori Johnston Microbiologist DBI

10.2GEOGRAPHIC OVERVIEW

The GoM is a semi-enclosed small ocean basin that formed by Late Triassic to Early Jurassic 

rifting followed by Late Jurassic to Early Cretaceous seafloor spreading. The Gulf has been 

receiving sediment influx dominated by the Mississippi River since Late Jurassic. Sediments 

accumulated along the GoM’s northern margin during the Mesozoic and the Cenozoic have 

attained a thickness in excess of 14.9 km. Rapid deposition along the northern margin of the GoM

during the Tertiary and the Quaternary resulted in the accumulation of particularly thick 
345

sedimentary sequences and an up to 296 km basinward migration of shelf edge since the 

Cretaceous at an exceptionally high rate of 4.8 to 5.9 mm/year (Coleman et al. 1991).

Figure 10-1. Overview map with locations of shipwrecks examined in this study.

The Mississippi Canyon is the conduit for source materials moving seaward into the Mississippi 

Fan. Bouma et al (1985) describes the Mississippi Canyon as a major erosional and partially filled 

structure. Initial development of this canyon is suggested to have begun about 50,000 to 55,000 

years ago in the middle continental slope and retrogressed onto the shelf 25,000 to 27,000 years 

before present. Retrogressive large-scale slumping on an unstable shelf-slope areas during a sea 

level low stand or during the initial sea level rise are believed to have caused the canyon to widen 

and lengthen further up-shelf. Several other smaller-scale canyons create fans by similar processes 

east and west of the Mississippi Canyon on the shelf-slope area (Bouma et al. 1985).

In the east-central GoM, a large regional, deep-water feature exists that is identified as the 

Mississippi Fan. This feature was the subject of the Deep Sea Drilling Project Leg 96 in 1983 and 

was interpreted as a channel-levee-overbank complex. The Mississippi Fan is approximately 560 

km long and up to 600 km wide. It extends southeast from the base of the continental slope at a 

depth of approximately 300 m, across the continental rise and onto the abyssal plain, to a point 

roughly halfway between the Campeche Escarpment and the Florida Escarpment. The Mississippi 

Fan is bounded by the Texas-Louisiana Slope region to the west and the Florida Escarpment to the 

east. Water depths for the Mississippi Fan range from approximately 300 m at the base of the 

slope to 3,200 m on the abyssal plain. The fan has been described as a broad arcuate submarine 

fan comprised of a number of fan lobes separated by pelagic oozes or muddy sediment (Bouma et 

al. 1985).
346

In 1989, following an examination of the most recently deposited fan lobe, Bouma and others 

suggested a sea-level-driven model which effectively divided the Mississippi Fan into three 

sections for descriptive purposes: upper fan, middle fan, and lower fan. The upper Fan has a 

slightly convex shaped surface with a wide channel at its apex flanked by laterally discontinuous 

reflectors believed to be overbank deposits. The middle fan holds the greatest accumulation of 

sediment and is imaged on sonar data as a leveed, sinuous channel complex that averages 1.2 to 

2.5 km in width. Less prominent channel complexes that undergo rapid channel abandonment 

define the lower fan. It can be assumed similar fans have been active during the geologic past in 

the entire Mississippi Canyon, Atwater Valley, and Lund Areas. Channel deposits consist of fining 

upward turbidite sequences (gravel to clay size) with the base of the gravel representing the time 

of the episodic event (Bouma et al. 1989). 

10.3HISTORICAL BACKGROUND

10.3.1 Maritime Activity in the Northern Gulf of Mexico 1800-1820

At the beginning of the nineteenth century, the GoM was an arena of commerce, political unrest, 

and piracy, each one intertwined with the other. In 1800, newly elected President Thomas 

Jefferson appointed Robert Livingston as the United States’ minister to Spain. Jefferson 

immediately sent him to purchase the city of New Orleans and the surrounding area from the 

Spanish Crown. After his arrival in Spain, Livingston discovered Spain had secretly traded the 

Louisiana territory to Napoleon Bonaparte of France. Thomas Jefferson feared French control of 

the Mississippi River would cause serious trouble for American shipping in the GoM. Jefferson, 

therefore, dispatched Livingston and James Monroe to Paris in 1803 to negotiate the sale of New 

Orleans to the United States. Napoleon was initially unreceptive to the offer. He was, however, 

at war with Britain and became apprehensive that Britain, already with a naval presence in the 

GoM, would take Louisiana from him before he could secure the region. Eventually, Napoleon’s 

concern over the ongoing war with Britain and the need of money to finance the war led him to 

make a surprising offer. Instead of just New Orleans, Napoleon offered up the entire Louisiana 

Territory to Livingston and Monroe. Although authorized only to buy New Orleans, Livingston 

and Monroe returned home having negotiated the purchase of the entire Louisiana Territory, nearly 

doubling the size of the United States (Tindall 1988; and Bradshaw 2002). 

During negotiations for the purchase of the Louisiana Territories, the territorial boundaries were 

only vaguely defined. When Livingston asked the French foreign minister about the boundaries, 

the minister replied that Livingston had “made a noble bargain” and America would no doubt 

“make the most of it.” The vague boundaries gave the United States a strong claim to parts of 

Texas and Florida in addition to Louisiana. The Spanish were furious when the sale was made 

public, claiming that Napoleon had no right to agree to sell the territory before he actually took 

possession of it. By 1806, clashes between Spain and America over disputed territory led to a 

lawless no-mans-land for several miles east of the Sabine River that became a haven for thieves, 

smugglers, and pirates (Figure 10-2) (Tindall 1988; and Bradshaw 2002).
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Figure 10-2. North-central Gulf Coast in 1806.

The first two decades of the nineteenth century were a heyday for privateering, piracy, and other 

illicit activities in the Caribbean and the GoM as the war between France and Britain wore on and 

Spanish influence in the new world waned. During this period, warring countries bolstered their 

sea power by issuing Letters of Marque to private men-of-war to attack enemy ships for profit. 

The value of these captured ships, referred to as prizes, was to be split between the privateer and 

the government. In the words of author William C. Davis, “The English preyed on the French, the 

French upon the English, and everyone went after the Spaniards’ vessels.” The line between 

privateering and piracy was often blurred as many privateers also engaged in smuggling and were, 

at times, indiscriminate in their attacks on merchant shipping. In 1803, the United States outlawed 

the importation of foreign slaves, making slave smuggling a profitable enterprise and Spanish slave 

ships attractive targets for privateers and pirates. The high demand for cotton production spurred 

on the slave trade and the availability of new land allowed cotton and sugarcane plantations to 

boom in the Louisiana Territory. The market for slave labor continued to rise and New Orleans 

was the doorway for this commerce, legal and illegal alike (Davis 2005; and Bradshaw 2002). 

On April 30, 1812, barely a month after Louisiana became a state; the United States declared war 

on England in response to the British practice of illegally impressing American sailors into the 

Royal Navy. The Gulf Coast was ill prepared for the war and the impending British invasion. In 

December 1814, British forces invaded the Lower Mississippi Valley, entering Lake Borgne to the 

east of New Orleans. The British arrived with a fleet of fifty naval vessels including several 74-

gun ships of the line. These included Tonnant, Ramillies, and RoyalOak along with various 

frigates, brigs, and armed transports. The Americans met the opposing force with a small defensive 

navy composed of the 22-gun sloop Louisiana, the 14-gun schooner Carolina, several lightly 

armed gunboats, and a few other small vessels. The Americans lost the majority of their gunboat 

flotilla near Lake Borgne and the British destroyed Carolina in the Mississippi River south of New 

Orleans (Eller et al. 1965; Dudley 1992). Despite heavy naval losses, Jackson’s forces, comprised 

of mostly militia, repelled the British Army’s advance on New Orleans (Davis 2005). 
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Before 1812, most waterborne commerce in the central part of the Gulf was centered on New 

Orleans. On January 10, 1812, the first steamboat arrived at New Orleans from Pittsburgh. Soon 

after the introduction of steam vessels, maritime commerce in the GoM increased dramatically 

(Pearson et al., 1989). This increase in commerce resulted in cities growing rapidly which led to 

outbreaks of diseases such as cholera and yellow fever. The first outbreak of cholera in New 

Orleans is documented as having arrived by steamboat in late October 1832, shortly after an 

outbreak of yellow fever. The outbreak lasted just over three weeks and left nearly 5,000 people 

dead. In 1848, cholera was again brought to New Orleans by merchant vessel and killed 1,641 

people in two weeks. Despite the disease being linked to bowel discharge around 1866, cholera 

returned almost every year until 1875. The threat of disease was so great that cities began forcing 

vessels to quarantine (Figure 10-3) before any unloading operations (Duffy 1971). 

Figure 10-3. Illustration depicting New York Harbor quarantine of immigrant 

vessels (Graetz, 1883).

During the Civil War, the GoM was a theater of conflict for Union blockaders, daring blockaderunners, and Confederate “commerce raiders” or privateers. Early in the war, U.S. President 

Abraham Lincoln proclaimed a blockade of Southern ports. Confederate President Jefferson Davis 

responded to this action by issuing letters of marque to Confederate privateers allowing them to 

attack U.S. shipping. By January 1862, the converted mail steamer CSS Sumter had captured or 

destroyed eighteen U.S. merchant ships on her cruise from New Orleans to Gibraltar. The CSS 

Alabama sank the steamer USS Hatteras off the coast of Galveston, Texas in the summer of 1862. 

CSS Alabama sank a record seventy-six vessels before being sunk herself off the coast of 

Cherbourg, France by the USS Kearsarge (Watts, 1988).
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After the Civil War, the presence of stern-wheelers began to increase in frequency. A variety of 

sailing craft such as schooners, clippers, and “New Orleans” luggers were, however, still in 

demand along the northern Gulf coast. These vessels carried merchant goods such as lumber, 

naval stores, and cotton to major ports such as Pensacola, Mobile, and New Orleans, as well as 

ports along inland waterways and foreign destinations. Although most histories focus on steam 

vessels in the last half of the 19th century, the amount of traditional sailing vessels outnumbered 

steam ships nearly 2 to 1. Between 1868 and 1897 the total number of sailing vessels built and 

documented in the U.S. equaled 18,344 with a combined tonnage of 2,916,470.88 compared to 

10,231 steam vessels with a combined tonnage of 2,903,226.62 (Commissioner of Navigation 

1897). The overall tonnage of steam vessels increased as a greater number of large screw-driven 

vessels started being produced in 1879. Screw-driven vessels provided the means to increase transoceanic commerce. 

The need for steam propulsion decreased with the beginning of oil production in Louisiana and 

Texas at the onset of the twentieth century. By around 1915, steam engines began to fade away 

as diesel engines emerged (Pearson et al. 1989). Although oil production in this region led to 

increasingly larger vessels being constructed with experimental designs to transport this new 

commodity with greater profitability, the need for wooden sailing vessels never ceased (Flodin 

1919). Wooden vessels continued to be used for fishing, transportation and commercial shipping. 

The naval stores and timber industries were rapidly spreading across the southern states and 

smaller wooden vessels were used to move the products from inland waterways to the Gulf Coast’s 

major ports. Wares would then be transferred to larger sailing vessels and shipped around the 

globe (Bloomster 1940). 

10.3.1.1 Wooden Vessel Types

Between 1770 and 1830, the common types of sailing vessels in the GoM included ships, barques, 

sloops, schooners, brigs, brigantines, luggers, and clippers and others, as described below.

. The largest class of sailing vessel, called a ship contained at least three masts, square-rigged on 

each mast, and included a bowsprit. 

Barques were similarly rigged to ships, but had only fore-and-aft sails on the mizzenmast. Ships 

and barques were generally employed as merchantmen for transoceanic voyages (U.S. Dept. of the 

Treasury, Bureau of Statistics 1886; and Swanson 1991). Sloops were quite common globally and 

one of the oldest styles of vessels utilized for trade in the Americas. They were small vessels, 

often less than 50 ft in length. They carried a single mast with a bowsprit and rigged with foreand-aft mainsail, and jib or foresail. Sloops could sail close to the wind and were highly 

maneuverable in narrow waters. Their seaworthiness and sailing characteristics made them 

popular vessels to both merchants and privateers (U.S. Dept. of the Treasury, Bureau of Statistics

1886; and Swanson 1991).

Fore-and-aft rigs include schooners, brigs and brigantines. This type of rig was prominent in the 

Caribbean and, over the course of the eighteenth century, adopted into shipbuilding in North 

America. The brig, brigantine, and schooner are examples of the impact of the Caribbean 

Bermuda-rig (Smith 2007). 
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Small coastal schooners were introduced in American waters during the early eighteenth century. 

Schooners are typically two-masted, fore-and-aft rigged vessels, often with light square topsails. 

They are fast and relatively easy to handle. The early coastal schooners were typically 20 to 90 

tons and 50 to 90 ft in length. By the late nineteenth century, larger schooners of over 300 tons 

and greater than 100 ft in length became common. These larger vessels often carried more than 

two masts (Swanson 1991; and U.S. Dept. of the Treasury, Bureau of Statistics 1886). 

Brigs and brigantines were popular vessels for coastal trade by the last quarter of the eighteenthcentury. The terms brigs and brigantines are often used synonymously in historical documents, 

but the rig and period of introduction are slightly different. Brigs, common in the Americas by the 

mid-eighteenth century, are two-masted, square-rigged vessels with a fore-and-aft sail (or gaff) on 

the main mast, which aided maneuverability (Figure 10-4). Brigantines are a later adaptation of 

the brig. They have a brig foremast, but with a main mast similar to a schooner except they carry 

a light topsail on the main mast. It is impossible to tell the difference between the two vessels 

archaeologically unless the masts and sparring are present. Brigs/brigantines could take advantage 

of light winds and easily navigate coastal waters. Their intermediate size, approximately 100 to 

130 ft in length, and rig versatility made them well suited for the coasting trade (Smith 2005; U.S. 

Dept. of the Treasury, Bureau of Statistics 1886). 

The lugger derives its name from the dipping lugsail. The lugsail is a modification of the square 

sail which allows one corner of the sail to rise above the mast. Luggers may have one to three 

masts and were used for coastal fishing (U.S. Dept. of the Treasury, Bureau of Statistics 1886). 

Clipper ships were modeled after French luggers that visited American ports during the 

revolutionary war. Clippers were designed by lengthening the lines of swift sailing coastal vessels 

to incorporate a ships rigging. They are characterized by a curving stem that lengthens the bow 

above the water, concave waterlines that draw out and sharpen the forward body of the ship 

creating the widest breadth of the vessel further aft than traditional ships, and a rounding up of the 

transom causing the stern to be lighter (Figure 10-5). The name clipper is thought to be derived 

from the term clip, which was used at the time to describe something that runs or flys smoothly. 

The fast sailing clipper ships were said to clip over the waves and not through them. Until the 

advent of screw-driven diesel vessels, clippers were the fastest vessels on the water (Clark 1910).
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Figure 10-4. Typical nineteenth-century brig (U.S. Dept. of the Treasury, Bureau of Statistics

1886).

Figure 10-5. Clipper ship Young American (Clark 1910).
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10.3.1.2 Sheathing

Adding to the hazards of tropical weather and political instability, the warm waters of the 

Caribbean and GoM were home to a distinctive biological combatant: the shipworm (Teredinidae). 

Proportionally more vessels were lost to shipworm damage than to war and weather. Christopher 

Columbus and other explorers left vessels in the Caribbean because by the time they were ready 

to return to Europe, the ships were unseaworthy due to shipworm damage to the hulls (Smith 

2007). The most common shipworm type is Teredonavalis. Teredos are actually highly 

specialized wood-eating marine bivalves (mollusks). They can be found throughout the world, but 

are more densely concentrated in the Caribbean Sea than most other bodies of seawater. Adult 

Teredos can survive freezing temperatures and varying salinity after boring inside of a wooden 

hull, which allowed Caribbean species to spread through the world’s oceans during the age of 

exploration. Shipworms earned the name “termites of the sea” because they could destroy the 

interior part of a wooden structure before the damage was noticed externally (Turner 1966). 

Shipwrights used various methods over the centuries to protect ship hulls from these marine borers, 

including lead sheathing and sacrificial planking. Global expansion following the fifteenth and 

sixteenth centuries made voyages to tropical waters commonplace and increased the need for better 

hull sheathing technology (Jones 2004).

The search for a better sheathing material led to the suggestion of copper as early as 1708, but it 

was considered too expensive to develop (Jones 2004). By the 1750s, the British Royal Navy 

reconsidered the use of copper sheathing. Despite galvanic corrosion problems during experiments 

with copper sheathing on warships during the 1750s to 1770s, the Navy adopted copper sheathing 

in the 1780s (Lavery 2000; Jones 2004). The advantages of copper sheathing on naval vessels led 

to increased usage on merchant vessels. Merchants sailing in tropical waters found the sheathing 

increased the ship’s life and the widespread use of copper sheathing led to standardization of 

copper sheathing nail patterns during the latter part of the eighteenth and early nineteenth centuries 

(McCarthy 2005; Smith 2007). The rise in the number of coppered hulls is reflected in British 

ship registries. During the 1780s, only 3 percent of registered British shipping was sheathed, but 

by 1816, this number increased to 18 percent (McCarthy 2005). The sheathing of merchant ships 

appears to have been trade dependent. Slavers, East Indiamen, and post office packets were the 

most commonly coppered vessels. However, any ship in a high-return trade that voyaged to the 

southern hemisphere or to tropical waters was likely to be coppered (McCarthy 2005). 

Manufacturing techniques for rolling copper sheathing changed very little until the 1830s. In 1832, 

George Frederick Muntz formulated an alloy of 40 percent zinc and 60 percent copper that he 

called Muntz metal. Throughout the mid- to later nineteenth century, Muntz metal became the 

sheathing standard and led to the introduction of standard sheathing sizes (approximately 18 in by 

24 in) and gauges (18, 20, and 22) (Lavery 2000).

10.3.2 World War II in the Gulf of Mexico

Three factors have influenced the GoM’s role in trade, economic development, and maritime 

commerce: exploration, warfare, and natural resources. Deep canyons mark the Gulf region’s 

submerged bottomlands. Natural resources around the GoM including cotton, tobacco, and 

petroleum products have driven the Gulf’s economy and shipping since the sixteenth century. 

Shipping routes follow traditional patterns, and shipwrecks are often found near those trade routes. 
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The GoM is no exception, and shipwrecks from the age of exploration through modern day have 

been located near traditional shipping lanes (Garrison et al. 1989).

World War I saw an increase in GoM tanker traffic as petroleum products became more important 

to American industry. Although Atlantic coast shipping was threatened during WWI, the Gulf’s 

maritime community was affected little during the First World War. The situation was different in 

World War II. During World War II, several German U-boats operated in the GoM, using shipping 

lanes and navigational beacons to locate and torpedo unsuspecting prey (Blair 2000:467, 498).

In 1942, the world was at war and Germany controlled most of Europe. Hitler launched Operation 

Drumbeat under Admiral Karl Dönitz’s command. Using Germany’s Unterseebootes (U-boats), 

Operation Drumbeat brought the war to United States coastlines. The U-boat mission was simple: 

disrupt Allied supply lines. World War II U-boats struck shipping along the Atlantic coast, and 

infiltrated the United States’ undefended backyard - the GoM. U-boat’s specifically targeted 

tankers carrying valuable petroleum products from the Gulf coast to American refineries and 

abroad. During the early war years, Americans had a false sense of security created by the vast 

oceans that kept the war at a distance. When U-boats entered the GoM, many German commanders 

noted that coastal lights burned as in peacetime.

The spring of 1942 was an opportune time for U-boats in the GoM. The Commander of the Gulf 

Sea Frontier had not yet ordered mandatory convoys and naval escorts. Likewise, many 

merchantmen sailing Gulf waters were unarmed and unaware of the U-boat threat. Until July 

1942, the Gulf remained a German pond where the U-boats hunted and attacked at will (Blair 

2000: 588). 

U-507, under Korvettenkapitän Harro Schacht’s command, torpedoed the first vessel in Gulf 

waters on May 4, 1942 when she sankthe freighter Norlindo off Key West, Florida (Wiggins, 

1995). Norlindo’s sinking unleashed a wave of destruction in the GoM. Korvettenkapitän Harro 

Schacht’s crew aboard U-507 sank eight vessels in the GoM, making it one of the most successful 

U-boats in this theater of war. U-507’s fourth victim was the cargo freighter, Alcoa Puritan. U507 also sank the tanker, Virginia on May 12 (Schacht 1942: 13, 32, 52). In May 1942, a second 

U-boat U-506 joined the Gulf campaign, sinking the tankers, Gulfpenn on May 13 and Halo on 

May 20, and six other merchant vessels (Würdemann 1942: 12, 22, 30).

By July 1942, the United States increased efforts to protect shipping in southern waters. Coastal 

lights were shut off, lighthouse beacons were dimmed, and strict information blackouts enacted. 

Aerial reconnaissance and radio listening posts helped American naval and Coast Guard units track 

the U-boat threat. Merchant vessels were ordered to travel in convoys with naval escorts. These 

efforts diminished the number of vessels sunk by U-boats by August 1942 and turned the tide of 

the U-boat threat in American coastal waters. 

U-166, commanded by Kapitänleutnant Hans-GüntherKühlmann, joined the fray in July, 1942. U166 took position off the Mississippi River’s mouth in operational area DA-90. The U-boat’s 

mission was to lay mines and attack merchant shipping (War Diary 1942: 36, 53, 92; and Blair 

2000: 633). Although the nine TMB mines were successfully laid only a few hundred yards off 
354

the jetties in the Southwest Pass of the Mississippi River, none detonated. TMB mines were 

shallow-water German torpedo-launched mines that sat on the seabed and were activated by the 

magnetic or acoustic signature of a passive ship. Kühlmann sank the passenger freighter SS Robert 

E. Lee approximately 45 miles southeast of the Mississippi River on July 30, 1942. PC-566, the 

naval vessel escorting the freighter, then sank U-166 (Blair 2000: 633; and USS PC-566 1942). 

Deep water and conflicting first-hand accounts from 1942 hid U-166’s actual location for nearly 

60 years. Although 75 percent of all U-boats were sunk by the war’s end, only one (U-166) was 

lost in the GoM.(Blair 2000:704). 

The German U-boat freely hunted these waters until late 1942, when American antisubmarine 

measures improved and helped turn the tide (Blair 2000: 696). By May of 1943, twenty-four 

German U-boats had entered the Gulf. Seventeen U-boats sent 56 merchant vessels to the bottom 

and badly damaged 14 others (Church et al. 2002). For those 56 ships, the American response to 

German U-boat attacks in the GoM came too late. Hundreds of merchant mariners lost their lives 

and ships to German torpedoes. Many tankers became floating bombs when torpedoes ignited the 

petroleum products in the holding tanks, leaving the crews either entombed in a fiery hull, or afloat 

in the blaze. The GoM war zone was a submerged and surface war front for military and nonmilitary vessels alike. 

10.3.3 Oil and Gas Development and Shipwreck Discovery

The oil and gas industry supports the largest percentage of commercial marine surveys in the GoM

by far. The increased interest in developing deepwater oil and gas prospects has also led to 

significant advances in marine survey technology and equipment such as sophisticated deep-tow 

survey systems, improved Remote Operated Vehicle (ROV) technology, Autonomous Underwater 

Vehicles (AUV), and precision acoustic positioning systems. The development and use of these 

systems has facilitatedthe identification of potentially significant shipwrecks, biological life forms, 

and geological formations. The increased deepwater oil and gas exploration in the Gulf’s 

deepwater areas has also increased shipwreck discoveries. The shipwrecks investigated for this 

study were found on oil and gas related surveys. Further significant discoveries can be expected 

as the search for natural resources moves into increasingly deeper waters.

10.3.4 Regulatory Role of the BOEM and BSEE

Increases in deepwater oil and gas exploration, development, and production coexist with the 

development of new technologies that reduce the operational costs and risks associated withthe 

discovery of high-volume oil and gas reserves.

Expanding deepwater commercial development brings increasing challenges for managing 

Submerged Cultural Resources on the OCS and shelf slope. The BOEM requires a clearer 

understanding of the size of debris fields that can be expected around deepwater wrecks, as well 

as their state of preservation and research potential to fulfill obligations stipulated by Section 106 

of the National Historic Preservation Act of 1966 (36 CFR 800). This information is critical for 

determining disturbance avoidance areas. Part 36 CFR 800.4(c) states that “the Agency Official 
355

shall make a reasonable and good faith effort to identify historic properties that may be affected 

by (an) undertaking and gather sufficient information to evaluate the eligibility of these properties 

for the National Register.” Sufficient documentation must be provided to the BOEM on each site 

to carry out an adequate evaluation of National Register of Historic Places (NRHP) criteria (USDI 

MMS 2004).

The former MMS played an instrumental role in the development of the Rigs-to Reefs program in 

the GoM. The Agency’s efforts led to the National Fishing Enhancement Act of 1984 and 

publication of the National Artificial Reef Plan in 1985. Converting offshore oil and gas structures 

is well accepted as beneficial to fisheries on the continental shelf of the entire GoM (Ekins P., et 

al, 2006). Forty-nine (49) structures have been converted to artificial reefs from a total of 383 

structure removals between 1999 and June 2002. In the near future, decisions will be required for 

the removal of structures located in waters beyond the continental shelf. Current guidelines 

outlined in 30 CFR Part 250.1728 allow the BOEM Regional Supervisor to approve alternate plans 

for removal of structures when the water depth is greater than 800 m (2,624 ft). Removal options 

for shallower depths have previously relied on the concept that the structure left behind serves a 

positive fisheries enhancement or other beneficial environmental function. The BOEM now 

requires information that will help describe the ecological role (if any) man-made structures may 

have in the deepwaters of the GoM (in this case, greater than 91.4 m (300 ft) (USDI MMS 2004).

10.4METHODS

10.4.1 Survey Methodology

Each site was systematically investigated using an acoustically positioned ROV following a preestablished survey plan (See Section 10.4.2.1 Archaeological Methods). The ROV survey was 

designed to maximize the efforts and time for both the archaeological and biological studies. It 

carried the necessary equipment (See Section 4.1.2) to obtain high-quality imagery, accurately 

measure artifacts and biological organisms, and document seafloor conditions or features. 

Detailed visual inspections provided needed data to document each wreck’s cultural and biological 

characteristics. Although different specific elements were of interest to the biologists and the 

archaeologists, the video footage collected was used for both the biological and archaeological 

studies undertaken.

A minimum of one archaeologist and one biologist were available at all times to ensure important 

features were not missed. Video footage was recorded continuously during ROV operations at 

each site and digital still photographs or screen captures were taken of pertinent archaeological 

and biological features.

10.4.2 Archaeological Methods

10.4.2.1 Field Methods

Standardized investigation methods were used at each study site. The archaeologist’s priorities 

varied depending on whether previous inspections had positively identified the shipwreck. At 

previously un-investigated shipwreck sites, the first priority was determining the historic potential 
356

of the site, mapping the site boundaries/extent, and producing an accurate site plan. At previously 

identified shipwreck sites, the priority was mapping the site boundaries/extent and producing an 

accurate site plan. Site maps were produced using real-world coordinates to allow importation 

into a GIS database.

The investigation methodology used all available information and survey data for each site to plan 

field operations. The survey data included side-scan sonar, magnetometer, subbottom profiler, 

bathymetric data, AUV camera footage, and video footage. Previously acquired survey data was 

essential for determining the “expected” boundaries of each site and for developing an efficient 

survey plan. At each shipwreck site, the investigations followed the same pattern of 

reconnaissance, mosaic photography, biological sampling, close-up photography, and artifact 

recovery.

10.4.2.1.1 Reconnaissance Transects

After the ROV was deployed, a reconnaissance survey of the main wreckage was conducted. The 

reconnaissance allowed the science team to assess the current conditions of the wreck site and 

aided them in determining where to collect samples and place the microbial experiments. For the 

reconnaissance survey, the ROV slowly moved down each side of the hull (outboard of the 

gunwale) to inspect the outer hull (where applicable) and the material on the seafloor near, but 

outside of the hull. Then the ROV moved inboard to view the inner hull and contents (at some 

sites it was necessary to only make one pass along the side). Time was also spent thoroughly 

inspecting the bow and stern areas.

10.4.2.1.2 Mosaic Transects

The mosaic transects were comprised of a series of closely spaced parallel ROV lines. They were 

designed to allow Jason II’s downward looking digital still camera to capture overlapping images 

of the wreck site. A mosaic of these images was produced to form a single image encompassing 

the entire wreck site. If mosaics from previous surveys, such as an AUV camera survey, were 

available, the ROV mosaics were limited in scope to significant areas of the wreck as determined 

by the archaeological team.

10.4.2.1.3 Biology Transects

Biology transects documented the sea life near and away from the wreck site. The survey consists 

of two sets of predetermined survey lines consisting of three parallel transects, 50 m long, and 

spaced 10 m apart (line spacing depended on conditions at each site). One set of transects ran over 

the long axis of the wreck at an altitude that allowed good visual documentation of the wreck. The 

second set was run in the same pattern 100 m away from the wreck. 

Core samples were taken near the wreck site and away (100 m) from the wreck. The cores were 

taken in pairs for collection consistency and to expedite this task.

Microbial platforms were placed at each site. These are long-term experiments to analyze the

microbial activity and rate of hull deterioration at each site. 
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10.4.2.1.4 Close-Up Transects

Close-up inspections included detailed photography and documentation of specific corals or other 

areas of biological interest (e.g., rusticle formations), and specific areas of archaeological interest 

(e.g., specific artifacts or areas of hull construction.). The archaeologists and biologists conducted 

these operations in conjunction with each other or split the time, depending on the varying interests 

at each site. 

10.4.2.1.5 Artifact Recovery

Limited diagnostic artifacts were recovered at each site upon instructions of the principal 

archaeologist and in consultation with the BOEM archaeologist. The materials recovered from the 

wreck sites for identification and dating purposes included: copper sheathing, wood, ceramics, and 

shipboard equipment.

10.4.2.2 Post-Field Operations Archaeological Data Assessment

Following each period of field operations, all the digital data was brought to the C&C’s Lafayette 

or Houston offices. Once at C&C, a backup copy of the data was produced for the data archive, 

then additional copies of each dataset were provided to C&C’s archaeological staff. The data was 

then assessed by the archaeologist assigned to each shipwreck site. Assessment of the collected 

data included review of video and still footage to document the pertinent construction attributes, 

ship components, artifacts, etc., followed by examination of field notes and historical research.

For each shipwreck assessment, standard descriptions and definitions related to ship construction

(Figure 10-6) and documentation were used. Overall site dimensions and distances are discussed 

using metric measurements. Specific construction details of each of the vessels are described using 

the measurement units most likely used during construction. In the case of the Gulfpenn, Gulfoil, 

and the four wooden shipwrecks, this was assumed to be English measurements. In the case of 

the U-166, metric measurements were used based the location and date of its construction.
358

Figure 10-6. An example of double-framed construction illustrating ship construction 

terminologies used in this report.

10.4.3 Conservation Methods

10.4.3.1 Field Conservation

The recovered artifacts were placed in plastic containers filled with seawater, and kept submerged 

in an environment similar to where they were recovered. Some field photos were taken, but with 

the movement of the ship, most details were blurry. Current photos of each artifact were taken in 

the lab. Any of the objects that may have been light sensitive, such as the paper in the compass, 

were kept covered as much as possible to reduce damage. Artifacts were protected with foam 

mattress padding during transport from the ship to the University of West Florida Conservation 

Laboratory. 

10.4.3.2 Laboratory Conservation

For every artifact, the first step of the conservation process was to photograph and document the 

artifact. The next step was the removal of chlorides from the artifact. An object immersed in salt 

water absorbs salt chlorides from the water. If the chlorides are still in the artifact as it dries, 

serious damage can occur. Chlorides are removed by soaking artifacts in successive tap water 

baths until the chloride level has been lowered to below 100 parts per million. Once the chlorides 

have been removed, the conservation process, which is dictated by artifact type, can proceed.
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A detailed description of the conservation methods employed in stabilizing and conserving the 

artifacts recovered during the project is provided in the University of West Florida Conservation 

Report found in Appendix E-2

10.5SHIPWRECK SITE ASSESSMENTS

10.5.1 Viosca Knoll Wreck Site

10.5.1.1 Historical Background of the Viosca Knoll Wreck

The Viosca Knoll Wreck Site is the remains of a wooden sailing vessel dating from the latter 

nineteenth century. Discovered in 2003 during an archaeological, engineering and hazard pipeline 

survey, the wreck was named for the lease block area where it was found. Archival research has 

failed to identify the name or nationality to this shipwreck. Since its discovery, a deep-tow and 

AUV survey and two government sponsored ROV investigations have been conducted at the site.

10.5.1.2 Field Investigations

10.5.1.2.1 Discovery and Exploration

In 2003, a pipeline survey for Mariner Energy discovered the unidentified shipwreck south of the 

Petronius platform. The survey used a deep-tow AMS 120 Sonar Mapping System, which 

included 120 kilohertz (kHz) side-scan sonar. The wreck was outside the pipeline survey corridor, 

but was imaged during a line turn. Several additional investigation lines were run over the site to 

obtain additional geophysical data (Church 2003). In May 2004, C&C conducted an AUV survey 

of the shipwreck site using C-Surveyor I. High-resolution multibeam bathymetry and side-scan 

sonar data were collected on 27 survey lines crisscrossing the site. The side-scan sonar showed 

debris scattered west and southwest of the shipwreck (Figure 10-7). Numerous drag scars, 

characteristic of those caused by large anchor chain and cable, were also noted in this sonar data. 

One drag scar crosses the wreck’s northern end (Figure 10-8). An elongated seafloor depression 

or large drag scar exists east of the wreck (Figure 10-9 and Figure 10-10). The southeast portion 

of the wreck (port side) exhibits an average of 2 m of relief with the stem post standing 

approximately 3.3 m high (Church and Warren 2008).
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Figure 10-7. Side scan sonar image of the VK Wreck and surrounding area (courtesy of C & 

C Technologies, Inc.).
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Figure 10-8. Side scan sonar image, close-up of the VK Wreck (courtesy of C & C 

Technologies, Inc.).
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Figure 10-9. North-up plan view of the VK Wreck. Processed multibeam image at 1.5-foot bin 

size (Courtesy of C & C Technologies, Inc.).

Figure 10-10. A 3-D perspective view of the VK Wreck. Processed multibeam image at 1.5-foot 

bin size (courtesy of C & C Technologies, Inc.).
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10.5.1.2.2 Viosca Knoll Wreck 2006 ROV Investigation (OCS Study MMS 2008-018)

A site investigation was planned during the 2004 fieldwork for the MMS’s Archaeological and 

Biological Analysis of World War II Shipwrecks in the Gulf of Mexico (OCS Study MMS 2007-

015), but adverse weather made investigating the site impossible at that time (Church et al. 2007). 

The MMS later sponsored a site investigation in July 2006 (OCS-Study MMS 2008-018). The site 

was visually inspected used a Saipem American Innovator Class ROV deployed from the HOS 

Innovator. The investigation was conducted under the direction of C&C marine archaeologist 

Robert Church and BOEM marine archaeologists Jack Irion and David Ball (Church and Warren 

2008). Visibility on-site was poor during the 2006 investigation, averaging only 2.4 to 3.6 m. The 

ROV position was continually recorded (at 6 second intervals) using a Sonardyne USBL System.

The entire investigation was conducted in approximately 6 hours and began with a site 

reconnaissance followed by photo mosaic transect lines. A photo mosaic was produced using 

screen captures from the ROV’s video camera. The mosaic lines consisted of eight transects run 

over the wreck site on a heading of 35 degrees and an equal number of reciprocal lines run on a 

heading of 215 degrees. Line spacing was less than 2 m to ensure visual overlap. Detailed visual 

inspections of specific areas of interest were conducted upon completion of the mosaic lines. The 

final part of the survey was the visual inspection of outlying debris noted from the geophysical 

data and/or detected with the ROV’s scanning sonar during the site investigation. 

10.5.1.2.3 Lophelia II: Reefs, Rigs, and Wrecks 2009 Field Cruise

In September 2009, the second ROV investigation of the Viosca Knoll Wreck was conducted as 

part of the Lophelia II: Reefs, Rigs, and Wrecks Study. Over an approximate 12-hour period (10.5 

hours on the wreck site) on September 5 and 6, 2009, the Lophelia II team used Woods Hole 

Oceanographic Institution’s Jason II ROV launched from the NOAA Research Vessel Ronald H. 

Brown to document the shipwreck site. Visibility on-site was fair during the 2009 investigation, 

averaging 6 to 7 m. Limited material was collected during the project to help better understand 

the wreck site.

The 2009 investigation consisted of an initial reconnaissance survey, site mosaic transects, detailed 

inspection of significant features (both biological and archeological), deploying biological 

experiments, and artifact collection. The one hour reconnaissance consisted of a preliminary 

examination around the full perimeter of the main hull to assess its current condition and to 

prioritize areas for additional investigation and material collection. The reconnaissance began on 

the port side at the bow and moved slowly along the port side toward the stern. After an 

examination of the stern, the ROV moved along the starboard side towards the bow. The ROV 

then moved inboard with a starboard view and slowly transited back toward the stern, videoing the 

interior of the hull. 

Following the reconnaissance, 19 parallel track-lines at 1 meter spacing were flown over the main 

hull, taking a series of evenly spaced still photographs for mosaic purposes. The digital still camera 

was mounted in a vertical viewing position and the ROV was flown at a 6-m altitude during 

transects. Approximately three hours were spent conducting the photo mosaic transects.
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Biological operations were conducted over the next three and a half hours, including biological 

transects, collecting sediment cores, deploying microbiological experiments, and detailed 

biological documentation. Three biological transects were run 100 m southeast of the wreck site. 

Sediment core samples were collected at distances varying from 100 m away to 10 m from the 

wreck site. Short-term and long-term microbiological experiments were placed on the aft portion 

of the wreck to assess microbial activity and preservation potential. Detailed photographs and 

measurements were taken of coral and other features of biological interest at the bow and along 

the port side of the wreck.

Following the biological investigation, close-up examination was conducted of archaeological 

features in conjunction with limited artifact recovery and recovery of the short-term 

microbiological experiment. Approximately one and one-half hours was allocated for those tasks. 

The remaining 2 hours of the dive included investigation of outlying artifacts and preparations for 

ROV recovery. The archeologists and biologists concurrently conducted the detailed examination 

of the outlying artifacts.

10.5.1.3 Geographic Settings

The Viosca Knoll Wreck is in the southeastern portion of the Viosca Knoll Area of the GoM

(Figure 2-2). The project area is located south-southeast of Mobile, Alabama on the upper 

continental slope. The seafloor dips south-southeast across the site at a gradient of 5 degrees. 

Very soft clays are the predominate near-seafloor soils at the site. The Alabama River provided 

sediment input into this area prior to and subsequent to the sea level low stand, which occured 

about 18,000 years BP. Sediment input into this area was highest when the St. Bernard delta was 

active between 1,500 and 4,000 years BP (Frazier, 1967). Sedimentation rates for the area became 

much lower as the Mississippi River deltas and lobes migrated southwest. The deeper stratigraphy 

in the region is influenced by the upper eastern Mississippi Fan which was fed through submarine 

canyons or channels originating on the upper slope (Dixon and Weimer, 1998).

10.5.1.4 Discussion of Archaeological Findings at the VK Wreck

10.5.1.4.1 Physical Site

The vessel is oriented with the bow pointing southwest and the stern northeast (Figure 10-11). 

Average water depth at the site is 612 m Below Sea Level (BSL). The vessel measures between 

121.3 to 141 ft (37 to 43 m) long and approximately 26 ft (8 m) at the beam. It is estimated the 

vessel had an approximate 5:1 length-to-beam ratio. It is not possible to get an exact measurement 

with the currently available data because the stern is not intact and the vessel is listing to starboard. 

Individual artifacts, rigging and other hull material are scattered primarily out from the stern, bow, 

and starboard side making the overall measurement of this portion of the site 47×19 m. A few 

additional outlining artifacts are located as much as 143 m west-southwest of the hull making the 

overall site dimensions 188 × 67 m.
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Figure 10-11. Viosca Knoll Wreck Site Drawing based on ROV investigation findings.

The wreck’s starboard side is mostly flush with the seafloor, while the port side exhibits between 

3.3 and 6.6 ft (1 to 2 m) relief, exposing the turn of the bilge. The hull is listing approximately 41 

degrees to starboard, based on the angle of the stempost (Figure 10-12). Marine sediments and 

biofouling obscure much of the construction details, but some inferences can be made regarding 

hull construction. Remnants of the frames, and possibly the wale, and clamp are visible at some 

locations along the port side. The construction appears to be double framing. The frames, at what 
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is believed to be the second and third futtocks, are approximately 7.5 in (19 cm) sided and 6.5 in

(16 cm) molded. The room and space is approximately 8 to 9 in (20 to 23 cm). The hull planking 

measures approximately 8.6 in (22 cm) wide and 1.5 to 3.5 in (4 to 8.9 cm) thick where discernible 

on the starboard side.

Figure 10-12. Front view of stem post showing list to starboard.

10.5.1.4.2 Sheathing

The hull of the Viosca Knoll Wreck is sheathed primarily in Muntz metal and although some nonuniform lengths may have been used, the majority of sheathing appears to be standard 48 × 14 inch 

(121.9 × 35.5 cm) sheets with 1 to 1.5 in (2.5 to 3.8 cm) overlap between sheets (Figure 10-13). 

The sheathing is held to the hull by copper or copper alloy fasteners, which are staggered between 

rows forming a typical diamond nail pattern. The fasteners spacing is 5.25 in (13.3 cm) between 

nails horizontally and 3.5 in (8.9 cm) diagonally. Diagonal foiling (buckling) is observed along 

the copper or copper alloy sheathing, which is typical for copper-sheathed vessels found in deepwater (Figure 10-14). The reason the sheathing becomes buckled is not fully known, but is 

possibly related to either compression of the wood at depth or anaerobic bacteria activity. DBI 

tested a section of new copper sheathing in a laboratory experiment and observed buckling of the 

sheathing after six months. (Appendix E-1). The foiling likely occurs in a diagonal pattern on the 

shipwreck because of the diagonal nail pattern holding the sheathing to the hull.
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Figure 10-13. Sheathing detail from starboard side.

Figure 10-14. Diagonal foiling observed in sheathing (Starboard side).
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10.5.1.4.3 Bow

The stempost remnant stands approximately 10.8 ft (3.3 m) proud of the seafloor (Figure 10-15). 

The upper remnants of the stem measure 10 in (25.5 cm) molded and 6 in (15.2 cm) sided. A 

portion of apron or inter-stem is visible (Figure 10-16). The rabbet appears to be visible on the 

stempost exposing the juncture of the hull strakes. It was not possible to accurately measure the 

lower portions of the stem (above the sheathing) because of substantial biological growth. The 

front edge of the sheathed cutwater measures 4 in (10.1 cm) wide. The bow appears to gently 

round from the keel to the apparent water line. Possible remains of the gammon irons and head 

rigging lie beneath the stempost (Figure 10-17). A small section of thin net is visible on the 

seafloor forward of the bow (Figure 10-18). The net is likely intrusive to the site. Various other 

construction features were observed including disarticulated knees and possible cant frames. No 

windlass or anchor chain was observed at the wreck site. 

Figure 10-15. Mosaic of the bow (view from port side).
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Figure 10-16. Close up profile of upper stem remains.

Figure 10-17. Gammon irons and head rigging.
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Figure 10-18. Image of net remnants on the seafloor near the Viosca Knoll Wreck’s bow.

10.5.1.4.4 Stern

The aft portion of the wreck is badly deteriorated and shows damage consistent with possible cable 

impact to the hull. A 0.5-to-1-meter tear in the hull’s starboard side is visible approximately 14 m

forward of the stern and 26 m aft of the stem (Figure 10-19). This damage correlates to a seafloor 

drag scar recorded on the geophysical survey data. The drag scar crosses the wreck at an 

approximate 29-degree angle. The location where the drag scar crosses the hull likely corresponds 

with the possible mainmast position. Aft of the drag scar, most of the stern is missing or damaged. 

Some of the exposed wood structure in the stern exhibited much less deterioration than the other 

wood material at the site, indicating possible recent exposure. 

A portion of the rudder appears to remain in place with a possible loose gudgeon laying exposed 

on the seafloor less than 2 m away (Figure 10-20 and Figure 10-21). The rudder measures 7.5 in

wide (19 cm). Only one meter of the rudder is exposed above the seabed and the upper portion is 

broken away. It is not known how much of the upper portion of the rudder is missing. The width 

of the possible gudgeon is also approximately 7.5 in (19 cm).
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Figure 10-19. Image of the Viosca Knoll Wreck showing the tear in the port hull.
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Figure 10-20. Copper-sheathed rudder of the VK Wreck with close-up inset showing a portion 

of the pintle (10 cm laser scale shown at bottom of inset).

Figure 10-21. Possible Gudgeon strap lying on the seafloor at the stern of the VK Wreck.
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Two ingots of possible lead, based on its whitish color, are laying on the seafloor at the stern, as 

are numerous other unidentified ship parts and objects. The ingots measure 14 in (36 cm) long 

and 2 in (5 cm) wide. One is at the end of the stern and the other is near a large metal ring on the 

starboard side of the stern remains. The metal ring is possibly brass, copper, or copper-alloy and 

is lying on top of the other stern debris (Figure 10-22). The interior diameter of the ring is 29.5 in

(75 cm) and it is 4.3 in (11 cm) thick. A 6.5 foot (2m)section of metal shaft appears to be attached 

to the top of the ring. The function of the ring is not known, but may be associated with a mast 

such as a gaff head-ring. 

Figure 10-22. Starboard side view of the VK Wreck’s stern showing possible gaff head-ring, 

ingots, water filter on the right side of the image, and rudder in the background.

Approximately 1.5 m forward of the ring and shaft was the lower portion of a ceramic water filter 

(Figure 10-23). The filter was originally thought to be an earthenware crock until it was recovered. 

Nearby are what appear to be eight or more charcoal replacement filters. They are arranged sideby-side in two rows as if once in a box or bound together. The packaging of the replacement filters 

have mostly disintegrated. A ceramic disk with holes sits on it’s edge less than two m forward of 

the filter along the starboard side (Figure 10-24). The ceramic disk appears to be the disk that once 

separated the chambers in the filter. 
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Figure 10-23. Water filter and replacement charcoal.

Figure 10-24. Ceramic disk, which is likely part of the water filter.
375

10.5.1.4.5 Rigging

A coil of line or wire rope is located along the starboard side 8 to 9 m forward of the stern (8.6 m

forward of the ring and shaft). The drag scar that crosses the wreck missed the coil of line by 

approximately 4 m. No other rigging is visible near this portion of the hull although rigging from 

the main mast should be present near this location.

A substantial amount of apparent foremast rigging is present along the starboard side of the hull. 

A 24.6 foot (7.5 m) section of large standing rigging (possibly a main stay) lies along the seafloor 

adjacent to a portion of chainplate (Figure 10-25). The standing rigging is approximately 4 in

(10.1 cm) in diameter. A broken section of rigging also lies inside the hull at a 47-degree angle to 

that lying on the seafloor and may represent another section of the same standing rigging. The 

rigging within the hull passes through several large rigging eyes. A mast cap is visible as well as 

a possible masthead block within the rigging lying on the seafloor. The chainplate remains and 

visible portions of standing rigging are possibly from the vessel’s port side. As the mast eventually 

fell to starboard with the list of the vessel, the port side rigging would have pulled away from the 

deteriorating hull and fallen to the seafloor landing on the starboard side of the hull. When the 

ship’s mast deteriorated, only the rigging remained to mark its location. The rigging in this area 

of the site does not appear to have been disturbed after settling to the seafloor. The location and 

orientation of the rigging indicates it is the foremast rigging, which fell back and to the starboard 

side. 
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Figure 10-25. Mosaic of the VKE Wreck’s foremast rigging, showing mast cap, chain plate, and 

possible masthead block.
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Based on the amount of extant rigging, and the placement and the size of the rigging, the vessel 

appears to have been two-masted. The most likely vessel types for a two-masted vessel of this 

size are either a brig or schooner. Typical proportions for a brig or two-masted schooner places 

the foremast 1/4 or less of the total length from the stem and the main mast approximately 3/5 of 

the total hull length from the stem. These are the typical proportions; however, these dimensions

are not set in stone. The foremast in both brigs and schooners were often less than a 1/4 of the of 

the hull’s total length from the stem. The main mast, though less common, may be less than 3/5 

of the hull’s total length from the stem (Smith 2005, Chapman 2006, Steffy 1994, and Rybka and 

Moreland 1994).1 If the 40-meter long Viosca Knoll Wreck followed the traditional layout, the 

foremast would have been approximately 10 m aft of the stempost and the main mast 

approximately 24 m aft of the stempost. 

10.5.1.4.6 Deck Beams Other Construction features

Numerous deck beam remnants are visible within the hull. The deck beams appear to be on 4-foot

centers, but are spreading apart at various locations. Lodge knees and hanging knees are visible 

at various locations within the hull. Near amidships are the remains of deck beams associated with 

intact carling and lodging knees (Figure 10-26 and Figure 10-27), which are visible on the 

starboard side of the vessel. This extant deck structure indicated the lower hull is likely intact 

below the silt covered deck. If the lower hull is intact, cargo and other contents may have survived 

in this area.

Figure 10-26. VK Wreck’s deck structure from starboard view showing deck beams and lodging 

knees.

 

1 Ship dimensions and construction information were compiled from documentation on the Brig Frolic; the U.S. Navy 

Brigs Jefferson, Eagle, and Niagara; and Fredrik Henrikaf Chapman’s substantial drawings of brigantines and 

schooners.
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Figure 10-27. Deck structure detail in plan view (drawing by Robert A. Church).

10.5.1.4.7 Scattered Artifacts - Outlying Material

A mass of rigging, including a mast cap, is located 142 m west-southwest of the hull. This may 

be rigging from the main mast, which is notably absent at the hull. The rigging covers an area 

measuring 11 × 6 m. A section of possible quarter-inch polypropylene rope appears to be tangled 

in the rigging. It is not known whether the “polypropylene” became associated with the rigging at 

the time it was displaced or if it was intrusive to the site. A possible ceramic cup or insulator is 

lying beside the mast cap and a section of possible standing rigging chain (the chain links measure 

approximately 1.5 in (4 cm) long). The object is white in color, concaved in the middle, and 

measures 3.5 in(9 cm) tall. It is approximately 3 in in diameter on the ends, narrowing to 2.4 in in 

the middle (7.5 cm in diameter, narrowing to 6 cm in the middle) (Figure 10-28).
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Figure 10-28. Rigging away from VK Wreck’s main hull and possible ceramic cup or insulator 

located near mast cap.

A line of other debris was observed between the hull and this rigging. The largest outlying artifact 

observed is a patent stove standing upright in a seafloor depression (Figure 10-29). It measures 

approximately 30 in (77 cm) wide and 26 in (65 cm) deep. Although the details are obscured by 

sediment and biofouling, a raised lip is visible around the edge. Marine stoves often had a raised 

lip or band around the top edge to keep pans from sliding off the surface while at sea. Accurately 

estimating the stove’s height was not possible because of the angle of view and the fact that the 

feet are partly embedded in the seafloor, but it stands at least half a meter above the sediment. The 

stove is located 74 m west-southwest of the hull.

A possible lantern (Figure 10-30) and an unidentified object (Figure 10-31) were also documented 

63 m west-southwest and 38 m south of the hull, respectively. The lantern is lying on its side. It 

measures approximately 18 in (45 cm) in height and 12 in (30 cm) in width. The viewing glass is 

not visible and may have fallen inside the body or is missing. The unidentified object measures 

approximately 18 in (45 cm) in diameter and is covered with biofouling.
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Figure 10-29. Patent stove found away from main hull.

Figure 10-30. Lantern away from main hull at VK Wreck site (2006 image, MMS 2008-

018).
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Figure 10-31. Unidentified object away from main hull at VK Wreck site (2006 image, MMS 

2008-018).

10.5.1.5 Recovered Artifacts

Two artifacts, a ceramic water filter and sample of metal sheathing, were recovered from the 

Viosca Knoll Wreck site during the 2009 investigation. The artifacts were conserved at the 

University of West Florida (UWF) Archaeology Institute’s conservation lab in Pensacola, Florida 

and the conservation report can be found in Appendix E-2

The water filter (Artifact: MMS09.15303.C.001) is salt glazed stoneware and only consists of the 

lower portion of the filter. The upper portion of the filter was not found during the investigation. 

The filter was recovered from the aft starboard side of the shipwreck. The recovered portion of 

the filter measures 21 cm in diameter and 15 cm in height. It features a decorative fern leaf motif 

to each side of the spout opening at the bottom. The words “Water Filter,” “Corporation St.,” and 

“Manchester” are written above the spout (Figure 10-32). The spout was separated during 

recovery and rejoined in the conservation lab.
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Figure 10-32. VK Wreck’s Water filter after conservation.

Such filters were common in the later nineteenth century because diseases like cholera and typhoid 

were linked to impure water supplies. By 1863, Slack & Brownlow was manufacturing charcoal 

filters in Manchester England and by 1876 had competition from William M. Jowett & Co. The 

filter recovered from the Viosca Knoll Wreck matches the style and design of portable filters 

manufactured by William M. Jowett & Co., located at 75 Corporation Street in Manchester 

between 1876 and 1884 (Figure 10-33). They produced and sold compressed charcoal filters for 

ships and steamboats. An 1876 advertisement lists the company as the successor to the Messrs. 

G. Busse and Co. and the “sole manufacture of their Improved Royal Patent Prize Medal Charcoal 

Block and Loose Charcoal Rapid Water Filters; manufacturers to the Admiralty...” (Slater’s 1863-

1884). The water filter recovered from the Viosca Knoll Wreck is likely the lower quarter of a 

Jowett & Co. filter providing a possible terminus post quem of 1876 for the shipwreck.
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Figure 10-33. An 1882 advertisement in Export Merchant Shippers showing a Jowett & Co. 

Water Filter.

The sample of metal sheathing (Artifact: MMS09.15303.M.002) was recovered from the seafloor 

near the damaged area on the aft port side of the wreck. It is a single strip of sheathing measuring 

44.5 cm long and 11.5 cm wide (Figure 10-34). Field observation indicated the metal is copper or 

copper alloy. A portable X-Ray Fluorescence analyzer was used at the UWF conservation lab to 

identify the exact metal type. The results of the X-Ray Fluorescence analysis showed the metal is 

composed of 65.57% copper, 28.61% zinc, 2.68% lead, 1.95% iron, 1.09 tin, and 0.1% other 
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metals. The X-Ray Fluorescence results indicate a copper: zinc ratio of 1:44. A sample of the 

metal sheathing was also sent to DBI’s lab in Saskatchewan, Canada and the full microbiology 

wreck report can be found in Appendix E-1. The sample was tested at the Saskatchewan Research 

Council laboratory using Inductively Coupled Plasma Atomic Emission Spectroscopy. The test 

indicated a copper: zinc ratio of 1:59. Although the test at UWF and DBI resulted in slightly 

different ratios, they both indicate the sample is likely Muntz Metal and is consistent with late 

nineteenth century sheathing. 

Figure 10-34. Muntz Metal Sheathing from the Viosca Knoll Wreck.

10.5.1.6 Site Preservation

The VK Wreck site is currently in a moderate state of preservation. The hull is partially intact 

where it is sheathed. The sheathing’s anti-biofouling properties likely offer some protection to the 

hull sections in direct contact with it. This is consistent with other GoM deep-water discoveries, 

where wooden hull remains are present in conjunction with copper sheathing and is largely absent 

above the line of sheathing. The bow is partly intact, but the stern is heavily damaged, most likely 

from post sinking and anthropogenic disturbance. The vessel is heeled over to starboard, leaving 

much of the deck area and port side exposed. Since the starboard side is mostly buried, an accurate 

assessment of its preservation state cannot be made, but it is likely that it has been protected by 

the seafloor sediments and remains relatively intact.

In an effort to monitor the wreck’s preservation, a short-term etching microbial tester and longterm Wooden Wrecks General Underwater Corrosion Coupon Instruments (WW-GUCCI) 

platform were deployed at the site to test microbial activity and monitor deterioration rates (Figure 

10-35). The etching tester was not left in place long enough for a reaction to occur and to provide

information on the level of microbial activity at the site. The WW-GUCCI platform, deployed 

near the stern of the wreck, is designed to provide a long-term indication of site deterioration rates 

from microbial and chemical deterioration. Reexamination of the test platform in the future will 

be invaluable in assessing long-term preservation of the Viosca Knoll Wreck site.
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Figure 10-35. WW-GUCCI Microbial Test Platform being deployed near the port stern.

10.5.2 7,000 Foot Wreck Site

10.5.2.1 Historical Background of the 7,000 Foot Wreck

The 7,000 Foot Wreck is the remains of a sheathed wooden hull sailing vessel. The wreck was 

discovered during an oil and gas exploration of the Mississippi Canyon Area in 1986. The wreck 

is named for the major bathymetric contour nearby. The original name and nationality of this 

vessel remain unknown. Since its discovery in 1986, there have been two AUV surveys and one 

ROV investigation of this site.

10.5.2.2 Field Investigations

10.5.2.2.1 Discovery and Exploration

In 1986 a deep tow survey being undertaken as part of an oil and gas exploration program 

documented a possible target in the Mississippi Canyon area. The target was described as an 

“elongated, apparently solid, oval sonar contact 27 m in length and 11 m in width” (Pearson, et. 

al). In 2005, when the entire Mississippi Canyon area was designated an archaeological highprobability region, the wreck site was reported to the MMS Social Sciences Unit and was 
386

determined to be a potential shipwreck site. A 2,000-foot radius archaeological avoidance zone 

was established around the wreck site by the MMS.

In 2006, Shell Exploration and Production Inc. (Shell) was exploring the deep waters of the 

Mississippi Canyon area for potential oil and gas exploration in the same region as the 1986 survey. 

Shell contacted C & C Technologies, Inc. to conduct a geophysical survey of the area using C&C’s 

C-Surveyor IITMAUV system. Since the entire Mississippi Canyon area had been designated as an 

archaeological high-probability area in 2005, the survey included an archaeological assessment.

The planned survey covered the area of the potential shipwreck located on the 1986 deep tow data. 

Because of the presence of a previously discovered shipwreck in the area, a series of highfrequency (430 kHz) side-scan sonar investigation lines were planned as part of the overall survey. 

A review of the geophysical data by a C&C marine archaeologist confirmed that the target was a 

shipwreck site. The AUV side-scan data indicated the wreck site is 23 m long and 6 m wide, with 

1 meter of seafloor relief (Warren, 2006).

The high-frequency geophysical data from the 2006 AUV survey indicated that the 7,000 Foot 

Wreck was likely a wooden sailing vessel (Figure 10-36). The intact nature of the wreck suggested 

it was copper sheathed. An area of lighter reflectivity noted in the geophysical data along the 

starboard side of the vessel was interpreted as resettled sediments that were disturbed during the 

wrecking process. No debris trails were noted extending out from the wreck. A linear feature 

extending off the bow area of the wreck was thought to be mast or rigging remains. The subbottom 

data indicates that as much as 1.8 m of the wreck could be buried beneath the seafloor.

Figure 10-36. Multibeam backscatter mosaic image of 7,000 Foot Wreck from data collected by 

the ABE Sentry AUV (Woods Hole Oceanographic Institution).

10.5.2.2.2 Woods Hole Oceanographic Institution 2009 AUV Survey

WHOI conducted an AUV survey of the site with the Autonomous Benthic Explorer (ABE) Sentry

ROV system in July 2009. The Sentry AUV system incorporated a multibeam sonar system and 

camera for this survey. The Sentry survey collected approximately 21 images of the site, providing 

the first visual evidence that is was an historic shipwreck (Figure 10-37). These images were 
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compiled into the first digital site map of the wreck that was used to plan and undertake the 2009 

ROV investigation of the site.

Figure 10-37. Photomosaic of the 7,000 Foot Wreck comprised of images taken from the ABE 

Sentry AUV (Image Woods Hole Oceanographic Institution).

10.5.2.2.3 Lophelia II: Rigs, Reefs, and Wrecks 2009 Field Cruise

In September 2009, the first ROV investigation of the 7,000 Foot Wreck was conducted as part of 

the Lophelia II: Rigs, Reefs, and Wrecks Study. Over a roughly 15.5-hour period during 

September 6 and 7, 2009, the Lophelia II team used WHOI’s Jason II ROV launched from the 

NOAA Research Vessel Ronald H. Brown to document the shipwreck site.

The 2009 ROV exploration of the 7,000 Foot Wreck began with a standard reconnaissance survey 

around the wreck site. The project team began the reconnaissance at the bow of the wreck, moved 

aft down the starboard side around the stern and up the port side before ending again at the bow. 

During the 2.5 hour reconnaissance dive, the project team documented aspects of the wreck site 

including construction details, rigging remnants, machinery, and artifact assemblages, as well as 

biota found on the wreck site.

After completing the initial reconnaissance survey, the team set up to mosaic the wreck site with 

the ROV cameras. For the next 2 hours the ROV crew flew 12 lines over the wreck. Each line 

was run approximately 1 meter apart at an altitude of 6 m above the seafloor.

Once the mosaic survey was completed, the project team began investigation of the wreck’s 

biology. For the next 3 hour,s the team gathered biological samples (including rusticles) collected 

push cores, and deployed both long-term and short-term microbiological experiments.

With the biological and core sampling finished, the Lophelia II team spent the next 6 hours doing 

detailed documentation. During this phase of the dive, digital imagery and detailed still 

photographs were taken of key wreck features and artifacts noted during the reconnaissance 

survey. Once the documentation was completed, the recovery of potentially diagnostic artifacts 

from the site was undertaken. The recovery of the ship’s compass, a section of copper sheathing 

and the short-term microbiological experiment took up the last 2 hours of the investigation.
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10.5.2.3 Geographic Settings

The 7,000 foot wreck is located in the northern GoM in the eastern portion of the Mississippi 

Canyon area. It actually lies in 7,450-ft of water. At the time, the discovery represented the deepest 

historic shipwreck ever found in the GoM. The Mississippi Canyon is the outlet for sediment 

materials that transgress seaward into the Mississippi Fan. The Mississippi Fan is a submarine fan 

in the deepwater region of the GOM. Bouma and Coleman (1985) describe the canyon as a major 

erosional and partially filled structure. Initial development of this canyon is suggested to have 

begun around 50,000 to 55,000 years ago in the middle continental slope and retrogressed onto the 

shelf by 25,000 to 27,000 years before present. A pronounced eastward migration of the ancestral 

Mississippi River depocenter occurred depositing progradational sediments east of the present-day 

Mississippi River delta during the Middle Miocene period. The seafloor in this region gently 

slopes toward the south with local variations (Lee and George, 2002). 

10.5.2.4 Discussion of Archaeological Findings

10.5.2.4.1 Physical Site

The following description of the 7,000 Foot Wreck site (Figure 10-38) is compiled from data 

collected during the 2009 WHOI Sentry AUV survey and the 2009 Lophelia II ROV investigation.

The 7,000 Foot Wreck represents the remains a copper-sheathed wooden sailing vessel. The wreck 

is oriented with the bow pointing in a southerly direction and is lying upright on the bottom. The 

overall site size is approximately 27 m × 6.4 m. The hull remains of the 7,000 Foot Wreck are 

approximately 50 ft (15 m) × 15 ft (4.5 m) and is nearly flush with the seafloor, giving the vessel 

a 3:1 length-to-beam ratio

The 7,000 Foot Wreck site is composed of the main hull and associated remains (Figure 10-38 and 

Figure 10-39). The stem post and head knee, windlass, steering wheel and gear housing and three 

anchors are the most prominent features on the site. There are no identifiable debris trails or areas 

of isolated scattered debris associated with the wreck site. The wreck site is confined to a fairly 

well-defined area with only a section of foremast rigging observed extending outside the 

immediate vicinity.
389

Figure 10-38. Site map of the 7,000 FT Wreck based on ROV investigations.
390

Figure 10-39. Color photomosaic showing the 7,000 Foot Wreck site layout (Image Woods Hole 

Oceanographic Institution).

The head knee and stem post are relatively intact at the bow and are two of the most prominent 

features on the site. Along the vessel’s starboard side, various debris and artifacts were noted 

including wood and metal fragments, two bow anchors, and the vessel’s upside down windlass. 

Proceeding aft near amidships, other components were encountered including part of the ship’s 

water barrel, a galley stove, main mast remnants, decking, and another anchor. Further towards 

the stern, the ship’s compass was observed near a hatchway. To the rear of the hatchway, the 

remains of the ship’s patent steering stands proud of the seafloor and appears remarkably wellintact.

10.5.2.4.2 Bow and Hull

The 7,000 Foot Wreck has a sharp clipper-shaped bow and an elliptical stern or transom. The bow 

is similar to the bow found on the Lettie G. Howard, a two-masted schooner built at Essex, 

Massachusetts in 1893 (Figure 10-40). This type of vessel was commonly used by American 

offshore fishermen. The elliptical stern design was popularized during the 1840s and remained a 

quite prevalent construction characteristic in sailing vessels even into the 1920s.
391

Figure 10-40. American schooner Lettie G. Howard was built at Essex, Massachusetts in 1893 

(Image from South Street Seaport Museum, New York).

10.5.2.4.3 Stem and Head Knee

The remains of the bow include the remnants of the head knee (Figure 10-41). In older vessels 

this is often referred to as a beak. The head knee is attached to the stem post and served to the 

support the bow sprit. The stem post remains largely intact complete with two bobstay fittings and 

partially intact bobstay rigging. The stem post has a molded dimension of approximately 12 in

(30 cm) and a sided dimension of 8 in (20 cm). It extends approximately 6 ft (1.8 m) above the 

seafloor. The bobstay fittings are composed of iron and appear to be forged as single pieces. 

Bobstays were an integral part of the ship’s head rig and were important because they applied 

downward pressure to counteract the force affected on the bowsprit by the jib sails.
392

Figure 10-41. Stem post remains on the 7,000 Foot Wreck.

10.5.2.4.4 Windlass

An anchor windlass is a device that restrains and manipulates the anchor chain and/or rope,

allowing the anchor to be raised and lowered. Typically speaking, the term “windlass” refers only 

to horizontal winches. Vertical designs are referred to as capstans. Smaller vessels in general and 

merchant vessels in particular utilized horizontal winches or windlasses. The windlass consisted 

primarily of a barrel. Either hexagonal or octagonal in section, which included the bar holes, and 

which was supported at the end in the carrick bit. The pump-break type windlass was a further 

development of the concept. A column was mounted ahead of the windlass supporting a cross 

head into which bar could be inserted. The up and down pumping action of the cross head was 

converted into rotary movement by means of connecting rods and gearwheels positioned on the 

spindle. The ratchet-type action would engage the vertical links forward of the Samson post,

providing considerable leverage as the arms were pumped up and down to turn the windlass barrel. 

By the late 19th century many manually operated windlasses had been replaced by ones driven by 

small steam engines (Davis 1988; Mondfeld2005).

The windlass found on the 7,000 Foot Wreck was mounted crosswise on the foredeck of the vessel

(Figure 10-42, Figure 10-43 and Figure 10-44). It measures nearly 7 ft (2.1 m) in length. The 

warping drum, warping head and side bits remain relatively intact. One of the wooden side bit 

knees remains intact but the other has deteriorated. The windlass has flipped upside down from 

its original position. This may have occurred during the wrecking event or possibly over time as 

the wooden deck deteriorated. Remnants of deck planking can still be seen at the base of the knee. 
393

Figure 10-42. Image showing the over-turned windlass in bow of 7,000 Foot Wreck.

Figure 10-43. Overhead view of the over-turned windlass on 7,000 Foot

Wreck, bow is toward upper left corner of image.
394

Figure 10-44. Windlass on 7,000 Foot Wreck with individual components 

identified.

10.5.2.4.5 Rigging and Mast Components

A substantial amount of rigging remains present on the 7,000 Foot Wreck site. The observed 

rigging appears to be comprised entirely of wire rope. It is difficult to differentiate between

standing and running rigging on the site because of the orientation of the rigging as well as the

accumulation of sediments. The remaining wire rope may denote the heavier standing rigging and 

it is possible the more lightly constructed running rigging, if made out of hemp, sisal or similarly 

perishable natural fiber, has not survived over time. 

According to historical evidence, the development of a twisted (helical) rope formed from helical 

strands dates back to approximately 500 B.C. Examples of rope consisting of three strands twisted 

together; with each strand in turn, consisting of several bronze wires twisted together were 

unearthed during excavations at Pompeii (Worchester 1946).

There were relatively little technological advancements in the development of wire rope for the 

next 2,300 years. The invention of the steam plough in England around 1830 provided an increased 

demand for wire rope, but it was the Bessemer process that really provided a great technological 

leap forward. The Bessemer process was the first inexpensive process developed for the massproduction of steel from molten pig iron. Henry Bessemer patented the process in 1855. The 

process had a tremendous impact on both the quantity and quality of steel production (Bodsworth 

1998).
395

The invention of the first usable modern wire rope is credited to Wilhelm Albert, a German mining 

engineer between 1831 and 1834. The invention was not complicated and consisted of three 

lengths of all the same size wrought-iron wire twisted around each other by hand to make a strand. 

Next, three or four identical strands were twisted around one another in similar manner to make 

the rope. The wire rope was employed as hoisting cables in the vertical shafts of the Harz 

Mountain silver mines in Germany from 1834 to 1854 (Sayenga 1998).

While the Germans were achieving success using wire rope in the mining operations, Andrew 

Smith, a London inventor, was experimenting with various methods of applying wire ropes to 

ship’s rigging. Smith manufactured several kinds of wire rope for maritime applications, using 

the ropewalk techniques from the hemp cordage industry. Around the same time, another 

Englishman named Robert Newall devised a way to make wire ropes in a factory using machinery 

to replace the hand-twisted method (Sayenga 1998). 

Wire rope is composed of three parts: wires, strands and a core. The basic unit is the wire and a 

predetermined number of wires of the proper size are fabricated in a uniform geometric 

arrangement called the “pitch” of “lay” to form a strand (Figure 10-45). The completed strands 

are identical in diameter. The required number of strands are then laid together symmetrically 

around a core to form the rope.

All of the wire rope observed on the 7,000 Foot Wreck displays a “Regular Lay” or “Right Lay” 

(also known as a “Right-Hand Helix.”) or a “Lang Lay - Right Lay”) configuration. That is, the 

strands in the wire rope are laid to form a helix about the core similar to the threads of a typical 

screw. The strands, when viewed lengthwise, are wound helically away from the observer in a 

clockwise direction. However, from viewing video alone, it is nearly impossible to differentiate 

which of these two types of methods were employed as it is difficult to discern if the individual 

wires within the strands are laid in opposite directions.

Figure 10-45. Wire Rope Lays (Wire Rope and Fiber Rigging 

Navy Ships’ Technical Manuel Chapter 613).
396

10.5.2.4.6 Foremast Rigging

Several sections of rigging are visible at the wreck site (Figure 10-46 and Figure 10-47). One large 

section of rigging extends south away from the bow section. This rigging begins in the area near 

the over-turned windlass and extends out from the bow approximately 13.4 m. This rigging is 

likely from the foremast which would have been near the vicinity of the overturned windlass. The 

wooden mast deteriorated, leaving the rigging to mark its location.

Figure 10-46. Remnants of foremast rigging and mast cap from the 7,000 Foot Wreck.

Figure 10-47. Close-up view of foremast rigging and possible mast cap from the 7,000 Foot 

Wreck.
397

10.5.2.4.7 Mainmast Rigging

The rigging from the mainmast and foremast appear to be along the same alignment lying forward 

and 15 degrees to port. The mainmast fell in a forward direction and apparently ended up either 

directly on top of or alongside the foremast. This could have occurred during the initial wrecking 

event, but more than likely the masts remained partially held in place by the rigging following the 

sinking. These components would have been under stress and as the structural elements lost their 

integrity and began to deteriorate and fail, the mast would have toppled forward. Other than where 

the rigging originates and terminates, it is difficult to ascertain which rigging is associated with 

each mast (Figure 10-48). The location of the rigging depicted in Figure 10-49 probably denotes 

rigging associated with the main mast. A ring, approximately 6 in (15 cm) in diameter lies nearby 

and probably represents some type of rigging hardware. Several mast caps are visible on the site 

as well as the yoke for the gaff jaw that would have supported to boom on the mainmast. The 

purpose of the cap was to provide support for the topmasts. Mast caps were made of wood and 

iron in the 19th century. The rectangular hole in the rear was mounted over the mast head cap 

tenon while the topmast heel fit into the round hole.

Figure 10-48. Miscellaneous rigging in the bow of the 7,000 Foot Wreck.
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Figure 10-49. Mainmast rigging and components on the 7,000 Foot Wreck.

10.5.2.4.8 Mast Band and Yoke

A mast band and yoke lies amidships approximately 21.53 ft from the stern and 31.9 ft from the 

bow (Figure 10-50). The mast band measures 1.5 ft (0.46 m) inside diameter. The mast band or 

hoop attached to the fore edge of a boom sail, which slipped on the mast as the sail was raised or 

lowered. The spars, boom, gaff, job, bowsprit, etc. had standard ratios and proportions. Mast 

hoops were fitted around the masts to hold the component timbers, they were originally made of 

wood fixed in place with rope but by the end of the 19th century iron hoops had taken their place.

Figure 10-50. Mast band and yoke in the interior of the 7,000 Foot Wreck.
399

10.5.2.4.9 Sheathing

The 7000 Foot Wreck’s hull is constructed of wood that has been sheathed in copper or a copper 

alloy. A large section of sheathing was observed near the bow and appears largely intact. Twentytwo sheathing nails or tacks protrude up from the section (Figure 10-51 and Figure 10-52). The 

nails are approximately 1 inch (2.5 cm) long and are spaced approximately 3 in (7.6 cm) apart. 

The ROV attempted to recover what appeared loose sample of the sheathing, but this effort was 

abandoned when it became obvious the sheathing was still attached to the larger section. Another 

sheathing sample, however, was successfully recovered from another section of the wreck.

Figure 10-51. Copper sheathing with sheathing nails intact near bow of 7,000 Foot Wreck.
400

Figure 10-52. Close-up of a section of sheathing with sheathing nails intact in the 7,000 Foot 

Wreck.

10.5.2.4.10 Anchors

Three anchors have been identified on the 7,000 Foot Wreck. Two of these anchors are located 

on the bow (Figure 10-53 and Figure 10-54), the third is located amidships (Figure 10-55 and 

Figure 10-56). Their wooden stocks have long since deteriorated. The starboard anchor measures 

approximately 8 ft (2.4 m) in length, while to port anchor appears slightly smaller and measures 

about 6.5 ft (2 m) in length. The distance between the arms on the anchors measured 

approximately 2.67 and 2.40 ft (0.81 and 0.73 m), respectively. The slightly larger size of the

starboard anchor is not an unusual characteristic because sailing vessels often carried anchors of 

various sizes and weight. An anchor, as with any piece of equipment, was utilized as long as it 

remained in working order. As anchors were lost or damaged, they would be replaced with what 

was available. It is also possible that the use of different sized anchors at the bow was intentional 

to give the crew a choice of anchors to deploy, depending on conditions. The various 

measurements that were able to be ascertained from studying ROV video for each anchor are listed 

in Table 10-2.
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Figure 10-53. Anchor at starboard bow of 7,000 Foot Wreck.

As the 7,000 Foot Wreck deteriorated, the starboard anchor was deposited inside the hull and the 

port side anchor was deposited outside the hull. The flukes of both anchors are pointing towards 

the stern, suggesting they were still secured at their “ready” position on the bow at the time of the 

loss. 

Figure 10-54. Anchor at port bow of 7,000 Foot Wreck.
402

A third auxiliary anchor lies amidships. The iron from the anchor has defused into the surrounding 

wood and preserved a small section of decking it had once been contacting. The rest of the deck 

has collapsed and deteriorated, leaving the anchor leaning at an upright angle on the bottom. The 

third anchor would have been more than likely been used as a spare anchor in the event the vessel 

lost one of its primary anchors or could have been deployed during an emergency. It was 

impossible to accurately determine the anchor’s size from the overall data, due to its orientation 

and angle in which it is sitting (Figure 10-57).

Figure 10-55. Auxiliary anchor amidships on the 7,000 Foot Wreck (view to starboard).
403

Figure 10-56. Auxiliary anchor amidships on the 7,000 Foot Wreck (view to starboard).

Figure 10-57. Image showing standard measurement points for anchor documentation.
404

Table 10-2.

7,000 Foot Wreck Anchor Data Information

Measurement 

Point

(Fig 10-57)

Standard Measurement Point Description Bow (Port) Bow 

(Starboard)

Third 

Anchor

A Ring diameter .51’ N/A .83’

B Ring thickness N/A N/A .125’

C Top of shank to base ring N/A N/A .135’

D Top shank diameter .19’ .25’ .25’

E Distance from top stock to top of shank N/A N/A

F Stock width on each end – right N/A N/A

F Stock width on each end – left N/A N/A

G Stock thickness next to shaft N/A N/A

H Stock width each end of shank – right N/A N/A

H Stock width each end of shank – left N/A N/A

I Stock length N/A N/A

J Stock thickness at ends – right N/A N/A

J Stock thickness at ends – left N/A N/A

K Length of shaft 6.54’ 8.00’ 5.83’

L Mid-shank diameter .18’ .26’ .30’

M Basal shank diameter .20’ .33’ .33’

N Arm diameter – right .34’ .40’ .36’

N Arm diameter – left .33’ .39’ .36’

O Thickness of arm N/A N/A

P Width of palms – right N/A N/A

P Width of palms – left N/A N/A

Q Length of palms – right N/A N/A

Q Length of palms - left N/A N/A

R Distance between arm tips 2.40’ 2.67’ 2.50’

S Palm thickness – right N/A N/A .160’

S Palm thickness – left N/A N/A .160’

T Arm thickness at end of palm – right N/A N/A .167’

T Arm thickness at end of palm – left N/A N/A .167’

U Distance from end of palm to arm – right N/A N/A

U Distance from end of palm to arm – left N/A N/A

10.5.2.4.11 Wheel and Steering Machinery 

One of the most impressive components of the 7,000 Foot Wreck is the ship’s wheel and steering 

machinery (Figure 10-58). The amazingly intact feature is located at the stern of the vessel. The 

wheel appears to be iron. The wooden handles have mostly deteriorated, except for a partial 

remnant of one handle. At least one quarter of late 19th century sailing vessels were fitted with 

steering mechanisms that included patented double worm steering gears (Gordon P. Watts. Jr., 

personal communication), however, in the case of the 7,000-Foot Wreck, it is nearly impossible to 

match this machinery with a patented model from just a visual inspection. Even if the steering 

machinery found on the 7,000-Foot Wreck featured a patented worm steering gear, it would be 

difficult to determine whether it was fitted with this equipment initially, or it was adapted at a later 

point in the vessel’s career.
405

Figure 10-58. The 7,000 Foot Wreck’s helm, showing the wheel, exposed wheel-box, and 

rudder case.

The steering gear housing encountered on the 7,000 Foot Wreck is much more reminiscent of 

American-built vessels of the late 19th century. Figure 10-59 and Figure 10-60 depict the 

differences between typical European steering gear housings and American steering gear housings

from the same time period. The steering gear housing is also known as a wheel-box. The gear 

housing box measures approximately 4 ft (1.2 m) long × 2.8 ft (0.85 m) wide × 2 ft (0.60 m) high

based upon all the available data. The wheel itself measures approximately 2.65 ft (0.80 m) in 

diameter (Figure 10-61). The entire structure stands about 4 ft (1.21 m) off the bottom. Based on 

Chapelle (1973), the design and angle at which the wheel shaft on the 7,000 Foot Wreck goes into 

the box suggests it is a style of wheel-box that was very common on vessels built between 1860 

and 1885. 
406

Figure 10-59. Steering gear housing European type, 

late 19th century (Mondfeld).

Figure 10-60. Steering gear housing American type, 

late 19th century (Mondfeld).

Figure 10-61. Ship's wheel similar to that on 

the 7,000 Foot Wreck (Drawing by 

Daniel Warren, Image modified from 

Chapelle, Fishing Schooners).
407

10.5.2.5 Artifacts

10.5.2.5.1 Stove

An object tentatively identified as the ship’s stove was observed on the starboard side amidships 

approximately 27.50 ft aft of the stem post (Figure 10-62). The stove measures approximately 

4.54 (1.4 m) × 1.86 (0.57 m) ft. The ship’s stove aboard late 19th and early 20th century vessels 

was an important feature. It provided dual functionality, as it provided a both a heat source for 

cooking and warmth to the crew during times of cold weather.

Figure 10-62. Image from the 7,000 Foot Wreck showing a possible galley stove (center) and a 

possible water barrels (center left and bottom left).

10.5.2.5.2 Water Barrel

The deteriorated remains of what may represent a wooden water barrel was noted just aft of the 

stove (Figure 10-62). Two edges of the barrel are protruding upright from one end, while the 

opposite edges have collapsed inward. The fact that various items identified as a stove, lantern 

and possible water barrel lie in close approximation to one another suggest this area may have 

contained the ship’s galley.
408

10.5.2.5.3 Bottles and Containers

At least one possibly intact bottle was observed near the bow section. One intact jug, possibly a

demijohn was also visible (Figure 10-63). Other bottle fragments were observed clustered in the 

same area but the exact number could not be ascertained since most of the fragments were partially 

buried or obscured by silt and debris. The bottle is manufactured of dark, possibly green, glass. 

The jug appears to possibly be brown slipped stoneware, but it is difficult to determine based on 

the video data. The presence and number of the containers indicate they are associated with daily 

shipboard activities rather than cargo. Their location in association with other artifacts, such as 

the nearby stove suggests this portion of the wreck contained a crew area, most likely the galley. 

Figure 10-63. A bottle (A) and Jug (B) in the forward area of the 7,000 Foot Wreck.

10.5.2.5.4 Hanging Knee:

A hanging knee possibly from the deck above has fallen onto the stove (Figure 10-64). The knee 

measures approximately 3.92 (1.19 m) × 1.90 (0.58 m) ft. This tentative identification is based on 

the size and shape of the object. Hanging knees were a vertical angular timber shaped into a right 

angle. They were used to reinforce and support the ends of the deck beams where they came into 

contact with the sides of a vessel (Steffy 1994). 
409

10.5.2.5.5 Lantern

The deteriorated remains of what appears to be a lantern are located on the stove (Figure 10-64). 

The round base measures approximately 6 in (15 cm) in diameter and is made of a grayish, 

apparently non-corrosive metal. Part of the frame and two possibly brass adjustment screws were 

observed protruding from the sediment. Since no glass was observed, it is either missing or 

dislodged and buried. 

Figure 10-64. Image of a lantern resting on top of the ship's stove in the forward area of the 

7,000 Foot Wreck.

10.5.2.6 Recovered Artifacts

Three artifacts, the ship’s compass, a sample of metal sheathing, and a wood sample were 

recovered from the 7,000 Foot Wreck site during the 2009 investigation. The artifacts were 

conserved at the UWF Archaeology Institute’s conservation lab in Pensacola, Florida and the 

conservation report can be found in Appendix E-2. 

One of the most potentially diagnostic artifacts selected for recovery was a ship’s compass

(Artifact MMS09.15373.CO.001.) Jason II successfully retrieved the compass at 9:12 on 

September 7, 2009 (Figure 10-65). The compass was located in an area just forward of the wheel 

box, which is consistent with historical data for ships of the period. Originally, compasses such as 
410

this would have been mounted in a box, on a pedestal, or housed in a binnacle in the vessel’s bridge 

or steering cockpit.

Figure 10-65. The 7,000 Foot Wreck's compass being recovered during the 2009 site 

investigation.

The compass is circular, with an outer ring attached at two opposite points, a glass cover on the 

face, and a hollow center filled with liquid and the compass card. The outer circle of the compass 

rotates around the main body of the compass itself, and has two prongs that stick out from opposite 

sides. The compass is marked "D.Baker & Company – Boston" (Figure 10-66). The floating wet 

compass card has a patent date "PAT'D NOV 3, 1874-JUNE 1, 1875. The card is divided into 

eight Cardinal Points, each of 45 degrees, and then into 1/8 and 1/16th points. Each subtends an 

arc of 111⁄4 degrees comprising in total 360 degrees of the compass. 
411

Figure 10-66. The 7,000 Foot Wreck's compass following 

conservation.

According to historical research and interviews with a descendant, David Baker was born on 

November 7, 1817 in Harwich, Massachusetts on Cape Cod and was a seaman and then a ship’s 

captain for many years until he retired from that and started his company making compasses. He 

moved off the Cape to Boston. The 1860 census has his residence still in Harwich. The 1860, 

1870, and 1880 census has his residence in Boston. The 1890 census has his residence in Melrose, 

Massachusetts. David died August 26, 1895 and his sons George and Howard Bakertook over the 

company and ran it for some unknown amount of years. According to Paul Baker, the company 

may have been bought out by Star Compass around 1915, but he has been unable to locate any 

historical documents to confirm that information (Personal correspondence, 2012 and 2013). 

David Baker held many U.S.patents in his compass design, one of which was the use of oil instead 

of the standard alcohol and water mix in use at that time. His patent for using oil was actually very 

revolutionary and that type of oil is still used in modern compasses today. Some of David Baker’s 

patents are shown in Table 10-3.
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Table 10-3.

Patents awarded to David Baker

U.S. Patent # Description Date

 7,837 Design for Compass Card November 3, 1874

163,838 Improvement in Mariner’s Compass June 1, 1875

568,227 Mariner’s Compass September 22, 1896

The compass recovered from the 7,000 Foot Wreck has a serial #3883 stamped on both the 

compass and gimbal ring (Figure 10-67). The compass comes from a period when makers were 

experimenting with different innovations for flotation compasses. The Baker compass was a 

popular instrument from its first appearance on ships in the 1870's and 1880’s.

According to Howard Maglathlin of Viking Instruments, Inc. located in Kingston, Massachusetts,

the Baker Company was actually located in Melrose, Massachusetts, just north of Boston. Later 

David Baker worked with a partner, Thomas Hooper at 54 Ann Street in Boston. It appears the 

earlier examples were marked "BOSTON" while the ones bearing the later 5-digit serial numbers 

were marked MELROSE MASS. This indicates that the compass found on the 7,000-Foot Wreck 

is an earlier production model Baker compass (Maglathlin, personal communication). 

Figure 10-67. Serial numbers located on the outer edge of the 7,000 Foot Wreck's compass.
413

The compass provides a “terminus post quem” of 1875 for the 7,000 Foot Wreck, but is not an 

indicator of a loss date. According to marine archaeologist Gordon Watts, “a compass that works 

is a working compass” and as such it would have been a prized possession of mariners from any 

era and utilized as long as it was in good working order (Watts, personal communication). So it 

is not inconceivable that the compass could be much older than the vessel represented by the 7,000 

Foot Wreck.

The sample of metal sheathing (Artifact: MMS09.15373.M.002) consists of three small sections 

of sheathing attached to wood with tacks (Figure 10-68). The wood is flat on the external side, yet 

the opposite side is riddled with damage from marine organisms. Many Teredo navalis tubes were 

pulled from the artifacts before conservation. The wood is colored green and black, presumably 

stains from the oxidation that occurred to the cuprous sheathing during its time underwater. The 

wood is soft and spongy, and flakes at the slightest touch. A series of cuprous metal tacks line the 

corners of the sheathing. 

Figure 10-68. Cuprous metal sheathing and wood recovered from the 7,000 Foot Wreck.
414

Table 10-4.

Dimensions of Copper Sheathing from the 7,000 Foot Wreck

Piece 1 Piece 2 Piece 3

Length 29cm 22cm 18.5cm

Width 18cm 9.5cm 7cm

Thickness 3cm 3cm 3cm

Weight 203.5g 182.6g 112.7g

Subsequent conservation revealed the wood itself was a light brown under the metal, indicating 

that it had been well protected by the sheathing; while the rest of its exposed surface was a dark 

brownish green color. Dr. Amy Mitchell-Cook, an underwater archaeologist and history professor 

at UWF who specializes in wood identification examined the sample and determined that the 

wooden planks beneath the sheathing were either white or red oak, due to the strong, single rays 

running out from the center/ heart of the wood.

This artifact was originally intended as a wood sample thought to contain copper sheathing at the 

time of recovery (Figure 10-69). Subsequent conservation revealed the sample contained no 

sheathing. The object consisted of eight small fragments of wood and calcareous marine growth. 

Figure 10-69. Wood Sample from 7,000 Foot Wreck.
415

10.5.2.7 Site Preservation

The wreck site is currently in a moderate state of preservation. The hull is partially intact where 

it is sheathed. The sheathing’s anti-biofouling properties likely offer some protection to the hull 

sections in direct contact with it. This is consistent with other GoM deep-water discoveries, where 

wooden hull remains are present in conjunction with copper sheathing and largely absent above 

the line of sheathing. The stem post and head knee remains partially intact. The ship’s wheel and 

steering gear housing are also remarkably intact. Since the wreck is mostly buried, an accurate 

assessment of its preservation state cannot be made, but it is likely that it has been protected by 

the seafloor sediments and remains relatively intact. 

In an effort to monitor the wreck’s preservation and rate of deterioration, a short-term etching 

microbial tester and long-term WW-GUCCI platform were deployed at the 7,000 Foot Wreck site 

to study microbial activity and monitor deterioration rates. The etching tester was not left in place 

long enough for a reaction to occur and provide information on the level of microbial activity at 

the site. The WW-GUCCI platform, deployed near the ship’s steering gear housing, is designed 

to provide a long-term indication of site deterioration rates from microbial and chemical 

deterioration. Reexamination of the test platform in the future will be invaluable in assessing longterm preservation of the 7,000 Foot Wreck site.

10.5.3 Ewing Bank Wreck Site

10.5.3.1 Historical Background of the Ewing Bank Wreck

The Ewing Bank Wreck is the remains of a wooden sailing vessel that may date from the latter half 

of the 19th century. Discovered in 2006 during an oil and gas exploration survey, the wreck was 

named for the lease block area where it was found. Archival research undertaken since 2006 has 

failed to identify the name or nationality to this shipwreck. Since its discovery in 2006 there have 

been two AUV and two ROV investigations of this site.

10.5.3.2 Field Investigations

10.5.3.2.1 Discovery and Exploration

In 2006, Remington Oil and Gas Corporation wasconducting explorations of the deep waters of 

the Ewing Bank region in the GoM for potential oil and gas development. Remington contacted 

C&C Technologies, Inc. (C&C) to conduct a geophysical survey of the area using C&C's CSurveyor II AUV system. Since the Ewing Bank Lease Area had recently been designated an 

archaeological high-probability zone, the survey included an archaeological assessment.

During the assessment of the geophysical survey data, a C&C marine geologist identified a target 

that looked ship-like in shape (Figure 10-70). Side scan sonar data showed an ovoid area of 

moderate reflectivity enclosing an area of high reflectivity. Measurements taken from the sonar 

and multibeam data indicated the target was approximately 45 m long, 12 m wide, with 2.5 m of 

relief.
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The target was brought to the attention of C&C marine archaeologists who confirmed it was a 

likely shipwreck site. A check of available shipwreck databases found that no wreck had been 

previously noted in the area. Since this was a new discovery, the then MMS Social Sciences Unit 

was notified as stipulated under Notice-to-Lessees (NTL) 2005-G07. The MMS concurred that it 

was likely a shipwreck site and established a 1,000-foot radius avoidance zone around the wreck 

area.

In November 2006, a following survey for ATP Oil and Gas, Inc. (which had recently purchased 

Remingtion Oil and Gas) was conducted on several anchor placement locations in the Ewing Bank 

area. As part of this survey, a series of lines were also flown over the Ewing Bank Wreck site 

using the C-Surveyor AUV at an altitude of approximately 20 m. Data from the AUV's 430 kHz 

side scan sonar, subbottom profiler, and multibeam systems confirmed it was a shipwreck. 

Based on the details from the side-scan sonar, the wreck appeared to be the remnants of a wooden 

sailing vessel. The intact nature of the wreck indicated that it could be copper sheathed. A linear 

feature, running down the center of the wreck was speculated to be keelson remains. An area of 

disturbed seafloor to the port side was thought to be ballast. The side-scan data did not show any 

debris trails outlying from the wreck. Subbottom data indicated the hull was partially buried in 

the seafloor. Despite the high-frequency data, the determination of bow and stern could not be 

made, nor could a determination of age.
417

Figure 10-70. A 2006 210p- kHz side scan sonar image of the Ewing 

Bank Wreck (ATP Oil and Gas).

10.5.3.2.2 C&C Technologies, Inc. 2007 AUV Survey

In 2007, C&C's C-Surveyor II AUV underwent sea trials and testing following a system upgrade. 

One of the test locations was the Ewing Bank Wreck. During a single dive, several test lines were 

flown over the wreck at an altitude of approximately 20 m to image it with the AUV's 430 kHz 

side-scan sonar, subbottom profiler, and multibeam systems (Figure 10-71). Review of the data 

reconfirmed the findings of the 2006 surveys. Despite the additional data, scientists were still 

unable to discern the bow and stern or determine an accurate age for the vessel.
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Figure 10-71. A 410-kHz side scan sonar image of the Ewing Bank Wreck (C & C 

Technologies, Inc.)

10.5.3.2.3 Lophelia II: Rigs, Reefs, and Wrecks 2008 Field Cruise

In September 2008, the first ROV investigation of the Ewing Bank Shipwreck was conducted as 

part of the Lophelia II: Rigs, Reefs, and Wrecks Study. Over September 6 and 7, 2008, the 

Lophelia II team used a SeaEye Falcon ROV launched from the NOAA Research Vessel Nancy 

Foster to explore the shipwreck site.

Despite ROV and equipment issues, the team explored the wreck site for just under 8 hours over 

the two-day period. During this time the ROV completed a reconnaissance survey of the wreck 

collecting both video and still imagery. Archaeologists confirmed the wreck was historic and 

completed a preliminary map of the wreck site, determining that the bow was at the northern end 

of the wreck, and that what was originally thought to be ballast on the port side was actually a 

sediment berm. During the investigation, biologists also documented coral colonies and took core 

samples from around the wreck for later analysis. 

10.5.3.2.4 2009 C&C Technologies, Inc. AUV Survey

In June 2009, C&C conducted a second AUV survey over the Ewing Bank Wreck. This survey 

was part of an internal testing program for C&C's new AUV underwater photographic system on 
419

the C-Surveyor III AUV. Launched from the support vessel M/V Miss Ginger, C-Surveyor III ran 

five camera transects over the wreck at 5-meter intervals between lines. The AUV's camera system 

collected 64 images of the wreck site and surrounding area. A photomosaic compiled of these 

images by C&C gave scientists there first complete site photograph of the Ewing Bank Wreck. 

This photographic mosaic assisted scientists in planning and conducting the September 2009 ROV 

investigation of the site. 

10.5.3.2.5 Lophelia II: Rigs, Reefs, and Wrecks 2009 Field Cruise

In September 2009, the second ROV investigation of the Ewing Bank Shipwreck was conducted 

as part of the Lophelia II: Rigs, Reefs, and Wrecks Study. Over a roughly 12-hour period during 

September 7 and 8, 2009, the Lophelia II team used Woods Hole Oceanographic Institution’s

Jason II ROV launched from the NOAA Research Vessel Ronald H. Brown to document the 

shipwreck site.

The 2009 ROV exploration of the Ewing Bank Wreck began with a standard reconnaissance survey 

around the wreck site. The wreck reconnaissance started at the stern, moved up the starboard side, 

around the bow, and down the port side before ending again at the stern. During the roughly 2-

hour reconnaissance dive, the project team documented aspects of the shipwreck including 

sheathing, fastener, and framing details, as well as sessile, invertebrate, and vertebrate fauna found 

on the wreck (Figure 10-72).

For approximately the next 1 1⁄2 hours following the reconnaissance survey, a series of mosaic lines 

were run over the wreck. Since a detailed mosaic of the Ewing Bank wreck was made previously 

using high-resolution AUV camera images, only 6 mosaic lines were flown with the Jason II ROV 

system. During the mosaic survey, Jason II flew 1 meter transects at an altitude between 5.5 and 

6.5 m above the seafloor. 

Once the mosaic survey was finished, the next 2 1⁄2 hours were spent collecting biological samples 

and deploying both long-term and short-term microbiological experiments. During this time span,

9 push cores were collected and a long-term microbiological test platform was placed forward of 

the stern along the wreck's centerline.

After completing the biological and core sampling, the project team conducted detailed inspection 

of areas of the wreck noted during the reconnaissance survey. Investigating and capturing still 

imagery of key features of the wreck, along with the recovery of 4 diagnostic artifacts took 

approximately 4 1⁄2 hours to complete. Once the detailed inspections were finished, the next hour 

was spent gathering rusticle samples and retrieving the short-term biological experiments before 

terminating the investigation and returning the ROV to the surface
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Figure 10-72. The 2008 field drawing of the Ewing Bank Wreck 

(Anne Corscadden Knox and PAST Foundation).
421

10.5.3.2.6 2012 C&C Technologies, Inc. AUV Survey

In September 2012, C&C conducted a third AUV survey over the Ewing Bank Wreck. This survey 

was part of an internal testing program related to C&C's AUV underwater photographic system on 

the C-Surveyor III AUV. Launched from the support vessel M/V Miss Ginger, C-Surveyor III ran 

40 camera transects over the wreck and a large area around it at 4-meter intervals between lines. 

During this survey, over 6,700 images of the wreck site and surrounding seafloor were obtained.

10.5.3.3 Geographical Setting 

The Ewing Bank shipwreck site is located on the upper Louisiana continental slope in a water 

depth of 2,040 ft Mean Sea Level (MSL). The shelf break is oriented northeast to southwest 15 

miles to the north-northwest of the site, and the Mississippi Canyon is found 35 miles to the 

northeast. A broad, low-relief submarine ridge of overbank deposits occurs between the shipwreck 

site and Mississippi Canyon (R. George, personal communication 3/16/2012).

The shipwreck is located on the eastern flank of a bathymetric trough oriented north-northwest to

south-southeast. The seabed slopes southwest at 2.3 degrees. The bathymetric trough is 4,000 ft

across with 50 ft of relief. It feeds into a basin extending across the southern half of portions of the 

Ewing Bank area (R. George, personal communication 3/16/2012).

Recent sedimentation in the area is primarily hemipelagic clay which has a very soft consistency. 

Turbidity flows originating upslope from the site are presumed to occur periodically and are a 

source of silt and clay. Landslide or debris flow units which formed during the last marine 

transgression underlie the site. The seabed irregularities found across the area are the topographic 

expression of these underlying debris flows (R. George, personal communication 3/16/2012).

The Ewing Bank wreck is resting on a south-trending slope. The average seafloor gradient at the 

wreck site is 1 degree (Figure 10-73). Seafloor sediments around the wreck are characterized as 

soft silty clays or mud (Warren, 2006).
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Figure 10-73. Multibeam bathymetry image of the Ewing Bank Wreck (C & C Technologies, 

Inc.).

10.5.3.4 Discussion of Archaeological Findings

10.5.3.4.1 Physical Site

The following description of the Ewing Bank Wreck site is compiled from data collected during 

the 2009 and 2012 C&C AUV camera surveys and the 2008 and 2009 Lophelia II ROV 

investigations.

The Ewing Bank Wreck represents the remains of a sheathed wooden sailing vessel. The wreck is 

oriented with the bow facing a north-northeasterly direction (Figure 10-74). Average water depth 

at the site is 621 m BSL. There are no discernible debris scatters outside the immediate area of 

the wreck. The overall site size is roughly 40 m × 13 m.

The Ewing Bank Wreck site is composed of only the main hull and associated remains. There are 

no observed debris trails or areas of isolated scattered debris associated with the wreck site. The 

wreck is resting upright on its keel but appears to have a port list (west). The wreck site is confined 
423

to a small area and consists of three distinct components: the main hull remains (Figure 10-75, 

Area 1); the exterior port debris zone (Figure 10-75, Area 2); and exterior stern debris area, 

inclusive of associated materials along the port and starboard stern quarters (Figure 10-75 Area 3).

Figure 10-74. Site map of the Ewing Bank Wreck based on ROV investigations.
424

Figure 10-75. Photomosaic of the Ewing Bank Wreck showing the three main areas of the wreck 

site: Area 1 (red outline) is the main hull; Area 2 (black outline) is the port debris 

zone; and Area 3 (blue outline) is the stern debris area (Image C &C Technologies, 

Inc.)
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The dominant feature at the site is the Ewing Bank Wreck’s hull (Figure 10-75, Area 1). The hull 

is extant from just below the water line to the keel and is sheathed in a cuprous metal (Figure 

10-76). Portions of both the stempost and sternpost remain intact. It is oriented with the bow to 

the north-northeast. The wreck sits on the seafloor with a 7 to 10 degree port list based on the 

angle of the hull. The hull remains of the Ewing Bank Wreck are approximately 120 ft (36.5 m) × 

33 ft (10 m) with 10 ft (3 m) of the hull extending above the seafloor, giving the vessel a 4:1 lengthto-beam ratio. The hull is moderately sharp at the bow, with rounded turn-of-the-bilge, and broad 

beam.

Because of the port list, a portion of the starboard hull is exposed (Figure 10-77). The sheathed 

portion of the stem post is intact and still attached at the bow. Aft of the stem, silt covers much of 

the forward hull’s interior. Along the port and starboard interior hull edges, cant frames protrude 

from the silt. Ceiling planking remnants overlay portions of the port frames. Throughout this area, 

vestiges of possible decking remnants are scattered about. 

Within the waist, the vessel’s stone ballast is obscured by a thin veil of silt (Figure 10-78). The 

ballast covers the width of the lower hull and extends from just aft of the forecastle region of the 

bow to just forward of where the stern tuck begins. Fragments of piping and possible structural 

components are strewn over the top of the ballast. On either side of the ballast, the deteriorated 

tops of frames or futtocks are visible just above the silt line as they extend up the side of the hull 

from beneath the ballast.

Aft of the ballast pile, in the stern area, a possible keelson remnant and a stern frame are visible. 

To the starboard of the possible keelson remnant, caulking remnants that lie up the side of the hull 

serve to outline the location of long-deteriorated ceiling planking. To the port and slightly aft of 

the potential keelson piece is a concentration of ceramics. Within the hull, sediments cover much 

of this material, but numerous fragments of vessels are exposed near the edge of the hull. 

Intermixed with the ceramics are two sections of metal pipe, possibly lead, connected by a metal 

flange. Continuing aft from keelson area, the stern post is partially intact and still attached to the 

hull. The stern post is also sheathed in copper or copper alloy. The rudder is missing, but a single 

gudgeon strap is still intact with a partial pintle attached to it.
426

Figure 10-76. View of bow and stempost of Ewing Bank Wreck (Aquapix 

Camera Image, Lophelia II, 2009: Deepwater Coral Expedition: 

Rigs, Reefs, and Wrecks).

Figure 10-77. ROV video image capture of exposed hull remains at the Ewing 

Bank Wreck’s starboard bow.
427

Figure 10-78. AUV Camera photograph showing a portion of the Ewing Bank

Wreck's ballast pile. (C & C Technologies, Inc.)

On the port (western) exterior of the hull, a low-relief sediment berm has built up, obscuring much 

of the exterior port hull (Figure 10-79). The berm appears to have built up over time around 

remnants of the upper hull that collapsed onto the seafloor. The apparent stratified remains within 

this berm make up the “port debris zone” (Area 2 on overall mosaic). At its greatest width, this 

debris zone is approximately 3 m wide. Although much of the deposits are buried within the silt, 

a myriad of partially decayed wooden hull components, copper fasteners, and unknown 

conglomerates are exposed on the berm’s surface. The density of materials is highest along the 

midship area, but diminishes rapidly at the bow and stern.

The edge of the exterior stern debris zone is just aft of where the hull turns toward the stern post 

on the port side (Figure 10-80 and Figure 10-81). This debris area is demarcated by an irregular 

sediment stain, seen in the AUV imagery, encompassing the stern area. This stain, which may 

represent the only remnants of the upper stern overhang, extends approximately 6 m across the 

stern and 2.4 m aft of the stern post. Within this debris area are hull remnants, including the 

possible remnants of the rudder, corroded and unidentifiable iron conglomerates, and intrusive 

material, which include a modern fishing net. This debris area ends abruptly on either side of the 

hull at the point where the hull turns toward the bow.

Moving up the starboard side of the hull, there is very little debris on the seafloor. Because of the 

port list, the starboard hull is exposed. In some areas the side of the hull is exposed from the turnof-the-bilge to the edge of the remaining sheathing, a distance of up to 76 cm. Along this side of 
428

the vessel, there is a noticeable absence of material remains equivalent to those on the port side. 

The seabed here is free of materials, other than intermittent sections of sheathing that have fallen 

off the hull.

Figure 10-79. AUV camera photograph showing portions of the exterior 

port debris zone and the Ewing Bank Wreck's interior hull (C & C 

Technologies, Inc.).

Figure 10-80. AUV camera photograph of the stern and stern debris 

area of the Ewing Bank Wreck (C & C Technologies, Inc.).
429

Figure 10-81. ROV video capture image looking north towards stern and stern debris 

area of the Ewing Bank Wreck

10.5.3.4.2 Bow

The bow area of the hull is identified by the partially intact stempost (Figure 10-82). The stempost 

is wood and has a large colony of Lophelia pertusa coral growing on its upper sections. The stem 

is the highest point of relief on the wreck sites. It extends approximately 12 ft (3.6 m) above the 

seafloor and has sided and molded dimensions of 6 in (15 cm) and 12 in (30 cm), respectively. 

The stem assembly appears to show the stempost, apron, and possible breast hook. The stem 

deadwood and lower stempost are not visible. The stem flares out slightly from the hull near the 

keel. This flare increases near the top of the stem.

The outer portion of the stem is sheathed with copper or copper alloy (Figure 10-83). The 

sheathing on the stem extends 2 ft (0.61 cm) higher than the top of the existing copper on the hull. 

This suggests the waterline was higher than represented by the remaining hull sheathing. There is 

also a significant amount of iron and corrosion product on the stem. Using the current data, it is 

difficult to ascertain whether this is a result of iron plate that has been added to the stem as a repair 

or re-enforcement, or corrosion from numerous iron fasteners.
430

Figure 10-82. ROV video capture image of the Ewing Bank Wreck’s stempost 

(port view) with major components identified.

Figure 10-83. Photograph of copper sheathing on the Ewing Bank Wreck’s 

stempost (Aquapix Camera Image, Lophelia II, 2009: Deepwater 

Coral Expedition: Rigs, Reefs, and Wrecks).
431

10.5.3.4.3 Frames and Outer Planking

Sediment and ballast obscure much of the Ewing Bank Wreck’s construction details. The 

assessment of framing and outer planking details is based on examination of exposed or partially 

exposed timbers near the hull edges. 

Overall, the Ewing Bank Wreck is a stoutly built vessel. Cant frames are visible in the bow (Figure 

10-84). Several of these are partially exposed on the starboard bow just below the edge of the 

extant sheathing. The cant frames in the bow are approximately 12 in (30 cm) sided (molded 

dimension measurements could not be taken) and set at an approximate angle of 20° to the assumed 

centerline keel location. 

In several areas along the interior edge of the hull, portions of main timbers are exposed. Only a 

few of these are intact enough to show edges. Based on the limited scope of the video data, the 

Ewing Bank Wreck appears to have paired frames, with a room and space averaging 14 in (35.6 

cm). The deteriorated condition of many of the frames and the build-up of silt hampers detailed 

measurements of the frame timbers.

Near the port bow, a section of the interior hull between the outer planking or strakes and the 

interior ceiling planking is intact (Figure 10-85). The space between the strakes and the ceiling 

planking is approximately 4 in (10 cm). From this information, it can be surmised that frames in 

this section of the hull could have had a molded dimension of up to 4 in (10 cm). This image also 

indicates that the outer planking was approximately 3 in (7.6 cm) thick.
432

Figure 10-84. AUV camera photograph of the Ewing Bank Wreck’s bow interior 

showing cant frames (C & C Technologies, Inc.).

Figure 10-85. ROV video capture image showing the Ewing Bank Wreck's outer 

hull planking, hull framing, and interior ceiling planking.
433

10.5.3.4.4 Ceiling Planking

In several locations on the wreck, vestiges of the Ewing Bank vessel’s interior ceiling planking is 

visible. In some cases, planks are partially intact, while in other places, only the caulking remains 

to outline the shape of the now-disintegrated ceiling planks. Figure 10-86 shows one of the few 

partially intact ceiling planks on the wreck. Near the beginning of the starboard stern tuck, a 

section of ceiling planking is visible at the edge of the hull. This piece of planking is approximately 

3 in (7.6 cm) thick.Near the same area, but further down in the hull’s interior, Figure 10-87 shows 

an area where the ceiling planking has deteriorated, but the caulking remnants outline individual 

planks. Measurements of the caulking indicate the ceiling planking was approximately 4 in (10 

cm) wide.

Figure 10-86. ROV video capture image showing ceiling planking on the Ewing 

Bank Wreck’s starboard stern.
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Figure 10-87. ROV video capture image of caulking remnants outlining 

disintegrated ceiling planking in the Ewing Bank Wreck’s starboard 

stern.

10.5.3.4.5 Stern

The stern post is still partially intact and attached the hull (Figure 10-88). The remaining section 

is nearly vertical, measuring approximately 4 ft (1.2 m) high, 12 in (30 cm) sided, and 12 in (30 

cm) molded. A section of sheathing that once protected the missing upper section of stern post is 

folded over onto the seafloor. This piece, approximately 3 ft (0.91 m), indicates that the stern post 

was sheathed to at least a height of roughly 7 ft (2.1 m).

Attached to the sternpost are a gudgeon and a portion of a pintle. The sternpost gudgeon measures

12 in (30 cm) in length, 12 in (30 cm) in width, and 2.5 in (6.4 cm) deep. It has a circular opening

on its after edge to allow the pintle’s vertical pin to attach to the gudgeon. Both the gudgeon and 

the pintle appear to be manufactured as single pieces. The pintle is broken near the edge nearest 

the gudgeon. It is a clean break and there does not appear to be any evidence of twisting that would 

indicate a forced break. The pintle, like the gudgeon, is 12 in (30 cm) wide, 2.5 in (6.4 cm) deep, 

and, although broken, its length is likely 12 in (30 cm), the same as the gudgeon. The pintle and 

gudgeon appear to set flush, indicating the vertical pin fitting into the gudgeon is, at most, 2.5 in

(6.4 cm) long. The diameter of the pintle’s vertical pin could not be assessed from the current data. 

No other gudgeon braces or traces of the rudder have been positively identified, although debris 

that could be related to the rudder mechanism is present near the starboard side of the sternpost.
435

Figure 10-88. Photograph showing details of the Ewing Bank Wreck’s stern (Aquapix 

Camera Image, Lophelia II, 2009: Deepwater Coral Expedition: Rigs, Reefs, 

and Wrecks).

10.5.3.4.6 Fasteners

Several varieties of fasteners are present at the Ewing Bank Wreck. These fasteners range from 

small sheathing nails to large spikes and bolts, called drift pens. All of the fasteners appear to be 

hardened copper or copper alloy. Although iron fasteners have not been located, rusticles and 

unidentifiable conglomerates noted at several locations are likely remnants from deteriorating iron 

fasteners.

The smallest fasteners at the site are sheathing nails. These appear to be hardened copper. They 

are approximately 1 inch (2.54 cm) in length with a flat head and tapering shank. These fasteners 

are spaced on the sheathing approximately 4 inch (10 cm) apart (Figure 10-89 and Figure 10-90).

Five types of larger fasteners have been found and noted on the site. All of these are non-threaded 

spikes or bolts. These types of fasteners are typically used for fastening planking or framing 

components below the waterline. Table 10-5 provides a description of each large fastener type, 

while images of each type are shown in Figure 10-91 to Figure 10-95.

The average shank or shaft diameter of the larger fasteners is 0.75 inch (1.9 cm) with lengths 

between 14-16 in (36.6 to 40.6 cm). The only variation is the Type 4 fastener that has a shank 

diameter of 1 inch (2.54 cm). Desmond (1998) indicates that the 0.75 inch (1.9 cm) diameter bolts 

were used to fasten 3 to 5.5 inch (7.6 to 13.97 cm) thick planking. Bolts having a 1 inch (2.54 cm) 
436

diameter were used to fasten planking or timbers with a thickness of 6 in (15 cm) or greater. The 

bolts with 0.75 inch (1.9 cm) diameter shanks are likely through bolts for attaching the outer 

planking. The larger diameter of the Type 4 bolt suggests it may be a frame or timber bolt rather 

than a through bolt for attaching planking.

Figure 10-89. ROV video capture image of in situ sheathing nails on the 

Ewing Bank Wreck’s starboard hull sheathing.

Figure 10-90. Photograph of sheathing nail from the Ewing Bank Wreck 

(University of West Florida).
437

Table 10-5.

Large fasteners identified at the Ewing Bank Wreck site

Name Type

Shank 

Length 

(inches) Description

Figure 

No. Notes

Type 1 Bolt 16

Rounded shaft non-threaded 

bolt. Rounded head w/square 

underside. Washer attached to 

end of shank. 3/4" shaft 

diameter

10-91

Similar to modern carriage 

bolt/coach bolt. Presence of 

washer could indicate a type of 

forelock bolt.

Type 2 Spike 16

Tapering shaft spike like 

fastener with squarish head. 

Shaft tapers from 3/4" near head 

to 1/2" at point.

10-92

Type 3 Bolt 14

Rounded shaft non-threaded 

bolt with flared head. 3/4" shaft 

diameter.

10-93 Possible evidence of clenching 

noted on some examples.

Type 4 Bolt 16

Rounded shaft non-threaded 

bolt. Flat round head. 1" shaft 

diameter.

10-94

Type 5 Bolt Unknown

Rounded shaft non-threaded 

bolt. 2" flat round head. 3/4" 

shaft diameter.

10-95

Figure 10-91. ROV video capture image of a Type 1 fastener on the Ewing 

Bank Wreck.
438

Figure 10-92. ROV video capture image of a Type 2 fastener on Ewing Bank

Wreck.

Figure 10-93. ROV video capture image of a Type 3 fastener on the Ewing 

Bank Wreck.
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Figure 10-94. ROV video capture image of a Type 4 fastener on the Ewing 

Bank Wreck.

Figure 10-95. ROV video capture image of a Type 5 fastener on the Ewing Bank Wreck.
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10.5.3.4.7 Sheathing

The hull of the Ewing Bank Wreck is sheathed with a cuprous metal. A recovered sample was 

identified as Muntz metal. Other than some irregular stealer pieces near the bow, the sheathing 

appear to be standard rectangular sheets varying in length from approximately 3.3 to 3.94 ft (1 to 

1.2 m) and approximately 11.8 in (30 cm) wide. The majority of sheets have the same dark green 

patina coloration. However, there are several areas on the exposed starboard hull that have lighter 

colored sheets. The difference in sheet coloration suggests that these areas may represent where 

worn out or damage sheathing has been repaired (Figure 10-96).

There is roughly a 2-inch (5 cm) overlap between sheets for fastening. Fasteners on the overlapping 

edges are spaced roughly 2 in (5 cm) apart. The sheathing is held to the outer planking by hardened 

copper fasteners, which are staggered between rows forming a typical diamond nail pattern. The

fastener spacing is 4 in (10 cm) between nails. Fasteners on the overlapping edges are spaced 2 in

(5 cm) apart.

Diagonal foiling (buckling) occurs on the sheathing (Figure 10-97). This foiling has been observed 

on other deepwater wrecks with sheathed hulls. Why the sheathing buckles is not fully understood, 

but it may result from compression of the wood at depth or the activity of anaerobic bacteria. The 

foiling likely occurs in a diagonal line because it follows the pattern of the nails holding the 

sheathing to the hull planking.

Figure 10-96. ROV video capture image showing Muntz metal copper 

sheathing and possible repair areas on the Ewing Bank Wreck’s 

starboard hull.
441

Figure 10-97. ROV video capture showing diagonal foiling of sheathing on 

the Ewing Bank Wreck’s starboard stern.

10.5.3.4.8 Miscellaneous Ship Components

Although most of the materials on the Ewing Bank Wreck are related directly to the vessel’s 

construction, there are miscellaneous ship components or remnants of them visible at the site. 

These include the ballast pile, sections of pipe, a ladder-like remnant, and a flange assembly.

The ballast pile is the largest of these non-construction components (Figure 10-98). The pile 

extends across the width of the wreck from the forecastle area to just forward of the stern tuck. 

The video data suggests the ballast pile maybe 11.8 to 24 in (30 to 60 cm)deep. The ballast stones 

appear to be irregular in shape. The size of the ballast stones, based on those visible in the video 

data, ranges from less than 11.8 in (30 cm) up to as much as 3.2 ft (1 m) in length. 
442

Figure 10-98. AUV photograph of the Ewing Bank Wreck’s stone ballast 

partially covered in silt (C & C Technologies, Inc.).

Other non-construction components include sections of pipe on the interior of the vessel. One 

section of pipe overlays the ballast pile along the centerline near the middle of the wreck (Figure 

10-99 and Figure 10-100). This pipe is approximately 16.4 ft (5 m) long and has a curved section 

at the end nearest the stern that protrudes 11.8 in (30 cm) up from the top of the ballast pile. The 

second segment of pipe is near the forward end of the ballast pile extending diagonally from the 

centerline aft to the wreck’s port side (Figure 10-101). It is broken into three pieces that have a 

combined length of 11.8 ft (3.6 m). Both sections of pipe have about a 4 inch (10 cm) outside 

diameter and appear to be made of ferrous material. The total length of both pipe segments is 28.2 

ft (8.6 m). The proximity of pipe segments of the same diameter in proximity to each other 

indicates that they were likely connected at one time. Although the exact purpose of these pipes 

it is not known, it is speculated that they may be related to the ship’s bilge pump system.
443

Figure 10-99. ROV video capture image of pipe remnant in Ewing Bank

Wrecks interior hull (view to port).

Figure 10-100. AUV camera photograph off pipe remnant, ballast, and 2009 

microbiological experiment in the Ewing Bank Wreck’s interior aft 

hull (Image C & C Technologies, Inc.).
444

Figure 10-101. AUV camera photograph of pipe remnant in the Ewing Bank

Wreck’s forward hull (Image C & C Technologies, Inc.).

Between the two larger sections of pipe, is a wooden remnant that resembles a ladder (Figure 

10-102). It has two parallel slats of wood 1.9 to 2.3 ft (0.60 to 0.70 m) in length connect by two 

extant rungs 11.8 to 13.8 in (30 to 35 cm) in length. The rungs are spaced about 11.8 in (30 cm) 

apart. No similar structure has been found on the wreck site and its actual role on the ship remains 

unknown. This could represent the remnants of a bulkhead structure or possibly a hatch ladder.
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Figure 10-102. AUV camera photograph of ladder-like object in the Ewing 

Bank Wreck's interior hull (C & C Technologies, Inc.).

The last and most intriguing ship components on the Ewing Bank Wreck are two flange assemblies 

(Figure 10-103). The flange assemblies rest on the interior port stern quarter just past where the 

hull turns inward towards the stern. Each flange has a section of lead pipe attached to it. The 

flanges have an outside diameter of 5.9 in(15 cm). The attached segments of lead pipe are 

approximately 4 inch (10 cm) outside diameter. The overall length of the assembly is difficult to 

determine because the leg piping is folded and flattened, but conservative estimates based on the 

ROV footage indicate the assembly is a least 2.5 ft (0.75 m) long. It is interesting to note that the 

estimated diameter of the lead piping is similar to that of the ferrous pipes discussed previously. 

It is possible that both those pipe segments and the flange assembly represent the last vestiges of 

the Ewing Bank Wreck’s bilge pump system.
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Figure 10-103. ROV video capture image of flange assemblies and pipe remnants on the Ewing 

Bank Wreck's port stern.

10.5.3.4.9 Artifacts

There is a noticeable dearth of material culture remains on the Ewing Bank Wreck. The only 

artifacts documented on the wreck related to daily activities of passengers and crew is a 

concentration of ceramics near the port stern interior (Figure 10-104). The data suggests the 

concentration consists of 12 to 15 fragmented vessels of various forms, including cups, plates, and 

at least one platter. Most of the ceramics appear to be undecorated white paste wares, but some 

fragments of molded-and-flow blue or transfer-print-decorated wares were also noted on the site 

(Figure 10-105). The condition, location, and variety of materials in the concentration indicate 

that the materials were likely discarded in the bilge area before the vessel sank.
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Figure 10-104. ROV video capture image of ceramic concentration at 

the Ewing Bank Wreck’s port stern.

Figure 10-105. ROV video capture image of ceramic container and 

flow blue decorated plate fragmenton the Ewing Bank

Wreck.
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10.5.3.5 Recovered Artifacts

Four artifacts—a partial ceramic vessel, a ballast stone, a net sample, and sample of metal 

sheathing and fastener—were recovered from the Ewing Bank Wreck site during the 2009 

investigation. The artifacts were conserved at the UWF Archaeology Institute’s conservation lab 

in Pensacola, Florida and the conservation report can be found in Appendix E-2.

A single ceramic vessel recovered from the port stern interior of the Ewing Bank Wreck was only 

partially intact (Figure 10-106). The recovered portion measures 3.8 in (9.76 cm) in length, 3.8 in

(9.76 cm) in diameter, and represents approximately two-thirds of the whole vessel. It is round in 

shape, tapers slightly towards its base, and has a cameo-decorated ear or lug handle. There are no 

marks indicating the maker or date of manufacture on the cup.

Figure 10-106. Photograph and drawing of ceramic piece recovered from the Ewing Bank

Wreck showing cameo design on lug handle (University of West Florida).

The ceramic piece recovered from the Ewing Bank Wreck is molded utilitarian white ironstone, 

often referred to in the vernacular as “hotel ware”. White ironstones were introduced in the 1840s 

but by the 1870s and 1880s ironstone production was mainly the heavy utilitarian wares. The 

shape of the piece indicates a Gothic Period (1850-1870) influence, while the presence of ears or 

lugs on the sides suggest it may be a sugar bowl or a toilet ware such as a shaving mug (Wetherbee, 

1996; Mansberger, 2011). No maker’s mark or date are on the piece, however, the cameo design 

on the lug handle appears to be a molded decoration known as “Pharaoh Cameo”. The Pharaoh 

Cameo design (Figure 10-107) was introduced by J & G Meakin in the 1870s and 1880s (White 

Ironstone Society, 2011), but like most ware designs from the period, may have been copied by 

other manufacturers. 
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Figure 10-107. A J & G Meakin "Pharaoh" cameo decorated sugar bowl (Image courtesy of the 

White Ironstone Society).

One ballast stone sample was recovered from the starboard amidships area of the Ewing Bank site 

for analysis. The ballast stone was bisected to examine the interior (Figure 10-108). The ballast 

stone is yellowish in color with some darker staining on the portion that was buried in the sediment. 

An acid test using a hydrochloric acid mixture, carried out at the C&C Houston office, on a section 

of recovered ballast stone determined it is a calcareous stone most likely limestone. On the interior 

of the stone are several small cracks with what appears to be crystalline deposits (Figure 10-109). 

To date, the origin of the ballast has not been determined.
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Figure 10-108. Photograph of ballast stone recovered from Ewing Bank

Wreck (University of West Florida).

Figure 10-109. Photograph showing crystalline structure on interior of 

ballast stone from the Ewing Bank Wreck.
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There is evidence of intrusive anthropogenic material on the Ewing Bank Wreck Site. Most of the 

material is a long line that likely drifted into the wreck. One piece of intrusive material, a section 

of net, does not appear to have drifted into the wreck. The net, located off the wreck’s port stern, 

is partially covered by a section of hull lying on the seafloor. A piece of this net was recovered 

during 2009 (Figure 10-110 and Figure 10-111). The net was analyzed at UWF, unfortunately a 

miscommunication between field personnel led to the net being discarded. The UWF analysis 

indicated that this is a modern section of netting. The net fragment had a brownish to yellowish 

brown color and, according to the UWF Conservation report (2011); microscopic examination 

determined it was made of “modern plastic” material. This suggests a braided monofilament or 

polypropylene material. It is thought that the net is a remnant of a deepwater trawl net that snagged 

on a piece of the stern that once extended higher above the seafloor than it does today.

Figure 10-110. Photograph of net in Ewing Bank Wreck's stern debris zone (Aquapix Camera 

Image, Lophelia II, 2009: Deepwater Coral Expedition: Rigs, Reefs, and Wrecks).
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Figure 10-111. Photograph of net recovered from Ewing Bank Wreck (University of West 

Florida).

The Ewing Bank Wreck’s hull is sheathed in a cuprous metal. During the 2009 investigation a 

sample of sheathing including a fastener and wood was recovered near the starboard bow of the 

wreck (Figure 10-112 and Figure 10-113). The sample underwent conservation and analysis at 

the UWF Conservation lab. Post-conservation examination of the sheathing confirmed the fastener 

spacing of 4 in (10 cm) observed on the video, except in the overlap areas where the spacing is 

approximately 2 in (5 cm) (Figure 10-112). Post-conservation examination of the sheathing also 

revealed a maker’s stamp on the copper (Figure 10-113). The maker’s stamp is composed of a 

large ovoid circle around a smaller ovoid circle. Between the inner and outer circles, the word 

“MUNTZ” is clearly visible, but the remaining text is undecipherable. The inner circle contains 

images of 3 crowns with the number “18” beneath them. The presence of the maker’s stamp 

identifies the sheathing as Muntz Metal. This identification was confirmed using a hand-held 

portable X-Ray Fluorescence device which determined the percentage of metals in the sheathing 

were consistent with the 60/40 copper-to-zinc ratios used in Muntz metal.
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Figure 10-112. Photograph of Muntz Metal sheathing recovered from 

Ewing Bank Wreck Site (University of West Florida).

Figure 10-113. Close-up of Muntz Metal maker's stamp on sheathing sample 

recovered from Ewing Bank Wreck (University of West Florida).
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10.5.3.6 Site Preservation

The wreck site is currently in a low to moderate state of preservation. The hull is partially intact

where it is sheathed from just below the waterline to the keel. Although the sheathing’s antibiofouling properties have provided some protection to the hull sections that are in direct contact 

with it, much of the wood structure on the interior highly is degraded and there are no extant hull 

remains above the copper sheathing. This is consistent with other GoM deep-water discoveries, 

where remains of wooden hull are present in conjunction with copper sheathing and largely absent 

above the line of sheathing. The bow and stern are both partly intact, however, the stern does 

exhibit some damage, most likely anthropogenic disturbance to the wreck caused by trawling 

activities. The vessel is heeled over to port, leaving the outer starboard hull partially exposed 

down to the turn-of-the-bilge. Some damage to the copper sheathing was observed on this part of 

the wreck, but the sheathing appears to be mostly intact. The port side is partially buried by a berm 

of sediment that formed after the ship sank. This berm, which likely contains stratified hull 

remains, obscures much of the port hull exterior, so an accurate preservation assessment of this 

section was not possible. It is likely, however, that this section of the hull, protected by the 

sediments, remains relatively intact.

In an effort to monitor the wreck’s preservation, a short-term etching microbial tester and a long -

erm WW-GUCCI platform were deployed at the site to test microbial activity and to monitor 

deterioration rates. The etching tester was not left in place long enough for a reaction to occur or 

provide information on the level of microbial activity at the site. The WW-GUCCI platform was

deployed amidships near a section of pipe along the keelson, and will provide long term indications

of site deterioration rates from microbial and chemical deterioration. Reexamination of the test 

platform in the future will be invaluable in assessing long-term preservation of the Ewing Bank

Wreck site.

10.5.4 Green Lantern Wreck Site

10.5.4.1 Historical Background of the Green Lantern Wreck

The Green Lantern Wreck Site is the remains of a wooden sailing vessel dating from the late 

nineteenth to early twentieth century. Since its discovery in 1996, there have been a deep-tow and 

an AUV survey of the site, several industry sponsored ROV investigations, and two government 

sponsored ROV investigations. Archival research has failed to identify the name or nationality of 

this shipwreck. 

10.5.4.2 Field Investigations

10.5.4.2.1 Discovery and Exploration

C&C and William & Associates discovered the shipwreck in 1996 while conducting a pipeline 

survey for BP Exploration Inc. The survey used a deep-tow AMS 120 Sonar Mapping System, 

which included 120 kHz side-scan sonar (George 1996). In March 2004, C&C conducted an 

archaeological, engineering and hazard survey for a proposed pipeline route for GulfTerra Energy 

Partners, L.P. (GulfTerra) using the C-Surveyor I AUV, which imaged the shipwreck. In 

September 2004, GulfTerra sponsored the first ROV investigation of the wreck site led by a 
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professional marine archaeologist. A reconnaissance of the site and surrounding area revealed a 

copper-clad sailing vessel that appeared to date from the nineteenth century. Several features and 

artifacts were documented during the ROV survey, including a navigation lantern found lying on 

the seafloor near the aft starboard side of the wreckage (Figure 10-114). The word “ESTRIBOR,” 

which is Spanish for “starboard,” is stamped on the face of the lantern. Thereafter the site was 

referred to as the Green Lantern Wreck in reference to the green/starboard lantern (Church et al 

2004). 

Figure 10-114. Starboard Signal Lantern near the Stern.

Subsequently, two more oil and gas industry ROV investigations of the site took place in July 2007 

and April 2010. These investigations were required by the BOEM/BSEE (MMS at the time) as 

monitoring efforts associated with infrastructure installation near the area. 

10.5.4.2.2 Lophelia II: Reefs, Rigs, and Wrecks 2008 Field Cruise

A site investigation was planned during the Lophelia II: Reefs, Rigs, Wrecks 2008 Field Cruise. 

Poor visibility and strong current at the seafloor, however, made investigating the site impossible 

at that time. The 2008 research team deployed an ROV at the site and made visual contact with 

the stern of the shipwreck. Several attempts were made to fly over the site, but the dive was 

aborted because of adverse conditions. 

10.5.4.2.3 Lophelia II: Reefs, Rigs, and Wrecks 2009 Field Cruise

In September 2009, an ROV investigation of the Green Lantern Wreck was conducted as part of 

the Lophelia II: Reefs, Rigs, and Wrecks Study. Over an approximate 20-hour period (17.5 hours 

on the wreck site) on September 8 and 9, 2009, the Lophelia II team used Woods Hole 

Oceanographic Institution’s Jason II ROV launched from the NOAA Research Vessel Ronald H. 

Brown to document the shipwreck site. Visibility on-site was good during the 2009 investigation, 
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equaling or exceeding 8 m. Limited cultural material was collected during the project to help 

better understand the wreck site.

The 2009 investigation consisted of an initial reconnaissance survey, site mosaic transects, detailed 

inspection of significant features (both biological and archeological), deploying biological 

experiments, and artifact collection. The one-and-half hour reconnaissance consisted of a 

preliminary examination around the full perimeter of the main hull to assess its current condition 

and to prioritize areas for additional investigation and material collection. The reconnaissance 

began at the stern and proceeded up the starboard side, moving slowly toward the bow. After an 

examination of the bow, the ROV moved along the port side towards the stern. The ROV then 

moved up the centerline of the vessel from stern to bow imaging the interior of the hull. 

Following the reconnaissance, 14 parallel track-lines at 1 meter spacing were flown over the main 

hull taking, a serious of evenly spaced still photographs for mosaic purposes. The digital still 

camera was mounted in a vertical viewing position and the ROV flown between 4.9 and 5.3 m

altitude during transects. Approximately three hours were spent conducting the photo mosaic 

transects.

Biological operations were conducted over the next six and a half hours, including biological 

transects, collecting sediment cores, and detailed biological documentation. Three parallel 

biological transects were run 100 m east of the wreck site. Sediment core samples were collected 

at distances varying from 100 m away to 10 m from the wreck site. Detailed photographs and 

measurements were taken of coral and other features of biological interest at various areas of the 

wreck.

Following the biological investigation, close-up examination was conducted of archaeological 

features along with the deployment of short-term and long-term microbiological experiments near 

the starboard bow (approximately 6.5 m aft of the stem). Approximately two hours were allocated 

for those tasks. The next approximately seven hours included rusticle collection, retrieval of the 

short-term microbiology experiment, and artifact recovery. Six artifacts were recovered, which 

are described the artifact recovery section below.

10.5.4.3 Geographical Setting 

The Green Lantern Wreck is in the north-central portion of the Green Canyon area of the GoM

(Figure 10-115). The project area is located south-southwest of New Orleans, Louisiana on the 

upper continental slope. The topography of the region is characterized by diapiric highs and basinlike topography. The seafloor across the site, however, dips southward at a gradient of less than 1 

degree. 

The geologic setting of the northern GoM is the result of extensive sediment loading and buoyant 

salt movement. Diapirs, ridges, domes, and anticlines of Mid-Jurassic age (Mann, 1987) underlay 

the entire Texas-Louisiana slope. Salt intrusions have dramatically influenced the regional 

geology of the outer shelf and upper slope Gulf Coast areas. Many of these mobile salt bodies 

protrude through the thick Pleistocene deposits and exist very near the seafloor. These salt bodies 

have uplifted, deformed, and faulted the overlying deposits and have created bathymetric highs on 

the seafloor. Authigenic carbonates, which are derived from bacterial reduction of hydrocarbons 
457

escaping through the seafloor, can be found in the deeper portions of the continental shelf and 

continental slope. The diapiric salt of the upper slope has migrated downslope, evolving into 

ridges, massifs, and lobes or tongues in the lower slope (Lee et al., 1989).

10.5.4.4

10.5.4.5 Discussion of Archaeological Findings

Figure 10-115. Green Lantern Wreck Site drawing based on ROV investigations.
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10.5.4.5.1 Physical Site

The vessel is oriented with the bow pointing southeast and the stern northwest (Figure 10-115). 

Average water depth at the site is 915 m Below Sea Level (BSL). The vessel measures 69 ft (21 

m) length and approximately 23 ft (7 m) in width at beam indicating a 3:1 length-to-beam ratio. 

Individual artifacts, rigging, and other hull material are scattered out from the hull making the 

overall measurement of the site 108 × 33 ft (33 × 10 m). A dark -olored glass bottle was 

documented in 2004 lying approximately 23 m west of the bow (no photograph available). Other 

than the one bottle, no additional artifacts have been observed away from the main site. 

The wreck is sitting on an even keel with 3 to 5 ft (1 to 1.5 m) of relief along the starboard gunwale 

and 1 meter or less along the port side. Remnants of the double frames are visible along the aft 

starboard side (Figure 10-116). The exposed frames, at what is believed to be the first and second 

futtock, have a room and space of 20 in (50 cm) (the room is approximately 11 in (29 cm) and the 

space is approximately 8 in (21 cm)). The sided dimension of each frame in the pair is from 5.5 

to 6 in (14 to 15 cm). The molded dimension could not be measured because of the angle of view 

and buildup of sediment between the frames. 

Figure 10-116. View of aft starboard frames and ceramic dish at the Green Lantern Wreck.

10.5.4.5.2 Sheathing

The hull is sheathed in copper or a copper alloy such as Muntz metal, but a sheathing sample was 

not collected for analysis at this site. The sheathing appears to be standard 48×14 inch (121.9 × 

35.5 cm) sheets with 1 to 1.5 in (2.5 to 3.8 cm) overlap between sheets. The sheathing is held to 
459

the hull by copper or copper alloy fasteners, which are staggered between rows forming a typical 

diamond nail pattern. The fasteners spacing is 5.25 in (13.3 cm) between nails horizontally and 

3.5 in (8.9 cm) diagonally. Diagonal foiling (buckling) is observed along the copper or copper 

alloy sheathing, which is typical of copper-sheathed vessels found in deep-water (Figure 10-117). 

The reason the sheathing becomes buckled is not fully known, but is possibly related to either 

compression of the wood at depth or the activity of anaerobic bacteria (See Viosca Knoll Site 

analysis in Section 4.1 and the DBI microbial report in Appendix E-1). 

Figure 10-117. Diagonal foiling observed in sheathing (tarboard side) on the Green Lantern

Wreck.

10.5.4.5.3 The Bow

The stempost (remnants of the post and apron) stands approximately 9 ft (2.7 m) proud of the 

seafloor and 7 ft (2 m) beyond the top edge of the copper sheathing (Figure 10-118). The upper 

remnants of the stem measure 20 in (50 cm) molded (approximately 22 in (57 cm) just above the 

sheathing) and 11 in (28 cm) sided (upper and lower). Three bobstays fittings are present. The 

two lower fittings have four-sided nuts and bolts fastening the hardware together, but the upper 

fitting has a six-sided nut and bolt, which may represent a repair (Figure 10-119). The gripe or 

cutwater piece is missing above the bobstays fittings, but two iron drift pins outline where the edge 

of the gripe would have been. The missing section may also be where the gripe transitioned into 

the head knee. 

Two draft marks are visible on the starboard side of the stem (Figure 10-118 and Figure 10-119). 

The marks are one foot apart. The lower is the 5-foot mark represented by Roman numeral “V” 

and the upper is the 6-foot mark represented by Roman numeral “VI.” Part of the upper mark is 

nearly obscured by rusticle growth. The 5-foot mark is approximately 60 cm above the mud line. 

No draft mark or nail pattern indicating another draft mark are visible below the 5-foot mark.
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Figure 10-118. Bow of the Green Lantern Wreck (view from starboard side).

Figure 10-119. Close-up of bobstay fittings and draft marks on the Green Lantern Wreck
461

The ship’s windlass is lying on the seafloor against the port side of the bow (Figure 10-120). It

appears to be an iron patent windlass. Portions of the warping ends and driving wheel are visible 

through the rusticles, other biological growth, and entangled rigging. Chain is visible around the 

forward edge, which is likely the port side end of the windlass. Chain is also present among the 

seafloor debris on the starboard side opposite the windlass. The chain links measure approximately 

5 in (13 cm) each.

Figure 10-120. Windlass lying to the port bow of the Green Lantern Wreck.

10.5.4.5.4 Rigging

The head rigging is visible on the seafloor forward of the stem. Visible portions of this rigging 

extend approximately 8.5 m forward of the bow. Possible gammon irons covered with biofouling 

are partially visible just forward of the stem. The bow sprit cap is present 4 m from the stem.

Rigging for a single mast is visible to the port side of the head rig. The visible portion of the mast 

rigging extends approximately 12 m from the hull. The furthest visible portion of the rigging 

includes the mast cap. This rigging runs across the windlass and back towards a mast rig lying on 

the hull at midship. The mast ring is located 4.7 m aft of the stem post. The distance from the 

mast cap to the mast ring is 15 m. 

During the initial investigation of the site in 2004, a faint line of shell hash was noted running in a 

line from the mast cap towards the hull. That line of shell hash likely denoted the location where 

the mast was laying as it slowly disintegrated or was consumed by microbes and invertebrates. 

The shell remnants have become obscured by sediment and were not visible during the 2009 

investigation. 
462

10.5.4.5.5 Between the Bow and Stern

Most of the port hull and sheathing is flush with the seafloor aft of the windlass. The starboard 

side, however, exhibits approximately a meter of relief from the bow to the stern. Many of the 

loose artifacts were observed along the starboard side near the gunwale or lying on the seafloor 

near the stern, with some material also located on the seafloor near the bow. 

A mass of various remains and internal components are present along the starboard side between 

the stem and mast ring. Most are unidentifiable due to deterioration and biofouling. Some 

recognizable parts include chain, rigging, and a coil of possible copper tubing (Figure 10-121). 

Ferrous material is present within these remains, as is evident from reddish-orange rust and rusticle 

formations. Some of these components could be part of the windlass bitt and anchor chain. 

Approximately 1 meter aft of this “mass,” a single fork was found lying near the starboard gunnel. 

The fork is one of the artifacts recovered and is discussed in Section 10.5.4.5 and the Artifact 

Conservation Report (Appendix E-2).

Figure 10-121. Copper tubing and possible windlass bitt (upside down) at the Green Lantern

Wreck site.

A bell was located approximate 5.5 m aft of the fork (11.5 m from the bow and 9 m from the stern). 

It is located 1 meter inboard and partially covered with other material. It is a small bell measuring 

6 in (15 cm) in diameter and 6 in (15 cm) tall. The bell is one of the artifacts recovered and is 

discussed in Section 10.5.4.5 and the Artifact Conservation Report (Appendix E-2). A round sheet 

of glass stands on end against the hull just outboard of the bell (Figure 10-122). The glass is 
463

approximately 11 in (28 cm) in diameter with at least 4 in (10 cm) extending above the height of 

the copper sheathing.

Figure 10-122. Small bell and round sheet of glass (setting on edge) at the Green Lantern Wreck 

site.

One of the vessel’s signal lanterns (Figure 10-123) is located approximately 2.5 m aft of the bell 

and approximately 6 m forward of the stern. It is located 0.7 m inboard along the starboard side. 

This lantern is thought to be the port signal lamp because the starboard lantern is located on the 

seafloor near the stern (4.5 m away). 

Figure 10-123. Port signal lantern of the Green Lantern Wreck.
464

10.5.4.5.6 The Stern

Four frame pairs are exposed near the stern. As previously mentioned the exposed sections are 

believed to be at the first and second futtock. A ceramic dish was located on the starboard side 

just aft of the exposed frames (Figure 10-116). The dish was face down approximately 0.7 m

inboard and 2.5 m from the sternpost. The dish is one of the artifacts recovered and is discussed 

in Section 10.5.4.5 and the Artifact Conservation Report (Appendix E-2). Directly opposite the 

dish on the port side, is a 6.5 foot (2 m) section of bent pipe. It is bent where it crosses the edge 

of the sheathing. The possible remains of a bilge pump or other machinery is laying on the seafloor 

near the end of the pipe and the two appear to be associated (Figure 10-124). The possible pump 

head is located at the edge of the gunwale remains, just outside of the sheathing.

The rudder and rudder post are mostly intact. The majority of the rudder is buried, but the upper 

gudgeon and pintle is visible (Figure 10-125). The vessel appears to have been steered by a tiller 

and the remnants are visible of the hardware that would have attached the tiller to the rudder post. 

The sternpost is gone above the copper sheathing. There is, however, a structural component 

forward of the sternpost that helps indicate the shape and dimensions of the sternpost. The molded 

dimension of the sternpost was approximately 15 in (38 cm) and forward-sided dimension was 18 

in (45 cm) with the aft-sided dimension measuring approximately 8 in (20 cm).

Figure 10-124. Possible bilge pump and pipe at the Green Lantern Wreck site.
465

Figure 10-125. Port side view of the rudder, and gudgeon and pintle at the Green Lantern Wreck 

site.

The structural component forward of the sternpost is notably more intact than other structural 

components of the stern (Figure 10-125). This piece may be metal or of a different wood type than 

the other parts of the hull, which has allowed it to survive longer. The exact function is not certain, 

but it can best be described as a crutch. The possible crutch stands approximately 12 in (30 cm) 

above the copper sheathing. It measures 33 in (84 cm) wide at it widest point and 5 in (12 cm) 

thick at the middle of the top surface. It is notched to fit around the forward edge of the sternpost 

and shaped to fit into the port and starboard sides where they begin to come together at the stern 

similar to a transom piece.

A copious amount of wreck material and individual artifacts are concentrated on the seafloor at 

the stern, particularly to the starboard side. The various objects include several wooden sheaves, 

copper or brass drift pins, glassware, the starboard signal lantern, and numerous other unidentified 

artifacts. Among these items, the starboard lantern, a sheave, and round cap orplug suspected to 

be associated with the lantern were part of the artifacts recovered. They are discussed in Section 

10.5.4.5 and the Artifact Conservation Report (Appendix E-2).
466

10.5.4.6 Recovered Artifacts

Six artifacts were recovered from the Green Lantern Wreck site during the 2009 investigation 

including a bell, wooden sheave, metal fork, ceramic dish, starboard signal lantern, and copper cap

or plug. The artifacts were conserved at the UWF Archaeology Institute’s conservation lab in 

Pensacola, Florida and the conservation report can be found in Appendix E-2. 

The bell (Artifact: MMS09.373.C.005) is a small bronze bell measuring 6 in (15 cm) in diameter 

(Figure 10-126). There are no discernible maker’s marks on the bell. Likewise, the wooden sheave 

is a typical block sheave, which measures 8 in (20 cm) in diameter and 13.5 in (34 cm) thick 

(Figure 10-127). It was thought that it might be a patent sheave prior to recovery and was only 

discovered to be an indistinct wooden sheave after recovery. 

Figure 10-126. Bell recovered from the Green Lantern Wreck (post-conservation).
467

Figure 10-127. Wooden sheave recovered from the Green Lantern Wreck 

(pre-conservation).

The metal fork (Artifact: MMS09.373.M.002) has four prongs and measures 7 in (17.5 cm) long 

(Figure 10-128). It is made of a metal alloyed composed primarily of copper, zinc, nickel, iron, 

and tin. “SIM... GEORGE H. ROGERS” is engraved on the back indicating it was made by the 

Simeon L. & George H. Rogers Co. The Simeon L. & George H. Rogers Co. began manufactured 

silver flatware in Hartford, Connecticut in 1901. The company was acquired by Wm. A. Rogers 

Limited in 1918 (Goodwin, et al. 1901; and Silver, 2013).
468

Figure 10-128. Fork recovered from the Green Lantern Wreck

The small white ceramic dish (Artifact: MMS09.373.C.006) measures 5.5 in (14 cm) in diameter 

(Figure 10-129). It bears the makers mark of Wood and Sons Ltd. on the underside. The mark 

consists of the Royal Arms with “IRONSTONE CHINA” above and “WOOD AND SON LTD, 

ENGLAND” below. Wood and Sons was established as an earthenware manufacturer in Burslem, 

England in 1865. The company was incorporated in 1910 as Wood and Sons Ltd. and began using 

this maker’s maker at that time (Perry, 2010). 

Figure 10-129. Ironstone plate recovered from the Green Lantern Wreck.

The lantern measures 17 in (43 cm) tall and 9 in (23 cm) wide. As previously mentioned, the word 

““ESTRIBOR,” (Spanish for starboard) is written on the lantern’s door (Figure 10-130). The body 
469

of the lantern is made primarily of copper. A small “Broad Arrow” made of copper was attached 

to the body, but became separated during conservation. The lens is made of two sections of green 

glass. One says “London” and the other says “Miller’s Patent.” 

Figure 10-130. Navigation lantern recovered from the Green 

Lantern Wreck.

The small round cap or plug measures 4.5 in (11.6 cm) in diameter and 1.7 in (4.3 cm) thick (Figure 

10-131). It is composed primarily of copper lead and zinc. Originally thought to be a container, 

it was discovered during conservation that it is not meant to open and possibly serves as some type 

of plug. It was recovered directly adjacent to the lantern and may be associated. 

Figure 10-131. Copper plug from the Green Lantern Wreck (post-conservation).
470

10.5.4.7 Site Preservation

The wreck site is currently in a moderate state of preservation. The hull is partially intact where 

it is sheathed with copper or Muntz metal. The sheathing’s anti-biofouling properties likely offer 

some protection to the hull sections in direct contact with it. This is consistent with other GoM

deep-water discoveries, where remnants of the wooden hull are present in conjunction with copper 

sheathing and largely absent above the line of sheathing. The bow is partly intact as is the stern. 

Based on the draft marks, approximately 4 ft (1.2 m) of the lower hull is buried beneath the 

sediment.

A short-term etching microbial tester and la ong-term WW-GUCCI platform were deployed just 

forward of midship along the starboard side to test microbial activity and to monitor deterioration 

rates (Figure 10-132). The etching tester deployed at this site was the only shortterm tester left in 

place long enough for a reaction to occur. The etching tester remained on the site for 27 hours and 

revealed a high level of microbial activity. The preliminary results indicate a high rate of 

biological determination can be expected at the site. The WW-GUCCI platform is designed to 

provide a long-term indication of site deterioration rates from microbial and chemical 

deterioration. Reexamination of the test platform in the future will be invaluable in assessing longterm preservation of the Green Lantern Wreck site.

Figure 10-132. GUCCI Microbial Test Platform deployed along the starboard side of the Green 

Lantern Wreck site.

10.5.5 Gulfoil wreck site

10.5.5.1 Historical Background of the Gulfoil

Built by New York Shipbuilding Company in Camden, New Jersey, Gulfoil’s keel was laid on 

February 22, 1912 and was completed on August 29, 1912 (Figure 10-133 and Figure 10-134). 

The ship had a length of 406 ft (123.8 m), a breadth of 51 ft (15.5 m), a depth of 30 ft (9.1 m), and 
471

was 5,188 gross tons (New York Shipbuilding Company 1911). Henry G. Morse established The 

New York Shipbuilding Company in 1900. He chose Camden, New Jersey as the site for his yard 

because of the availability of good land, its proximity to railroad lines, and a large labor force of 

experienced shipyard workers. Morse employed a five-principal business plan at the New York 

Shipbuilding Company. Morse’s plan incorporated a mold-lift template system for hull steel, 

prefabrication of relatively large structural components, the use of overhead cranes to move 

prefabricated structures, covered ship-building ways and outfitting basins to allow year-round 

work, and the installation of heavy machinery using overhead cranes before launching (New York 

Shipbuilding Company 1911). 

Figure 10-133. Gulfoil circa 1912.(Independence Seaport Museum).

Utilization of these five principles at the New York Shipbuilding Company allowed faster 

production of all vessel types. The efficiency of Morse’s five principled process led New York 

Shipbuilding Company to become the third largest shipbuilding firm in the world by World War 

I. By World War II, the New York Shipbuilding Company had built 44 active-duty naval ships 

and over the course of the war supplied another 26 combat vessels to the United States Navy. To 

meet increased wartime manufacturing demand, the New York Shipbuilding Company employed 

30,000 workers. During World War II, the Camden Yard produced a variety of vessels for the 

allied forces including three seaplane tenders, two destroyer tenders, eight light cruisers, nine light 

aircraft carriers, one repair ship, two battle cruisers, and one battleship (New York Shipbuilding 

1949). After WWII, the company built a few nuclear submarines, but these efforts were not 

enough to keep the company financially solvent. In 1967, New York Shipbuilding, unable to 

compete in the industry, closed for business (Kube-McDowell 2009).
472

Figure 10-134. Architectural drawing of the Gulfoil.(International Marine Engineering 1912).
473

Among the many ships built by the New York Shipbuilding Company at Camden before World 

War I, was a series of tankers for the Gulf Oil Corporation. The Gulf Oil Corporation was an 

expansion of the J. M. Guffey Petroleum Company. It was founded in 1901 after oil was discovered 

at Spindletop, Texas. Gulf Oil promoted the idea of branded product sales by selling fuel from 

pumps marked with the distinctive Orange Disk logo. Gulf Oil grew steadily in the inter-war years 

with the company being characterized by its vertically integrated business activities. The company 

supported multiple undertakings including exploration, production, transportation, refining, and 

marketing. One of Gulf's initial visionary steps was the introduction of the first drive-in service 

station in 1911 (Gulf Oil International 2011; Clark and Odintz 2012 ).

Today, Gulf Oil International (GOI) holds operations in over 70 countries. In the U.S., Gulf Oil 

is owned by Cumberland Farms Inc, which has licensing agreements with various independent 

distributors to use the “Gulf” brand to sell oil products (Gulf Oil International 2011).

The ships built for the Gulf Oil Corporation by the New York Shipbuilding Company included the 

tanker Gulfoil. Gulfoil was the first American-built oil tanker to incorporate the Isherwood system 

of ship construction (International Marine Engineering 1912, (Figure 10-135). This method of 

construction, developed by British naval architect Joseph Isherwood, uses longitudinal framing 

instead of the traditional transverse framing carried over from wooden ship construction. 

Isherwood obtained a British patent in 1906 and an American patent on June 11, 1912 (U.S. Patent 

Office 1912; Groner 1922) for the system of using a series of longitudinal frames in large vessels 

to prevent buckling (hogging/sagging). The longitudinal frames traverse the length of the vessel 

bottom, sides, and beneath the decks. They are connected to transverse bulkheads via brackets 

essentially making the transverse frame a single continuous piece. Isherwood’s system creates 

70.6 percent more strength at the bilge connection which is constantly subjected to severe stress. 

(Flodin 1919).
474

Figure 10-135. Figure of Isherwood System of Ship 

Construction. (U.S. patent 1,029,546 

1912).

The method of using longitudinal frames has many advantages beyond the added strength. A ship 

built on the Isherwood system uses 7 percent less steel than a ship of the same type built using 

transverse framing. This 7 percent savings in steel equates to the ship possessing less dead weight 

which means the longitudinally framed vessel has a greater carrying capacity. Longitudinal frames 

allow for more space between transverse bulkheads by fitting the longitudinal frames directly to 

the decks and hull plating. This increase in space creates better ventilation and easier below-deck 

maintenance access. Longitudinal frames also reduce vibration. The reduction in vibration 

increases the longevity of the vessel because it reduces friction on connecting parts such as rivets 

and welds (Flodin 1919). 
475

The Gulfoil was initially employed to transport refined oil, crude oil, and asphalt from The Gulf 

Refining Company’s docks in Port Arthur, TX to ports along the U.S. Eastern Seaboard. During 

U.S. involvement in World War I, ship movements were blocked from public record. As a result, 

Gulfoil’s movements from March 13, 1917 until August 24, 1920 have not been located (Fuel Oil 

1914, 1915, 1916; Oil and Gas 1917). During the inter-war years, Gulfoil was involved in the 

Mexico oil trade, transporting oil from Tampico, Mexico to Port Arthur, TX (Oil Trade 1918, 

1919, 1920). The Gulfoil’s movements prior to America’s entry into World War II have not been 

located. It is known, however, that Gulfoil was en route from Port Arthur to New York when it 

was sunk by U-506 (Wiggins 1995).

When Grossadmiral Karl Dönitz sent his U-boats to American waters in the winter of 1942, he 

tasked several with patrolling the GoM. Among these vessels was U-506 under the command of 

Kapitänleutnant Erich Würdemann. Würdemann and his crew were the second U-boat ordered to 

the GoM (Tent 2003). There were only four U-boats operating in the GoM in May 1942. Those 

four U-boats however, sank 41 ship,s equaling 220,000 tons of lost cargo. These sinkings were an 

all-time high (until June 1942) for U-boat operations anywhere in the world. On average, seventyfive merchant vessels operated in the GoM at any given time. This sinking rate equates to the 

average life span of a ship in the GoM in 1942, being less than two months (Sternhell and 

Thorndike 1946).

At 2200 hrs. on May 16, 1942, U-506 spotted a fully loaded tanker, Gulfoil, traveling on a course 

of 110 degrees in the GoM. Seizing the opportunity to inflict damage to allied shipping, U-506 

launched torpedoes from tubes two and three. It took only 34 seconds for the torpedoes to travel 

634 m before impacting the starboard side of Gulfoil. The first torpedo is reported to have struck 

amidships and the second torpedo struck the engine room. The mate on watch in Gulfoil’s

wheelhouse at the time of the attack reported the first torpedo struck near tank No. 4. And the 

second torpedo struck the engine room 15 seconds later, killing three men. The first impact caused 

the vessel to list 40 degrees before the second impact partially righted the vessel. The ship sank 

stern first with a heavy list so rapidly that the crew did not have time to launch the life boats. 

Gulfoil sank in approximately 2 minutes with only 19 of the 40 crewman surviving (Würdemann 

1942; Wiggins 1995; Browning 1996).

10.5.5.2 Field Investigations

10.5.5.2.1 Discovery and Exploration 

The site was first discovered in September 2005, when Diamond Offshore Drilling, Inc. contracted 

Oceaneering International, Inc. to conduct sonar and ROV video documentation of approximately 

670.6 m of 20-inch pipe lost from the Ocean Voyager oil rig during hurricane Katrina. During the 

investigation, sonar revealed a potential shipwreck. In October 2005, Fugro Chance Inc. 

conducted a geophysical survey of the area, which produced another image of the shipwreck. 

Fugro Chance notified the MMS and provided a data reproduction of the side-scan sonar image of 

the vessel. No further investigation was conducted until the first leg of the 2008 Lophelia II Study.
476

10.5.5.2.2 Lophelia II: Reefs, Rigs, and Wrecks 2008 Field Cruise

A reconnaissance survey was carried out on the site suspected to be Gulfoil on September 15, 2008

during the Lophelia II study using the Falcon SeaEye ROV launched from the NOAA Research 

Vessel Nancy Foster.

The ROV was in the water and nearing bottom, when a generator on the Nancy Foster broke down, 

sending the vessel adrift. Once propulsion was regained, the Nancy Foster was back on location 

and the ROV launched within an hour. Strong subsurface currents and low visibility, a result of 

Hurricane Ike, hampered operations and resulted in the loss of the microbial experiment intend to 

be placed on the wreck site. The ROV reached the wreck in approximately half an hour and began 

the reconnaissance survey. Despite conditions, the ROV successfully surveyed a portion of the 

wreck’s port side for an hour. Although the wreck was covered with colonies of Lophelia corals, 

it was positively identified by the word “Gulfoil” emblazoned on the stern. Continuing equipment 

issues and poor site conditions allowed only 48 m of the port hull to be investigated (deck level 

from the stern to just forward of the after cabin) before the dive was terminated when the ROV 

lost power.

10.5.5.2.3 C-Surveyor III 2009 AUV Survey 

Field investigations at the Gulfoil were not undertaken in 2009 as part of the Lophelia II study; 

however, C & C Technologies, Inc., conducedt an AUV survey of the shipwreck in May 2009.

This AUV investigation was part of an equipment upgrade test comparing the AUV’s 230 kHz 

dynamically focused and 410 kHz side-scan sonar systems on C&C’s C-Surveyor III AUV. During 

this survey, C-Surveyor III ran eight transects over Gulfoil at 75-m line spacing to image the main 

hull wreckage and associated debris fields. The sonar images revealed the vessel to be mostly 

intact with a debris trail extending approximately 230 m to the south and a separate debris field 

approximately 300 m west of the site (Figure 10-136). 
477

Figure 10-136. 2009 Side scan sonar mosaic of the Gulfoil site (C & C 

Technologies, Inc.).

10.5.5.2.4 Lophelia II: Reefs, Rigs, and Wrecks 2010 Field Cruise 

A second ROV investigation of Gulfoil occurred on October 27 and 28, 2010, from the NOAA 

Research Vessel Ronald H. Brown. The ROV Jason II from the Woods Hole Oceanographic 

Institution took high-definition video and photographs, as well as biological samples. The 2010 

investigation began at a debris field to the west of the wreck site. Investigations over a 1.5 hour 

period confirmed the debris field wreckage was related to the sunken tanker. The ROV then 

transited to the wreck site and approached the starboard side of Gulfoil’s bow. From this point, 

they worked their way around the bow and began moving aft along the port side. The ROV then 

returned to the bow and began investigating the wreck from top to bottom along the starboard side 

to the port stern. The ROV remained on site for approximately 19 hours conducting archaeological 

and biological investigations. 
478

10.5.5.3 Geographical Setting

Gulfoil is located in the northern GoM in the western portion of the Mississippi Canyon area. The 

site is south of the Mississippi River’s mouth along the northern edge of the Upper Mississippi 

Fan. The wreck site rests on the canyon’s western slope and is likely influenced by material 

flowing down the canyon. The seafloor in this region gently slopes toward the south, with local 

variations. 

10.5.5.4 Discussion of Archaeological findings

10.5.5.4.1 Physical Site

The following description is compiled from data collected during the 2008 and 2010 Lophelia II

field expeditions and the 2009 C&C AUV tests. Visibility at the site was approximately 10 m

during both ROV investigations. The Gulfoil lies upright on the seafloor with the bow down slope. 

The wreck is oriented with the bow pointing south-southwest and stern north-northeast. Water 

depth at the site is approximately 534 m BSL. The wreck has a relief of approximately 16.8 m

above the seabed. 

Three primary components characterize the Gulfoil site: the main hull with bow pointing southsouthwest, a debris trail extending 230 m south-southwestward from the hull, and separate debris 

field approximately 300 m to the west of the hull. The debris areas contain miscellaneous ship 

components. Debris in the western debris field includes items such as ventilator hoods, deck 

grating from the engine or boiler rooms, and unidentifiable debris. The builder’s specifications list 

the only areas on the ship to utilize removable deck grating as the engine and boiler rooms. 

Removable deck grating allows easy access to engine and boiler components for maintenance 

purposes. Figure 10-137 displays deck grating from the debris field with deck grating from the 

liberty ship Jeremiah O’Brian. The presence of the deck grating in the western debris field is 

significant because it correlates with the location the second torpedo struck the engine room.

Figure 10-137. Deck grating from Gulfoil (left) and deck grating from Jeremiah O’Brien 

(right) (Jason II ROV camera; William M. Briggs, 1012).
479

Overall, the site appears relatively intact. The ship is resting with a slight list to starboard. The 

superstructure is almost entirely obscured by abundant coral formations. These coral formations 

cover almost every part of the vessel that extends from the main deck into the water column. 

The ship’s bow displays a large hull buckle in the middle of the cutwater (Figure 10-138). This 

damage appears to be caused by the ship’s impact with the seafloor. The folding of steel plates 

and beams in what is one of the most structurally sound areas of a vessel may indicate the force 

with which the ship struck the seafloor or it could be evidence of a previously undocumented 

mishap in the ship’s life. The ship’s bow anchors are still in the stowed position with their chains 

leading to the intact windless. Portions of the masts and cargo booms lay on the main deck roughly 

pointing bow-to-stern next to their cargo winches. 

Figure 10-138. Buckle in bow of the Gulfoil.

Forward of the wheelhouse, in the oil fuel and dry cargo storage areas on the starboard side of the 

hull, is a large hole with an accompanying gash extending from just above the waterline to below 

the mud line and from just aft of the forecastle nearly to the wheel house (Figure 10-139). The 

hull plating in the area of the hole is bent inwards and the cargo hatches and some of the deck 

plating above this damage are bent upwards almost in half, indicating a violent explosion (
480

Figure 10-140). This damage contradicts historic accounts from the crews of Gulfoil and U-506 

identification of the first torpedo impact (Würdemann 1942; Wiggins 1995; and browning 1996). 

Figure 10-139. Forward hull damage in the Guloil (C&C Photo mosaic).
481

Figure 10-140. Deck plate/cargo hatches from the Gulfoil associated with hull damage.

The stack with ship’s whistle still attached is located on the seafloor adjacent to the forward 

structural damage (Figure 10-141). The stack was originally located on the stern of the vessel 

extending above the after cabin. Its presence on the seafloor near the bow of the ship indicates 

that the stack may have come loose as Gulfoil plunged stern-first through the water column. 

Figure 10-141. Gulfoil’s stack and ship’s whistle.
482

The wheelhouse is almost entirely covered in the deep-water coral Lophelia pertusa (Figure 

10-142). The architecture seems to be intact, with ladders still present on the weather decks. The 

hull in this area appears structurally sound with no sign of torpedo damage near starboard Tank 4,

where the first torpedo is reported to have struck. 

Figure 10-142. Wheelhouse coral growth on the Gulfoil.

The amidships area is relatively intact, with abundant coral growth covering the catwalk, main 

deck structures and entire after cabin. An ammunition box with shell casings for the ship’s 4-inch 

naval gun rests on the port side deck near the after cabin (Figure 10-143). 

Figure 10-143. Ammunition box with shell casings on the Gulfoil.
483

The location of where the second torpedo struck the starboard side is visible beneath the after cabin 

from the main deck to below the mud line (Figure 10-144). One of Gulfoil’s three Scotch boilers 

is visible through the after portion of the hole. This damage is consistent with historic reports that 

state the second torpedo struck the engine room causing the vessel to sink stern-first at a very rapid 

rate (Würdemann 1942; Wiggins 1995; Browning 1996). Interestingly, there is still glass present 

in the portholes just above this area. 

Figure 10-144. Hole from the second torpedo.

Visible on the fantail is the auxiliary steering helm which stands in its original position near the 

aft bulkhead of the after cabin with no coral growth and the ship’s defensive 4-inch gun, which is 

covered in coral (Figure 10-145). The vessel’s name is still visible across the stern in raised letters 

(Figure 10-146).
484

Figure 10-145. Gulfoil’s 4-inch gun with auxiliary steering on the left side of the photo.

Figure 10-146. Gulfoil’s transom with a portion of the name visible.
485

10.5.5.5 Site Formation and Distribution

The features observed during the investigation, combined with the historical record provide clues 

to understanding the Gulfoil site formation processes and a possible sinking scenario. The logs of 

U-506 state that the Gulfoil was on a heading of 110 degrees at the time of the attack. U-506 fired 

two torpedoes, which hit the tanker 15 seconds apart. Survivor accounts indicate that Gulfoil sank 

in approximately 2 minutes after the attack (Würdemann 1942; Wiggins 1995; Browning 1996). 

The tanker now sits on the seafloor on a heading of 193 degrees with a debris trail extending 230 

meters toward the south-southwest. 

In 2007, a Debris Distribution Model was developed based on data from deep-water World War 

II wreck sites as part of the Archaeological and Biological Analysis of World War II Shipwrecks 

in the Gulf of Mexico (OCS Study MMS 2007-015). The distribution formula was conceived as a 

preliminary first step in developing a predictive model for shipwreck site distribution in deepwater. As such, it was based on a small sample of World War II era ships that met with catastrophic 

ends. The Distribution Model provides a method to estimate the potential distance debris will 

spread out as a steel hull vessel sinks with regards to water depth (Church et al. 2009). The formula 

for that distribution is 20 percent of water depth plus the length of the hull and is listed below. 

Comparing the Gulfoil site with other wreck sites using the Deep Wrecks Debris Distribution 

Model shows that a vessel the size of Gulfoil at the site depth of 534 m BSL could have an artifact 

distribution of 231 m extending from the main hull of the wreckage. 

0.20wd + vl≥ site boundary

Where: wd = water depth

vl = vessel length

This estimate corresponds to the length of the debris trail associated with Gulfoil extending to the 

south-southwest of the main hull, but fails to account for the separate debris field to the west. It 

was initially hypothesized during the field investigation that these two debris fields represented 

the two separate torpedo impacts. Further examination of the geophysical data showed, however, 

that the center of the western debris field is over 300 m from the end of the debris trail. Based on 

available historical records, Gulfoil was traveling at 11 knots (11 knots equals 5.6589 m/second) 

when the torpedoes struck the ship. The torpedoes hit 15 seconds apart and at that speed, Gulfoil

could not have traveled more than 85 m (15 × 5.689) between the first and second torpedo strikes.

The assessment of data further shows that the near-parallel paths of both torpedoes would have 

been much closer together than 85 m. The first torpedo hit near the bridge and the second torpedo 

exploded in the engine room. The distance along the ship from the first to the second hit location 

is approximately 80 m apart. With the tanker moving forward at 11 knots and covering a distance 

of 85 m, the spatial separation between the two torpedoe’s parallel paths just prior to impact would 

have been only 5 m (Figure 10-147). The data shows, with a high degree of certainty, that the 

observed artifact scatter to the west of the main wreck site represents the location of both torpedo 

impacts on the Gulfoil.
486

Figure 10-147. Estimated attack scenario on Gulfoil based on torpedoes approaching perpendicular to the tanker. Red shows 

the first torpedo hit and blues shows the second.
487

Identification of the torpedo impact location to the west of the main wreckage raises two questions: 

How far could the tanker have theoretically traveled in two minutes after the torpedoes hit and will 

the theoretical calculations match what is found at the site? To answer these questions, the events 

following the second torpedo impact must be examined mathematically. The second torpedo 

struck the engine room, presumably stopping the engines at the time of the torpedo’s detonation. 

Historical and archaeological evidence indicate the Gulfoil sank-stern first within 2 minutes after 

the torpedo impacts. In order for this to occur, the Gulfoil must have slowed during that time span 

from 11 knots to a near stop before it plunged beneath the surface stern-first, but could it have 

traveled far enough in 2 minutes to account for the distance between the two debris fields? To 

determine this, standard acceleration (or in this case deceleration) formulas were used to 

mathematically calculate the rate of deceleration (represented as a negative number) and the 

distance travelled by Gulfoil.

The first step in this calculation was determining Gulfoil’srate of deceleration. This was calculated 

using the formula:

a = (Vf - Vi)/t

Where: a = acceleration in m/second (m/s)

Vf= Final Velocity in m/s

Vi= Initial Velocity in m/s

t = time in seconds 

Using a final velocity of 0 m/s, an initial velocity of 5.65884 m/s, and a time of 120 seconds, 

Gulfoil’s deceleration after the second torpedo impact would be −0.04716 m/s. With a known 

deceleration rate, the distance Gulfoil travelled before sinking was determined using the formula:

d = (Vf+Vi)t + (1/2)at2

Where: d = distance in m (m)

Vf= Final Velocity in m/s

Vi= Initial Velocity in m/s

t = time in seconds 

a = deceleration rate in m/s

Using the calculated deceleration (−0.04716 m/s) to solve the equation shows the Gulfoil would 

have covered a distance of approximately 340 m in the 2 minutes following the second torpedo 

impact. Additionally, the torpedo damage to the starboard side reportedly gave Gulfoil a starboard 

list and may have created additional drag. This additional drag would have possibly resulted in 

the vessel slowly turning to a southerly course. Applying a constant 3° estimated turn to starboard 

(south) for a distance of 340 m from the approximate torpedo impact location, places the Gulfoil

very near the southern end of the debris trail before sinking.2 As the Gulfoil sank, it plunged sternfirst in a north-northeast direction towards the seafloor, leaving a trail of debris in its wake (Figure 

10-148).

 

2 The product (340 m) was a calculated distance resulting solely from the data entered. The estimate of 3°, however, 

is an uncalculated adjustment to the ship’s course based on where the end of the debris trail starts, knowing that the 

ship did not likely continue on a heading of 110°.
488

Figure 10-148. Sonar mosaic image with estimated Gulfoil surface attack and sinking scenario 

(Sonar data courtesy of C & C Technologies, Inc.).

Therefore, the substantial distance between the two debris areas can be accounted for by the 

decelerated movement of Gulfoil during the 2 minutes following the U-boat attack. The distance 

covered also explains the initial miscalculation of the site size using the shipwreck distribution 

model formula, which could only account for the distribution of debris after the vessel left the 

surface sinking to the seafloor. The debris from the torpedo hits and debris trail from the hull are 

then taken as two sinking events for the purpose of modeling the distribution of debris. Initial 

debris fell from Gulfoil when the torpedoes struck the hull. The debris would spread out from that 

point leaving a scattered “shotgun” pattern of artifacts on the seafloor. The observed debris field 

west of Gulfoil is scattered approximately 82 m from the estimated center. That places the debris 
489

field well within the projected distribution estimate of 106 m using the Debris Distribution Model. 

When the vessel itself left the surface two minutes later, wreckage began trailing away from the 

tanker as air was forced out of the hull and hydrodynamic shear acted on the hull as it fell toward 

the seafloor. The debris trail and hull remains also fit into the distribution model as previously 

discussed. 

Combining the shipwreck Debris Distribution Model with estimated distance traveled based on 

deceleration and time following the torpedo attack proved invaluable in understanding the site 

formation processes at the Gulfoil. The ability to more accurately predict site distributions should 

also aid investigations of other shipwreck sites lost through catastrophic sinking events related to 

warfare or accident. If the necessary information is available, researchers will be able to better 

calculate projected search areas, determine the location of the initial sinking event, and better 

understand the site formation processes at work on deep-water wreck sites. 

10.5.5.6 Site Preservation

The Gulfoil is in a good state of preservation. The starboard (western) side of the wreck has 

extensive damage from torpedo impacts just forward of the central bridge area and near the stern. 

This damage does not appear to have destabilized the hull which appears to still be sound. Other 

than the visible torpedo damage, the wreck is mostly intact. Rusticles are visible on the anchors 

and hanging from hull plating around the damaged areas on the starboard side. The vessel’s 

superstructures and most of the other ship’s components extending into the water column are 

covered with extensive growths of coral, making accurate assessment of structural integrity nearly 

impossible. Currently no microbiological or corrosion test platforms are in place on the site. 

10.5.6 Gulfpenn Wreck Site

10.5.6.1 Historical Background of the Gulfpenn

In 1916, the Sun Shipbuilding Company was formed in Chester, Pennsylvania, as an affiliate to 

the Sun Oil Company to bolster tanker construction, which was in great demand because of World 

War I. After the war, the Sun Shipbuilding Company continued constructing tankers, including 

Agwihavre, later renamed Gulfpenn (Figure 10-149 and Figure 10-150). Agwihavre’s keel was 

laid on April 2, 1920, and was launched June 16, 1921 (Kavanagh et al. 2001). She was built for 

the Atlantic, Gulf, and West Indies Steamship Line of New York. The vessel was a screw steamer 

powered by a quadruple expansion engine, located in the aft portion of the vessel. She had a length 

of 480.6 ft (146.5 m), a beam of 65.6 ft (20 m), a 36.7 ft (11.2-m) depth of hold, and was 8,862 

gross tons. The tanker had a plain stem with forecastle head, elliptical stern, and two masts. The 

Gulf Oil Corporation of Philadelphia, Pennsylvania acquired the vessel in 1942. Ownership of 

Agwihavre was transferred to the Gulf Oil Corporation of Philadelphia, Pennsylvania, and the 

vessel was renamed Gulfpenn. On March 11, 1942, the Gulfpenn (Official Number 221244) was 

registered in the Port of Philadelphia, Pennsylvania under license to Arthur S. Hodges, as a 

coasting trade vessel (Gulfpenn 1921; and Gulfpenn 1942). 
490

Figure 10-149. Tanker Gulfpenn, photograph taken by the United States Coast Guard (Courtesy 

of Mariner’s Museum, Newport News, Virginia).

On February 28, 1942, Gulfpenn had its first exposure to U-boat activity when the crew received 

word that the unarmed oil tanker SS Oregon was attacked north of Cape Engano, Dominican 

Republic. Oregon was en route from Aruba to New York with a cargo of fuel oil when U-156

(Hartenstein), which was out of torpedoes, caught and sank the tanker with its deck guns. U-156

killed several of Oregon’s crew with machine-gun fire while they launched lifeboats. The 

following day, Gulfpenn rescued a group of survivors from Oregon (Hughes 2004; and Hocking 

1969: 528).

On May 13, 1942, the unarmed Gulfpenn was transporting 90,000 barrels of gasoline from Port 

Arthur, Texas, to Philadelphia, Pennsylvania. Gulfpenn was steaming about eight km ahead of 

another tanker, Gulfprince. At dawn Gulfprince was attacked by U-507. The first two torpedoes 

fired by U-507 were spotted by Gulfprince’s lookouts and successfully evaded. The third glanced 

off the tanker’s hull, but did not explode. The impact caused some damage, but both tankers 

escaped. Gulfprince sent a radio alert of the attack. Captain Harro Schacht of U-507 stated in his 

logs that it was useless to pursue the tanker on the surface because his deck guns were secured, it 

was getting light, and the area had been alerted to his presence (Schacht 1942; and SeaWaves 

2005).

At 1450 hours (CT) on May 13th, Gulfpenn’s luck ran out when she crossed paths with U-506. The 

tanker had been traveling at 11 to 12 knots and zigzagging in irregular patterns. They were running 

radio-silent with four lookouts on duty, one on the forecastle, one on the bridge, and two on the 

aft deck. The weather was clear with moderate seas and light winds. Visibility was good and one 

other ship could be seen approximately 8.8 km astern. The U-boat’s torpedo struck the engine 

room, destroying that section of the ship, immediately stopping the engines, and killing all of the 

personnel in the engine room. The tanker sank stern first, taking only five minutes to slip beneath 

the waves. Out of the 38 crewmen, 26 made it into lifeboats. Of these 26, one man died in a 

lifeboat while the Honduran vessel Telde rescued the remaining 25 survivors less than three hours 

after the attack (Burch 1942a). 
491

Figure 10-150. Architectural drawing of the tanker Agwihavre or “Gulfpenn,” by 

the Sun Shipbuilding Company, July 8, 1920 (From the Independence 

Seaport Museum collection).
492

10.5.6.2 Field Investigations

10.5.6.2.1 Discovery and Exploration

In 1994, the shipwreck, Gulfpenn, was discovered during a deepwater survey in Mississippi 

Canyon conducted for Shell International Exploration and Production Inc. John E. Chance and 

Associates using the Texas A&M University deep-tow system conducted the survey. The wreck 

was detected at the edge of the survey swath by side scan sonar, which was set at a range of 750 

m per channel (Figure 10-151). The large sonar target was within 13 km of the historical location 

of Gulfpenn. Marine archaeologist Laura Landry conducted an archaeological assessment of the 

survey and tentatively identified the shipwreck as Gulfpenn (Landry 1994).

Figure 10-151. Side scan sonar image of Gulfpenn from the Texas A&M University deep-tow 

system (Courtesy of Shell International Exploration and Production Inc.).

10.5.6.2.2 2004 DeepWrecks I ROV Investigation

The Gulfpenn shipwreck site was investigated in 2004 as part of the Deep Wrecks I Project. 

Investigations at the site were carried out using a Triton XL11 ROV from August 4 to 5 and August 

11 to 13, 2004 operated from the M/V HOS Dominator. As part of this project, the main hull and 

the surrounding area were investigated in detail. The examinations found the bow and forward 

sections of the main hull relatively intact, but with extensive deterioration of the superstructure. 

The aft section of the vessel was severely damaged and the stern had detached from the main hull. 

The missing stern section was found approximately 27 m northwest of the bow. Debris fields 

surround the main hull structure, with the largest field extending out nearly 161 m northwest of 

the remaining hull. The investigation concluded that the damage noted on the Gulfpenn was 

consistent with the historic accounts and surmised that, following the torpedo attack, the stern tore 

away from the main hull.
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The 2004 investigations also determined the site is in a moderate state of preservation. It is 

speculated that the aft section is deteriorating at a higher rate than the rest of the vessel as a result 

of the damaged sustained at the time of wrecking.

10.5.6.2.3 Lophelia II: Reefs, Rigs, and Wrecks 2008 Field Cruise

Archaeological investigations at the Gulfpenn were undertaken on September 8, 2008 from the 

R/V Nancy Foster. At 1041 hours, the ROV was put in the water to check the trim after the camera 

changes (The macro-camera was added to the ROV to replace the WesTech SDS3030). 

Unfortunately, during the trim check the ROV was pulled under Nancy Foster and the tether fouled 

between the ship’s rudder and port Z-drive. At 1105 hours, the cage was launched in an effort to 

pull the ROV down and unfoul the tether, which was successful and at 1110 hours, the tether cable 

was pulled free. The ROV was safely on the deck of Nancy Foster at 1220 hours. The ROV was 

back in the water at 1315 hours. Between 1315 and 1358 hours, the ROV descended to the 

Gulfpenn site. After a forty-three minute descent, the ROV was on the bottom. Progress across 

the seafloor was slow, because of strong current and poor visibility. At 1439 hours, the team began 

ROV investigations of the suspected stern section. They observed what appears to be the vessel’s 

rear flagpole, still standing after more than a half century on the seafloor. At 1500 hours, the ROV 

was moved to the cage for a brief inspection. At 1505, the ROV headed to the wreck’s main 

section. The ROV maneuvered to inspect the abundant coral colonies on the bow. Significant 

amounts of coral, which had broken off and fallen from the hull above, were observed on the 

seafloor. From 1520 to 1600 hours, the team inspected the Gulfpenn’s leeward (port) side where 

working conditions were more favorable. At the forward edge of the aft deckhouse, a large 

Lophelia colony, once attached to the lifeboat davit was found in pieces scattered across the ship’s 

hull and a the surrounding seafloor. Following the port side investigations, the ROV moved to the 

starboard side to inspect a microbial platform placed in 2004, but strong currents hampered ROV 

operations. Between 1757 and 1803 hours a temperature logger was placed on the starboard bow. 

At 1805 hours, the main LED light on the ROV malfunctioned and the vehicle was recovered 

without collecting biological samples.

During the ROV recovery, the tether was fouled in the port Z-drive and severed. The damaged 

tether forced the termination of further investigations on the Gulfpenn. 

10.5.6.2.4 Lophelia II: Reefs, Rigs, and Wrecks 2009 Field Cruise

The 2009 investigation of the Gulfpenn took place on September 10, 2009. This investigation 

focused on documenting the Lophelia colonies and biologic activity on the wreck, so 

archaeological investigations were limited. For a complete description of the 2009 investigations 

at Gulfpenn, please refer to the biological section of this report. The limited archaeological 

investigations at the site focused on the superstructure near the middle of the wreck and on the 

previously placed microbiological platform. Jason II was used to image areas of the bridge and to 

photograph the engine order telegraph that was used to communicate between the bridge and the 

engine room. Near the aft deckhouse, the microbial experiment deployed in 2004 was relocated. It 

had fallen over on its side, so the team picked it up with Jason II and stood it against one of the 

structures on the deck. An additional long-term microbiological experiment was set on the 
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Gulfpenn’s port bow, along with a short-term experiment. The short-term experiment was 

unfortunately not recovered at the end of the dive. At 11:37, the investigations on the Gulfpenn

were finished and Jason II returned to the surface. 

10.5.6.3 Geographical Setting

The Gulfpenn wrecksite area is located in the central portion of the Mississippi Canyon area of the 

northern GoM. The site is south of the mouth of the Mississippi River along the Upper Mississippi 

Fan’s northern edge. The Mississippi Fan is a bow-shaped fan made up of several fan-lobes and 

separated into three major regions: Upper, Middle, and Lower. The Mississippi Canyon is the 

conduit for the source material that comprises the Mississippi Fan (Bouma et al. 1985). The wreck 

site rests on the canyon’s eastern slope and is likely influenced by the material flowing down the 

canyon. The seafloor in this area gently slopes at approximately three degrees toward the south 

with local variations in the seafloor slope. The seafloor trend at the wreck site is to the southsouthwest (Figure 10-152). This area’s sedimentation rate is relatively low in this area, 

approximately 2.13 mm per year.

10.5.6.4 Discussion of Archaeological Finding

10.5.6.4.1 Physical Site

The following description of the wreck site is compiled from data collected during the 2004 

DeepWrecks field expedition and the 2008 and 2009 Lophelia II field seasons.
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Figure 10-152. Site Map of the Gulfpenn Wreck Site base on ROV investigations.

The wreck is oriented with the bow pointing north-northwest and stern to south-southeast (Figure 

4‒146). Water depths range from approximately 553 m at the bow to 555 m at the stern. The 

vessel’s bow extends into the water column more than the stern. The deck of the forecastle stands 
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about 18 m above the ambient seafloor as opposed to the aft deckhouse, which rises approximately 

5.5 m above the ambient seafloor. 

The bow and forward section are relatively intact (Figure 10-153). The catwalk and piping are 

extant from the forecastle to the bridge structure. Coral covers the catwalk and railing, particularly 

along the starboard side of the vessel, obscuring much of the structural detail. The foremast has 

separated from the deck and fallen forward. The foot of the mast lies on the deck and the midportion lies across the forecastle near the end of the catwalk. The mast’s upper parts appear to 

have broken away and are gone. Figure 10-154 shows a site map of the shipwreck’s main structure.

Figure 10-153. Bow of the Gulfpenn.
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Figure 10-154. Site drawing of Gulfpenn’s main structure (Drawn by Robert A. Church).
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The superstructure’s upper works show a considerable deterioration. The pilothouse is gone and 

the bridge’s deck is disintegrating. The remaining superstructure, mainly on the port side, is 

collapsing with sections of metal plating partially suspended from the vessel. The ship’s telegraph 

has fallen over and spans part of the metal framework of the bridge (Figure 10-155). The 

superstructure’s starboard side is almost entirely obscured by prolific coral formations. 

Figure 10-155. Top of Gulfpenn’s superstructure showing the bridge 

telegraph lying across the exposed deck frame supports.

Extensive damage is also present aft of the vessel’s main superstructure. Although the catwalk 

and piping from the main structure to the aft deckhouse are intact, the hull amidships has partially 

collapsed. Sections of the railing and gunwales are lying nearly flat against the deck and the deck 

is buckled inward in places. There are two hull breaches on the starboard side. The first is 

approximately 16.7 m aft of the main superstructure and the second is approximately 25.5 m

further aft than the first rupture (Figure 10-156). On deck, the starboard stanchion (small mast) 

remains upright approximately 8.3 m aft of the main superstructure, but the port stanchion has 

fallen forward with the upper part extending beyond the side of the ship. The main mast has fallen 

forward and lies on the deck (Figure 10-157). Corals cover the catwalk along this section of the 

wreck.
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Figure 10-156. Breach in the Gulfpenn’s hull along the vessel’s starboard side.

Figure 10-157. Foot of the Gulfpenn’s main mast lying on the deck.

Gulfpenn’s aft portion exhibits the most severe damage. The deck of the aft deckhouse is 

deteriorating and has partially collapsed inward exposing the interior. The main smokestack is 

gone, leaving behind a gaping hole where it once stood. Two vent pipes were originally located 

directly forward of the main stack. The starboard vent pipe still stands, albeit missing a vent hood. 

The port vent has been destroyed with only fragments visible where it should be. A skylight or air 

vent at the deckhouse’s center is relatively intact. Roughly nine m aft of the skylight the hull ends 

abruptly in a contortion of mangled metal plating. Almost 11 m of the stern has been ripped away. 
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Only partial remains of the aft helm controls, used for docking, are visible forward of this severely 

damaged area (Figure 10-158). Coral partly covers the wreck’s aft section, and is more prevalent 

on the vessel’s starboard side. Coral growth obscures much of the vessel’s structural details on 

the starboard side, making them difficult to distinguish. 

Figure 10-158. Remains of the Gulfpenn’s docking helm control on the aft deckhouse.

An extensive artifact scatter surrounds the wreck site. The main debris zone extends nearly 161 

m northwest from the vessel. An area of light debris extends 130 m southwest of the main hull. 

Smaller debris extends 65 m to 70 m east and west of the primary wreckage. A large section of 

the ship, which appears to be the stern’s missing section (Figure 10-159), lies within the main 

debris field 27 m northwest of the bow. Other material within this dense debris field includes vent 

hoods and pipe (Figure 10-160(a,b)), railing, twisted metal, and a lifeboat (Figure 4‒155). The 

vent shown in Figure 10-160a lies within a few meters of the suspected stern section. The vent 

hood shown in Figure 10-160b lies 133.6 m northwest of the bow. The lifeboat shown in Figure 

10-161 is 73 m northwest of the bow. The missing stack lies 25 m east of the aft deckhouse’s 

starboard side, nearly perpendicular to its original deck location (Figure 10-162). The funnel is 

almost completely flattened, with the top pointing away from the vessel. The ladder and steam 

whistle running up the stack’s forward edge are still intact.
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Figure 10-159. Possible section of the Gulfpenn’s detached stern.

Figure 10-160. a) Vent hood (left) lying near the separated stern section. b) Vent hood (right)

lying near the northern extent of the Gulfpenn’s debris field.
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Figure 10-161. Lifeboat from Gulfpenn in the debris field (Photo mosaic).

Figure 10-162. Gulfpenn’s main stack, lying to the vessel’s starboard side (Photo mosaic).

Gulfpenn’s stern damage is consistent with the historical accounts of the U-boat attack. The 

evidence suggests the torpedo attack ripped the stern from the main hull. As the disarticulated 

stern plunged to the seafloor spilling debris, the remainder of Gulfpenn’s hull sank near the after 

most section. As the hull planed downward it, crossed over the fragmented stern section and debris 

trail impacting the seafloor behind it. Gulfpenn’s main hull impacted the seafloor aft section first, 

collapsing the torpedo-damaged aft hull and leaving the bow extending proud off the seafloor. The 

masts’ standing rigging possibly parted as a result of explosions during the attack. Drag 

encountered through the water column as the vessel sank likely caused forward stress on the masts 

before the ship impacted the seafloor. The fore and aft masts have both fallen forward, at a similar 

angle of four to nine degrees to port with their foot lying near the base, indicating they likely 

collapsed as a result of uniform stress experienced on impact. It is possible that both masts fell 

before impact, but if the bolts holding the base had already given way, the masts would likely have 

slid aft on impact, which is not indicated from their present orientation.
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10.5.6.5 Site Preservation

The wreck site is in a moderate state of preservation. The bow section is in good condition, but 

the aft section has considerable damage from the wrecking event. Some decking is still intact, but 

is rapidly deteriorating. The severe damage to the hull’s aft section indicates the aft section likely 

will collapse before the bow and main superstructure.

10.5.7 Deustche Kreigsmarine (DKM) U-166 Site

U-166 site was not initially one of the wreck sites scheduled for investigation during the Lophelia

II; Rigs, Reefs, and Wrecks project. However, the 2010 field investigations of nearby biological 

sites provided an unanticipated opportunity to visit the wreck. Due to project time constraints, no 

detailed archaeological documentation was undertaken. Operations on the site during the 2010 

visit were limited to brief visual examination of the two hull sections and the long-term 

microbiological experiment deployed during the 2003 investigations, sediment core sampling, and 

biologic sampling. The historical background and discussion of previous work are provided here 

for reference. For in-depth discussions of this site, see “Archaeological and biological analysis of 

World War II shipwrecks in the GoM: Artificial reef effect in deep water” (OCS Study MMS 

2007-015).

10.5.7.1 Historical Background of DKM U-166

During the early months of 1942, the war seemed far away to most Americans, but in reality an 

ominous threat lurked in the waters off the Eastern and Gulf Coasts. America’s entry into World 

War II, provided Hitler the opportunity to extend U-boat attacks to America’s shores just as the 

Kaiser had in World War I. This time, however, Hitler’s U-boats would not limit attacks to 

America's East Coast. They would strike deeply into America's backyard, the GoM. In just over 

a year's time, beginning in May 1942, twenty-four German U-boats entered the GoM. Seventeen 

of these U-boats, including U-166, sank fifty-six merchant ships and damaged several others 

(Wiggins, 1995). 

U-166 (Figure 10-163 and Figure 10-164) was built at the Seebeck Shipyard in Bremen, Germany 

between December 6, 1940 and March 23, 1942 (Morgan and Christ 2003). U-166 was 76.8 m

long, had a beam of 6.8 m, and a draft of 4.7 m. It was one of 54 type IXC U-boats constructed 

by Germany during World War II. The IXCs were long-range fast-attack submarines. They were 

built to carry the war to foreign shores using two supercharged nine-cylinder MAN diesel engines 

that generated 2,200 horsepower each, and 208 tons of fuel. On the surface, a IXC could make 

18.3 knots, and 7.3 knots submerged. Larger diesel bunkers than previous designs allowed the 

IXCs a surface range of 11,000 nautical miles at 12 knots, and a submerged range of 63 nautical 

miles at 4 knots. Like most type IXs, U-166 had a full double hull with the outer hull extended 

nearly down to the keel (Miller 2000; and Rössler 2001). According to Rössler (2001), IXCs had 

a pressure hull composed of 10 sections with each section constructed of 4 to 6 steel plates welded 

on circular frames to form short cylinders. The plates had a thickness of 18.5 mm everywhere on 

the hull, except the conning tower where the plate thickness was increased to 22 mm (Rössler 

2001). The deck was wide and flat leaving room for ten torpedoes stored in pressure-tight 

containers. A IXC U-boat typically carried a complement of at least four officers and forty-four 

crew during wartime (Blair 2000; and Miller 2000). The class IXs were based on earlier Type IA 
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U-boats but had substantial improvements to engines, fuel capacity, and armament. The Type IXs 

and its short-range counterpart, the Type VII, formed the backbone of the German U-boat fleet 

(Miller 2000).

Figure 10-163. U-166 at sea in early 1942 (Kuhlmann Collection courtesy of the PAST 

Foundation and the National D-day Museum).

Figure 10-164. Schematic of a Type IXC U-boat (Courtesy of National Park Service and PAST 

Foundation).

U-166 was armed with twenty-two torpedoes that could be fired through four forward or two aft 

tubes. For surface actions, a 105-millimeter deck gun was mounted forward of the conning tower. 

Other armaments included a 20-millimeter machine-gun mounted on the single wintergarten and 

a 37-millimeter anti-aircraft gun on the aft deck for defense against aircraft or surface vessels. 
505

According to Miller (2000), later IXCs were constructed with an extended wintergarten for 

mounting additional anti-aircraft weaponry.

U-166 was constructed under the auspices of the man who eventually commanded her, 

Oberleutnantzur See Hans-GüntherKuhlmann (Figure 10-165). Kuhlmann, who was born in 

Cologne in 1913, served in the German Merchant Marine until joining the Kriegsmarine in January 

1937. At the start of the war in 1939, he served as the No. 2 Torpedo Officer on the German heavy 

cruiser Blücher until January 1940 when he transferred to the U-boat arm. Kuhlmann was assigned 

to U-37 as a third watch officer and over the next 13 months, he rose to the rank of first watch 

officer before leaving the boat for U-boat commander training. After successfully completing the 

commander’s course Kuhlmann was assigned to the 24th U-boat Flotilla and in March 1941 was 

given command of the training boat, U-7. In July 1941, he took command of the U-580, remaining 

on that boat until it was lost off Norway during a training exercise. Kuhlmann survived and took 

command of U-166 in March 1942. He then took his new boat and crew for a sixty-nine day 

shakedown cruise (Busch and Röll 1999). It would be one of only two cruises made by the U-166

(Morgan and Christ 2003).

Kuhlmann brought U-166 back into port on May 31, 1942. Seventeen days later U-166 left port 

on its first war cruise. The destination was the GoM. There Kuhlmann and his crew would mine 

enemy ports and attack allied shipping. Three days into the voyage, the crew of the new U-boat 

barely escaped a night attack by allied aircraft. The remainder of the crossing was uneventful and 

U-166 and her crew entered the Caribbean in mid-July. Kuhlmann and his crew did not claim a 

victory for several days after reaching the Caribbean. Then on July 13, 1942, they sank the 84-ton 

schooner Carmen. This success was followed in relatively quick succession by sinking of the 

2,309-ton freighter Oneida, and the 16-ton trawler Gertrude. Finding only small vessels in this 

area, Kuhlmann continued towards the GoM and the area off the mouth of the Mississippi River 

(Morgan and Christ 2003).

Figure 10-165. Oberleutnantzur See Hans-Günther

Kuhlmann (Kuhlmann Collection courtesy of the 

PAST Foundation and the National D-day Museum).
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U-166 entered the GoM in mid-July 1942 and proceeded to lay mines off the southwest pass of 

the Mississippi River (Morgan and Christ 2003). On July 27, 1942, Kuhlmann radioed German 

Naval Command reporting completion of mine-laying activities and that he was proceeding to hunt 

shipping (War Diary 1942: 36,53,92). It would be the final message from U-166.

While U-166 sailed to its assigned operation area, the passenger freighter Robert E. Lee left Portof-Spain, Trinidad bound for New Orleans, Louisiana on July 20, 1942 carrying 270 passengers, 

six merchant marine officers, and 131 general crewmembers. Robert E. Lee transited the 

Caribbean with a heavily escorted convoy, but during the morning hours of July 29, it 

rendezvoused with United States Navy Patrol Craft 566 (Figure 10-166) near Key West, Florida. 

Figure 10-166. An undated photograph of PC-566 (Courtesy of Mariner’s Museum).

Built in Houston, Texas, PC-566 was a 461 class patrol craft. It was 178 ft (54.3 m) long, had a 

23-foot (7 meter) beam, and could cruise at 20 knots. Constructed to defeat the enemy submarine 

threat, PC-566 was heavily armed with deck guns, rockets, and depth charges. Escorting Robert 

E. Lee was the naval vessel’s first mission and Lt. Commander Herbert C. Claudius’ first 

command. Under orders from the Commander of the Gulf Sea Frontier, PC-566 was to escort 

Robert E. Lee to Tampa, Florida where the steamer would re-provision (Charlton 2003; Henderson 

1942; and USS PC-566 1942).

U-166 prowled shipping lanes near the Mississippi River mouth at the same time Robert E. Lee

and PC-566 arrived at Egmont Key Light, Tampa Bay, on July 29, 1942 around 2145 hrs. When 

no pilots were available, the steamer used Morse code and signal lights to communicate with PC566. Robert E. Lee stated they would proceed to New Orleans rather than wait. At 2325 hrs, PC566 broke radio silence to notify the Commander of the Gulf Sea Frontier that Robert E. Lee was 
507

continuing to New Orleans and to request orders. PC-566 was ordered to escort Robert E. Lee and 

the two vessels were immediately underway (Church et al 2002; Henderson 1942; and USS PC566 1942).

Robert E. Lee and PC-566 transited across the Gulf through the night and into the next day,

drawing closer to U-166. July 30 was a clear, calm day. PC-566 was running half-mile ahead and 

to port of Robert E. Lee. The freighter and her naval escort were approximately 45 nautical miles 

southeast of the Southwest Pass of the Mississippi River when U-166 spotted the freighter. At 

1637 hrs, U-166 fired a torpedo at the freighter’s starboard side. Passengers and crew on Robert 

E. Lee noticed an elongated shape 150 m to starboard (Henderson 1942). The single torpedo fired 

by U-166 struck Robert E. Lee's starboard side. The resulting explosion tore through C and B 

decks destroying the engines. Lookouts aboard PC-566 spotted the U-boat’s periscope and the 

patrol craft moved to attack.

PC-566’s radio operator had been transmitting their estimated arrival time to the Port Director of 

New Orleans when U-166 attacked. The transmission was cancelled and an SOS for Robert E. 

Lee sent instead. Six lifeboats and sixteen life rafts were launched from Robert E. Lee as 

passengers and crew frantically abandoned ship. Robert E. Lee’s bow rose out of the water until 

it reached a precariously steep angle, and the vessel suddenly plunged to the bottom. Robert E. 

Lee sank between six and ten minutes after the torpedo attack according to survivors and naval 

witnesses. The disaster resulted in the deaths of ten crewmembers and 15 passengers (Church et 

al 2002; Henderson 1942; USS PC-566 1942; and Winnier 2003). As the freighter sank, Kuhlmann 

made a fatal error. Evidently not noticing the patrol craft, he kept U-166 at periscope depth, and 

PC-566 moved in for the kill. 

U-166’s first indication that they were under attack was probably when PC-566’s active sonar rang 

against the U-boat’s hull from just 230 m away. The U-boat immediately submerged, but PC-566

maintained the contact for another 120 m. Once PC-566 lost contact, it returned to the point where 

U-166 was last detected and a depth charge pattern of five charges was laid with settings for 76.2 

m (250 ft), 45.7 m (150 ft), and 30.5 m (100 ft). Following the first set of depth charges, PC-566

reversed course for 1000 m to re-establish sonar contact. At that time Captain Claudius noted 

Robert E. Lee was gone, and only lifeboats and rafts remained where the vessel had once been. 

PC-566 again detected U-166 with sonar only 550 m away. The contact was maintained as PC566 closed to within 350 m, and dropped a second pattern of five depth charges. Soon the first 

airplane from New Orleans arrived on the scene and Claudius instructed the pilot to perform an 

aerial search for the U-boat. Commander Claudius circled the area cautiously, using PC-566’s 

sonar to search for the U-boat. When the second plane arrived Claudius speculated the U-boat was 

either sunk or disabled and it was safe to begin rescue operations. While conducting the sonar 

search, PC-566’s crew noted a large oil sick on the surface. The brownish-gray slick was 60 m in 

diameter, and smelled of diesel oil. No other debris floated to the surface, but Claudius believed 

the U-boat was either sunk by the attack, or was “so mortally wounded that she would never return 

to her base” (USS PC-566 1942). 

Aside from the fatal torpedo that sank Robert E. Lee, the only evidence of U-166’s presence on 

July 30, 1942 was the periscope that had been spotted and the oil slick that appeared after PC-566

dropped its second set of depth charges. The submarine, believed by Naval Command to be only 
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slightly damaged by PC-566 during its attack, would turn out to have been sunk during the battle, 

but the location of the only U-boat lost in the GoM during World War II would not be identified 

for half a century.

Two days after the attack on Robert E. Lee, two U.S. Coast Guardsmen, Pilot Henry White and 

Radio Operator George Boggs, were patrolling in a J4F amphibious aircraft roughly 160 km south 

of Houma, Louisiana, when they spotted a U-boat on the surface. As the U-boat crash-dived 

towards deeper water, White and Boggs attacked with their only weapon, a single depth charge. 

White and Boggs reported the depth charge exploded near the submarine and an oil slick appeared 

on the surface. When they returned to base, they were informed the incident was classified. White 

and Boggs were later told they destroyed U-166 and were decorated for their actions.

For the next 59 years, history recorded U-166 sank 160 km south of Houma, Louisiana by two 

U.S. Coast Guard Aviators, Pilot Henry White and Radio Operator George Boggs on August 1, 

1942. Despite numerous regional oil and gas surveys and expeditions seeking U-166, the sub was 

not found until 1986. Then it remained incorrectly identified until 2001. U-166’s location near 

Robert E. Lee proves PC-566 destroyed U-166 on July 30, 1942. Historical records regarding Uboat actions in the GoM indicate White and Boggs attacked U-171. Although White and Boggs 

did not sink U-171, they did drive it from the coast and temporarily prevent it from sinking Allied 

vessels. Unfortunately, the commanding officer of PC-566 H. G. Claudius died in 1981 before 

learning that his attack on the U-boat that day in July 1942 had succeeded. Most of the surviving 

members of PC-566 have been informed of the discovery and history has been corrected.

10.5.7.2 Field Investigations

10.5.7.2.1 Discovery and Exploration

In 1986, Shell Offshore, Inc. was exploring the deep waters of the Mississippi Canyon area in the 

GoM for potential oil and gas prospects. Shell contracted John E. Chance and Associates to 

conduct a survey of the region using a 4075 EDO deep-tow system. During the survey, they 

detected two shipwrecks. The only shipwrecks that the MMS listed in the vicinity were two World 

War II casualties, Robert E. Lee and Alcoa Puritan. At the time, no archaeological assessments 

were required in deepwater lease blocks and it was not until 1994 that an archaeologist reviewed 

the data and prepared an assessment. Given the information at the time, it was realistic to assume 

Robert E. Lee and Alcoa Puritan had been found. No further investigations were undertaken 

because of the time and expense involved in conducting deep-tow surveys.

10.5.7.2.2 2001 Autonomous Underwater Vehicle (AUV) Survey

In January 2001, C&C conducted a survey for BP and Shell International in the Mississippi 

Canyon area near Robert E. Lee’s reported location. C&C performed the survey utilizing CSurveyor I, its new AUV, a completely untethered survey platform. During this survey, a large 

wreck was detected near the edge of the survey swath. C&C marine archaeologists Robert Church 

and Daniel Warren verified with the MMS that this was Robert E. Lee. Alcoa Puritan’s reported 

proximity to Robert E. Lee, prompted BP and Shell to agree that additional survey investigation 

with the AUV be conducted to locate any wreckage in relation to the proposed pipeline route. 
509

In March 2001, the additional survey work was completed. C&C archaeologists reviewed the data 

and noted Robert E. Lee’s wreckage and a new area of wreckage, less than a mile to the east, where 

the 1986 survey had placed the wreck of Alcoa Puritan. During analysis, it became apparent that 

the wreckage thought to be Alcoa Puritan was inconsistent with that size freighter. The wreckage, 

however, matched the dimensions of a Type IXC German U-boat (76.8 m in length and 6.7 m

wide), the same class as U-166.

Based on the geophysical evidence, a new hypothesis was developed to explain why U-166 was 

225.3 km east of its recorded position. The hypothesis proposed that U-166 was destroyed on July 

30, 1942, by Patrol Craft 566's depth charge attack, and that Coast Guard aviators White and Boggs 

bombed a different submarine that escaped. An examination of U-171’s reconstructed logs, the 

only other U-boat in the area at the time, lends credence to this hypothesis. These logs stated that 

U-171, around early August 1942, while off the Louisiana coast, was bombed by a "flying boat" 

(a good description of an amphibious aircraft) but sustained no damage. The attack's exact date 

could not be determined since the original logbooks were lost when U-171 was destroyed by a 

mine in the Bay of Biscay when returning from its GoM patrol.

The hypothesis that the second area of wreckage could be U-166 led BP and Shell to sponsor sitespecific investigations of the suspected U-166 and Robert E. Lee sites using the C-Surveyor I AUV. 

The results of this data (Figure 10-167) provided additional support to the U-166 hypothesis and 

stressed the need for verifying the wreck's identity through visual inspection.

Figure 10-167. High-resolution side scan sonar image of U-166, 2001 (Courtesy of BP, 

Shell, and the National D-Day Museum).
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Between May 31 and June 1, 2001, a research team comprised of representatives from BP, Shell, 

C&C, and the MMS traveled to the Mississippi Canyon Area to determine if the German U-boat, 

U-166 had been located. The research team used Gary Chouest, an anchor-handling vessel under 

contract to Shell and equipped with an Oceaneering Millennium VI ROV. 

The first glimpse of the vessel was the unmistakable conning tower of a German U-boat. The 105-

mm deck gun, 37-mm, and 20-mm antiaircraft guns were clearly visible. Post-field analysis and 

research revealed that each feature matched that of U-166.

Three distinct areas of wreckage were noted during the 2001 investigations of the U-166 wreck 

site: the stern, the bow, and a debris field. The site is oriented roughly north to south (Figure 

10-168). The stern remains are located near the site’s eastern limits and consist of an 

approximately 55-meter hull section including the deck guns and conning tower. The bow remains 

are located near the site’s western extent approximately 140 m west of the stern section. The bow 

section consists of approximately a 20-meter hull section extending from the prow aft to just past 

the forward torpedo hatch. Debris is scattered throughout the site, but the main scatter is between 

the bow and stern sections. The debris consists of various materials dislodged or ripped from the 

U-boat as it plunged to the seafloor.

Figure 10-168. Bathymetric data collected in 2001 showing the U-166 wreck site (Courtesy of 

BP, Shell, and the National D-day Museum).
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The investigation of the bow section provided a revealing look at a possible cause of the U-boat's

demise. A large indentation in the deck may be the result of a depth charge explosion. Just aft of 

this feature, the bow was torn from the rest of the hull and the serrated metal flares outward as if 

caused by an internal explosion. It is possible that a depth charge exploded very near the deck, 

ruptured the pressure hull, which in turn caused an internal explosion. It was speculated that salt 

water rushing into the battery room, which is located in this area of the U-boat, could have caused 

the batteries to explode. 

The expedition successfully identified the long-sought-after U-boat and its last victim. 

Unfortunately, only cursory wreck site examinations were carried out because of the ROV’s 

limited availability and capabilities. Time constraints with the ROV allowed only approximately

4 hours of investigation time at the wreck.

10.5.7.2.3 2003 C & C Technologies, Inc./NOAA OE Site Investigations

In October 2003, C&C Technologies, Inc., in conjunction with the NOAA Office of Ocean 

Exploration, Droycon Bioconcepts, Inc., and the PAST Foundation conducted a more thorough 

investigation of U-166 (Warren et al. 2004; and Church et al. 2004). The project’s purpose was to 

document in detail the U-166 wreck site. Over five days in October 2003, archaeologists and other 

scientists successfully recorded U-166’s remains.

To conduct the fieldwork, scientists used Sonsub's Innovator Class ROV from NOAA’s Research 

Vessel Ronald H. Brown. The ROV surveyed the wreck site following a pre-determined survey 

grid. The grid consisted of sixty-three lines oriented north-to-south and spaced 4.57 m apart to 

provide overlapping coverage. During the survey, the ROV flew between 1.83 and 4.57 m above 

the seafloor to minimize the chance of missing wreck pieces.

During the 2003 mapping project, 307 artifacts, and/or groups of artifacts were documented at the 

U-166 site. Over 50 hours of high-resolution digital video and approximately 1,800 digital still 

images were taken. No artifact materials were recovered because of the wreck’s status as an 

international war grave.

In addition to the archaeological investigations, the microbiological communities (rusticles) 

growing on U-166 were documented. Assessment of the rusticles at the U-166 site was 

accomplished with the placement of long and short-term experiments, and rusticle sampling from 

different wreck sections. Short-term experiments, called BARTS and etch tests, were placed on 

the wreck site at various locations and left in place for approximately 48 hours. The experiments

helped biologists determine the types and level of bacterial activity present at the wreck site. The 

long-term experiments utilized test platforms containing a variety of materials such as wood, iron, 

and aluminum. The long-term experiments were left on the wreck and checked during the 2004 

site visit (Figure 10-169).
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Figure 10-169. Microbiological experiments with BARTS and etch tests (left) and test platforms 

(right).

10.5.7.2.4 2004 Deepwrecks I Site Investigation

The 2004 Deepwrecks I archaeological investigations undertaken at U-166 continued the 2003 

fieldwork. The site’s southern extent was not established during 2003, and the 2004 work focused 

on locating this boundary. During the 2004 project, the science team surveyed seven additional 

lines south of where the 2003 investigations ended. The lines were approximately 330 m long, 

spaced 20 m apart, and covered an area approximately 100 m wide. The survey was terminated 

when the investigation of two successive lines found no further artifacts. 

The seafloor covered by the 2004 survey is relatively flat and composed of the same sediment 

found throughout the U-166 wreck site. The 2004 investigations located twenty-three additional 

artifacts associated with the wreck site. These were mainly hull fragments, most with more 

extensive impact craters than those to the north. Other artifacts documented during this field 

season included possible clothing. 

10.5.7.2.5 Lophelia II: Reefs, Rigs, and Wrecks 2010 Field Cruise 

In November 2010 the wreck of the German U-boat, U-166 was visited as part of the Lophelia II 

2010 field investigations. Over a 2.5 hour period on November 3, 2010 visual investigations of 

the stern and bow hull sections, core sampling, and biological sampling were undertaken using the 

Jason II ROV from on board the NOAA Research Vessel Ronald H. Brown. The examination of 

the U-166 began with photo documentation of the stern hull remains. Starting from the forward deck, 

the Jason II ROV was flown down the starboard side to the stern of the wreck as video and still 

imagery were acquired of the deck areas, conning tower, and guns. Once at the stern, Jason II’s 

course was reversed and the ROV headed back to the area of the conning tower. At the after side of 

the conning tower, the long-term microbiological experiment platform deployed during the 2003 

investigation was relocated and visually documented (Figure 10-170). Once examination of the test 

platform was completed, a single biological sample was acquired from the starboard after rail 

followed by the recovery of a single core sample at the stern. After collecting the core sample, Jason

II, transited to the bow section of the U-166, approximately 140 m to the west of the stern. Once at 
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the bow section, a 360 visual survey of the bow was conducted, including the relocation and visual 

inspection of the long-term microbiological experiment platform placed on the bow in 2003. Before 

leaving the bow section, a single core sample was taken just forward of the prow. Following the 

recovery of the core sample, Jason II began a transit to the nearby wreck of the Robert E. Lee. During 

the transit, an electrical problem forced the termination of the dive and the recovery of the ROV. 

Cruise time constraints prevented an additional ROV dive.

Figure 10-170. Images of the long term microbiological experiments on the U-166's stern (left) 

and bow (right) taken during the Lophelia II 2010 field cruise.

10.6 CONCLUSIONS

The historic shipwreck component of the Lophelia II: Rigs, Reefs, and Wrecks Study investigated 

six shipwreck sites in detail and visited one additional shipwreck site to monitor experiment 

platforms placed during previous investigations. Of the six primary vessels in this study, two are 

World War II era vessels (Gulfoil and Gulfpenn) and four are wooden shipwrecks of unknown date 

and identity. During the project’s three consecutive field seasons, details of these six sites were 

recorded using in situ documentation methods. From this data, the identities of the two World 

War II era vessels were reconfirmed. Study of the four wooden shipwrecks provided insights into 

their construction styles, when they were likely built, and when they may have been lost. However, 

despite extensive historical research, the identities of these four vessels remain a mystery. The 

data acquired using in situ documentation methods did not contain details specific enough to 

associate any of the study wrecks with any one candidate out of the hundreds of sailing vessels 

lost in the GoM in the nineteenth century. Conclusions regarding each of the six primary study 

wreck sites, their eligibility to the National Register of Historic Places, and discussions of the site 

distribution model equations are provided below.

10.6.1 Viosca Knoll Wreck

The Viosca Knoll Wreck Site is an unidentified wooden sailing vessel located 612 m Below Sea 

Level in the Viosca Knoll Area of the GoM. It was likely two-masted vessel, although the exact 

rig type could not be positively discerned from the current data. The Muntz Metal Sheathing, 

abundance of wire rope rigging, and hull construction components indicate a mid- to latenineteenth century construction date. The artifact assemblage, such as the patent stove and the 
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William M. Jowett & Co. water filter indicates the vessel was lost sometime after the mi- 1870’s. 

The Viosca Knoll Wreck Site is eligible for nomination to the National Register of Historic Places

under Criterion D based on archaeology and the site’s potential association with a transitional 

period of maritime commerce in the GoM. Further archaeological investigations of the site are 

likely to yield valuable data on the construction characteristics of merchant sailing vessels and 

shipboard life in the mid- to late- nineteenth century.

10.6.2 7,000 Ft Wreck

The 7,000 Foot Wreck site represents the remains of a small wooden two-masted sailing vessel

and was probably fore-and-aft rigged. Vessels with this style of rig required only small crews and 

were common in the coastal and fishing trades. The steering gear housing on the 7,000 Foot Wreck 

indicates it was probably an American-built vessel and the deck layout is similar to that of New 

England fishing vessels of the same period. The vessel’s wire rope rigging, hull construction, and 

ship components indicate a mid- to late- nineteenth century construction date. The recovered 

compass indicates the vessel was lost sometime post 1874. The Viosca Knoll Wreck Site is eligible 

for nomination to the National Register of Historic Places under Criterion D based on archaeology 

and the site’s potential association with a transitional period of maritime commerce in the GoM. 

Further archaeological investigations of the site are likely to yield valuable data on the construction 

characteristics of merchant sailing vessels and shipboard life in the mid to late nineteenth century.

10.6.3 Ewing Bank Wreck

The Ewing Bank Wreck Site is an unidentified wooden sailing vessel located 621 m BSL in the 

Ewing Bank area of the GoM. The limited artifact assemblage, and lack of ship components and 

rigging make analysis of the Ewing Bank Wreck challenging.The Muntz Metal Sheathing, ceramic 

assemblage, and hardened copper fasteners indicate a mid-nineteenth century construction date. 

The ironstone ceramic designed with the“Pharaoh Cameo” stylehandle suggests a post-1870 

sinking date. The moderately sharp bow, rounded turn-of-the-bilge, and broad beam suggest that 

the Ewing Bank Wreck was a sailing merchant vessel. The Ewing Bank Wreck Site is eligible for 

nomination to the National Register of Historic Places under Criterion D based on archaeology 

and the site’s potential association with a transitional period of maritime commerce in the GoM. 

Further archaeological investigations of the site are likely to yield valuable data on the construction 

characteristics of merchant sailing vessels from the mid nineteenth century.

10.6.4 Green Lantern Wreck

The Green Lantern Wreck Site is an unidentified wooden sailing vessel located 915 m BSL in the 

Green Canyon area of the GoM. The possible Muntz metal sheathing, patent iron windlass, and 

hull construction components indicate a likely late nineteenth century construction date. The 

artifact assemblage, particularly the Simeon L. & George H. Rogers Co. fork and Wood and Sons 

Ltd. ceramic dish conclude the vessel had to have sunk after 1910 and likely within the first quarter 

of the twentieth century. The Green Lantern Wreck Site is eligible for nomination to the National 

Register of Historic Places under Criteria C and D. It is eligible under Criterion C because it 

exhibits unique naval architecture characteristics in its construction, particularly at the stern. It is 

eligible under Criterion D based on archaeology and the sites potential association with a 
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transitional period of maritime commerce in the GoM. Further archaeological investigations of 

the site are likely to yield valuable data on the construction characteristics of merchant sailing 

vessels and shipboard life in the mid to late nineteenth century.

10.6.5 Gulfoil Wreck

Gulfoil was registered as a “407 foot class” tanker built of steel construction. The ship was 

constructed at New York Shipbuilding in Camden, New Jersey in 1912. Gulfoil was the first U.S. 

tanker to incorporate the British tradition of longitudinal frames in its construction. Gulfoil was 

sunk by the German U-boat 506 on 16 May 1942. The ship rests upright, relatively intact in on 

the seafloor, site supports a great deal of marine life, and is an excellent example of pre-WWII

U.S. ship construction. Gulfoil displays 1912 U.S. oil tanker construction with a bridge amidships, 

2 masts/cranes and catwalks connecting the bridge to the engine room located aft. The ship design

is a plain head with a rounded stern typical of oil tankers of the period. It is constructed of steel 

and incorporates longitudinal framing introduced as the Isherwood system of ship construction.

The U.S. tanker SS Gulfoil is eligible for nomination to the National Register of Historic Places 

under Criteria A, C, and D. It is eligible for nomination under Criterion A for its role in U.S. 

commerce during WWII. Additionally, the wreck of Gulfoil denotes a significant period in 

American history as a casualty of WWII in the GoM and demonstrates the effectiveness of German 

submarine operations in U.S. waters. Under Criterion C, it is eligible for nomination as it

demonstrates a period of national significance in transitional naval architecture by being the first 

U.S. tanker to utilize longitudinal framing in its construction. Longitudinal framing continues to 

be a tradition in building modern vessels. Under Criterion D, it is eligible for nomination because 

its continued study will allow researchers the opportunity to further develop formulas to predict 

and describe artifact scatters on deepwater wreck sites. 

10.6.6 Gulfpenn Wreck

Gulfpenn was built in 1920 by Sun Shipbuilding and Dry Dock Company, an affiliate of Sun Oil 

Company, Chester, Pennsylvania. The Atlantic, Gulf, and West Indies Steamship Line owned 

Hull No. 40, originally christened Agvihavre, until being sold to the Gulf Oil Corporation. 

Agvihavre, was one of many steel tankers built by the Sun Oil Company’s yard to compensate for 

WWI shipbuilding shortages. The vessel’s keel was laid on April 2, 1920, and the ship launched 

June 16, 1921 (Kavanagh et al. 2001). The steel hull had a plain head and an elliptical stern. 

Gulfpenn was sunk by the German U-boat 506 on 13 May 1942. The ship rests upright on the 

seafloor but is broken into two sections and has a large associated debris field. The site supports a 

great deal of marine life and is an excellent example of pre-WWII U.S. ship construction.

The Gulfpenn archaeological site is eligible for nomination to the National Register under Criteria

A and D. It is eligible for nomination under Criterion A for its role in U.S. commerce during 

WWII, a time in world history when the industrial power of Germany was in direct opposition to 

the industrial might of the United States. Additionally, the wreck of Gulfpenn denotes a significant 

period in American history as a casualty of WWII in the GoM and demonstrates the effectiveness 

of German submarine operations in U.S. waters. Under Criterion D, it is eligible for nomination 

because its continued study will allow researchers the opportunity to further develop formulas to

predict and describe artifact scatters on deepwater wreck sites.
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10.6.7 Site distribution equations

The Deep-Wreck I (OCS Study MMS 2007-015) Debris Distribution Model was used to help 

understand how the tankers Gulfoil and Gulfpenn sank, based on the distribution of artifacts on the 

seafloor. Combining that information with deceleration formulas to estimate the distances the 

tankers traveled after being torpedoed proved invaluable in understanding the full wrecking event 

and site formation processes at those wreck sites. If the actual location of such an attack or other 

catastrophic event leading to a sinking is not known, but the necessary data are available, 

researchers should also be able to use the same methodology to calculate projected search areas

and work back from the wreck location to determine the location of the initial attack/event. The 

same methodology could then be used to find additional material (scattered artifact fields) related 

to a wreck site that may be a good distance away and possibly even outside the original survey 

area for a site. Locating such material would not only help document the remains on the seafloor, 

but also aid in understanding the events on the surface that led to the sinking. This would not be 

limited to only battle field scenarios, but any event such as an explosion, collision, etc. that led to 

a ship sinking. The authors are now applying these methods to wrecks such as the Robert E. Lee

and U-166 sites, other World War II casualties, andother wrecks sites found in deep water.
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11 EDUCATION AND OUTREACH 

11.1LOPHELIA II CURRICULUM: UNDERSTANDING DEEP-SEA CORAL ECOLOGY 

Recognizing the value of helping students understand the mission, importance and challenges of 

energy management, we developed a curriculum based on the real-life practices of prioritizing 

exploratory energy drilling sites while minimizing ecosystem impact. The curriculum was inspired 

by the mission of the Lophelia II scientific research project, and was developed with significant 

contributions from several members of the project team (see Acknowledgements section in 

Teachers Guide in Appendix F-1. The curriculum targets high school level students in biology 

and environmental science and references cruise logs, seafloor video and relevant multimedia 

modules to provide an authentic context for students. 

Our approach in developing the curriculum follows the principles of Problem Based Learning 

(PBL). According to Barrows and Kelson (1993), PBL is a curriculum and a process. A PBL 

curriculum typically consists of carefully selected problems that demand from the learner 

acquisition of critical knowledge and problem-solving proficiency, and the PBL process typically 

replicates the commonly used approach to resolving problems or meeting challenges encountered 

in life and career. The Lophelia II curriculum is designed around a real-life based Challenge 

Scenario – an activity in which students adopt the role of marine scientist to address the challenge 

of prioritizing potential drilling sites while minimizing ecosystem impacts. To address the 

challenge, students work through six instructional lessons to obtain the necessary background 

knowledge to determine which exploratory sites represent the least impact to deep-sea coral 

communities. 

The curriculum’s six lessons introduce students to: 1) the organisms typically found in deep-sea 

coral communities, 2) the basic biology of corals, 3) the requirement for hard-bottom substrate for 

coral development, 4) the impact of ocean acidification on corals, 5) the importance of currents 

for dispersal and food delivery, and 6) the food web supported in a coral ecosystem. Through these 

lessons, students learn what Lophelia needs to survive and where these conditions may be found 

on the seafloor, so that students can then identify which areas may be considered sensitive habitat. 

Techniques for how scientists approach studying such ecosystems are also embedded in the 

lessons. In the challenge scenario, students learn about trade-offs in resource and ecosystem 

management, and develop an understanding of the processes and information used in making 

decisions around resource management as they prepare their “Environmental Impact Assessment 

and Prioritization” Reports. Each of the lessons incorporate links to specific NOAA 

OceanExplorer content, primarily from the Lophelia II signature cruises as well as other relevant 

GoM cruises and learning modules, providing real-world context and background information to 

students as they work through the unit. 

11.2 OCEAN LITERACY PRINCIPLES AND FUNDAMENTAL CONCEPTS

This curriculum was developed in accordance with National Science Education Standards and 

Ocean Literacy Principles. Ocean literacy is defined by seven essential principles supported by 

detailed fundamental concepts. The fundamental concepts are comparable to those underlying the 
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National Science Education Standards. Each lesson in the curriculum touches on one or more 

ocean literacy essential principles and fundamental concepts. These principles and concepts are 

identified within each lesson. 

11.3TEACHER GUIDE AND SUPPORT MATERIALS

A 90-page Teachers Guide was prepared to help teachers implement the curriculum and is included 

in Appendix F-1. For each lesson in the Teachers Guide, teacher notes contain focus questions, 

learning objectives, ocean literacy principles addressed, appropriate background information, and 

links to appropriate reference material available on the NOAA OceanExplorer website. Lessons 

also come with support materials necessary for the particular lesson. The Challenge Scenario 

includes 5 seafloor maps, map notes and a student handout in the form of a Memo describing the 

challenge. Lesson 1 includes three photomosaics, each with six high-resolution images, a 

dichotomous key of seafloor organisms, and a teacher’s key to the organisms in each photomosaic. 

Lessons 3, 4 and 6 include PowerPoint presentations along with slide notes to help teachers present 

new material to students. All lessons include reproducible student handouts. All support materials 

are found either within the Teachers’ Guide or on the accompanying files on the DVD. 

11.4 CURRICULUM TESTING

The curriculum was tested with four high school teachers and their students in the Seattle Public 

School district in the Spring of 2011. Teachers were provided notebooks with all materials in 

printed form and online training before using the curriculum. They were asked to keep records of 

how long each lesson took, what worked well and what did not, and suggestions for modification. 

Feedback was obtained both in written form and through interviews, and suggestions were 

incorporated into the final version. Teachers received a small honorarium for their efforts. 

11.5 DISSEMINATION

The final curriculum was released at the National Science Teachers Associationconference in 

Phoenix, Arizona in December 2012. Twenty-five teachers attended a short workshop on the 

project and received a DVD with all support materials included. Feedback from conference 

workshop attendees was highly positive, including one teacher’s comment expressing appreciation 

that the DVD included all the materials (e.g., maps, student handouts, videos, PowerPoint 

presentations, website links) necessary to instruct students. 

The curriculum was designed to be disseminated online. The Teachers Guide and support materials 

including maps are formatted to be easily downloaded and printed on standard size paper, for ease 

of use in classroom settings. Videos and PowerPoints may also be downloaded for classroom use. 
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11.6 VIDEO PRODUCTION

11.6.1 Video Production Summary

A massive amount of video was collected aboard the Lophelia II Expeditions. In total, about 50 

hours of video were collected and archived in 2008, with 1200 hours of video in 2009, and 885 

hours in 2010. The ROV Jason II is equipped with four video cameras, and each recorded 

compressed video (.mpeg format) on DVD media. A total of 24 hours of broadcast quality “Best 

of” video was collected on DVCam tape media from the three-chip camera on Jason II in 2009. 

Additional broadcast quality footage of ship operations (three hours) was recorded to Mini-DV 

tape format using a Sony three-chip camera shooting standard definition. Video recording in 2009 

was standard definition, but recording in 2010 was upgraded to high-definition format.

The “Best of” video from 2009 was edited (or reduced) into two different output products: 1) 

moderate resolution (360 x 240) videos in .mov format (240 minutes) showing highlights from all 

sites, suitable for public lectures and presentations and 2) broadcast resolution (720 x 480) 

highlight videos (16 minutes) from 10 select sites, suitable for broadcast media. The 10 selected 

sites were: West Florida Shelf, DeSoto Canyon, Viosca Knoll 826, Viosca Knoll 906, Mississippi

Canyon 751, Green Canyon 852, and Garden Banks 535, the Gulfpenn wreck, a 7,000-ft wreck, 

and the Green Lantern wreck. Durations range from 1–3 minutes, depending on the site. Videos 

include title cards, rights-free music, and logos from NOAA and BOEM.

The broadcast quality highlights from 2009 were ultimately intended for the 20-minute

documentary about the Lophelia II project, but the short format also helped to accomplish interim 

tasks, such as public outreach and education. Currently, 12 videos are uploaded to YouTube with 

text and metadata approved by project Principal Investigators. The clips may be searched using 

the term ‘Lophelia II’. The videos have proven popular online. The median Lophelia II video was 

viewed 7,500 times. Videos from West Florida, Garden Banks, VK826, and VK906 were each

viewed more than 7,500 times since March 2010. Two clips hosted by NOAA Office of Ocean 

Exploration ranked very highly. “Extraordinary Redeye Gaper” had 88,313 views and “Seafloor 

Walking: Graneledone Octopus” had 16,837 views. 

The YouTube format has also proven useful in other ways. For example, clips were previewed 

online by Dan Rather's news team for a June 22, 2010, broadcast on HDNet featuring Dr. Erik 

Cordes. The production quality and popularity of the highlight videos also gained an invitation for 

the collection to appear in Google Earth's new Ocean layer. A Google Earth tour has been rendered 

from the highlights with text, metadata, and web links relevant to our research (Figure 11-1). (The 

tour can be downloaded from: http://db.tt/IwvW2d). The Lophelia II tour in Google Earth is a 

narrative progression (with a beginning, middle, and end) that tells the story of Lophelia II using 

approved text with the best available footage from 2008 and 2009 (see Table 11-1 for text and 

links). Essentially, the Google Earth tour functioned as a storyboard for the final intended 20-

minute documentary of the three-year expedition. 

The final 20-minute documentary was designed to incorporate new elements, such as personal 

interviews with project scientists, more music, more institutional logos, new graphic illustrations, 

title cards, and multi-lingual closed-captioning for foreign language speakers and the hearing 

impaired. Interviews with scientists captured overarching themes of geology, biology, archeology, 
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management, and technology. Researchers were able to explain their science in their own words, 

relaying a palpable sense of passion and excitement for ocean exploration. A full transcript of the 

documentary is available in Appendix F-2. The total running time for the documentary was 23

minutes, including logos and credits.

Currently, the documentary can be streamed online, viewed on smartphones, and/or downloaded 

at full resolution from NOAA’s Ocean Explorer website and Bureau of Ocean Energy and 

Management on YouTube. NOAA’s website offers a variety of file formats and file sizes for 

download, while the BOEM YouTube site offers state-of-the-art spatial and temporal tracking and 

unprecedented access for interested viewers from all over the world.

NOAA’s Ocean Explorer website:

http://oceanexplorer.noaa.gov/explorations/12Lophelia/media/movies_2/Lophelia_video.html

BOEM YouTube website:

http://www.youtube.com/watch?v=MZG_qPKEvAk

Figure 11-1. Video tour on Google Earth.

Additional venues may become available for the Lophelia II videos in the near future. There is 

potential for the 23-minute documentary or the short highlights to appear in the Sant Hall of the 

Oceans at Smithsonian Institution’s National Museum of Natural History in Washington, DC.

Other venues include the Blue Ocean Film Festival in San Francisco, CA or the Beneath the Waves 

Film Festival, which tours around the world. These venues would make the Lophelia II video 

widely available for perpetuity, for public viewing and download to computers and smartphones 

around the world.
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Table 11-1.

Lophelia II Tour in Google Earth

Location Lat Lon Depth RunT Description

West Florida 

Slope

26.20467 -84.7225 459 1:47 Submerged ridges near 500 m depth on the West Florida slope 

were the first targets for the Lophelia II: Reefs, Rigs, and Wrecks 

2009 Expedition. Many animals were seen, including the deepsea coral Lophelia pertusa, our flagship species (white with zigzag branches). Fish included a shark, silver dollar, sea robin, and 

an Atlantic roughy. Small Lophelia colonies grew on the twiglike skeletal axis of a black coral. Jason II collected Lophelia, 

and a yellow sea fan with a brittle star attached.

http://www.youtube.com/watch?v=aa9yoUZYQp8

DeSoto Canyon 

583

28.38602 -87.3873 2455 1:49 Scientists peer through the lens of Jason II at 2,500 m (8,200 ft) 

depth near DeSoto Canyon. Submarine canyons are steep-sided 

features that cut through the continental slope. At this site, an 

exposed rock bed juts from the abyssal plain, providing substrate 

for bamboo and black corals, a chemosynthetic mussel

community, and a deep-sea octopus. This was the deepest dive 

of Lophelia II 2009 expedition.

http://www.youtube.com/watch?v=r2Q-a-nNoTI

Viosca Knoll

(VK) 826

29.15636 -88.01608 496 1:24 A school of alfonsino fish swims over Viosca Knoll 826 

(VK826), a natural deep reef, and an example of the kind of 

habitat scientists will study aboard the Lophelia II expeditions. 

VK826 refers to a BOEMRE leasing system for oil and gas. 

BOEMRE sponsored researchers aboard Lophelia II will 

compare the biota of natural reefs to biota on artificial reefs, like 

oil rigs and shipwrecks. Ocean chemistry is measured using a 

rosette of Niskin bottles and a Conductivity-Temperature-Depth 

(CTD) deployed over the side of the boat.

 http://www.youtube.com/watch?v=J6dAS1ScmbA

Gulfpenn Wreck 28.44 -89.32 561 1:05 The USS Gulfpenn was transporting 90,000 barrels of gasoline 

when it was torpedoed by German submarine U-506 on May 13, 

1942. Twenty-five crewmembers survived the attack, but 

thirteen died. The ship now lies at 550 m in the GoM, encrusted 

by an amazing community of Lophelia pertusa coral, fish, and 

invertebrates.

http://www.youtube.com/watch?v=8Ir6uJfvYwQ

Mississippi 

Canyon (MC) 751

28.19072 -89.79861 455 2:52 The Mississippi River continues below the sea surface in the 

GoM to 4000 m depth as a submarine canyon called the 

Mississippi Canyon. Nutrients from the river support abundant 

deep-sea coral communities. Callogorgia and Lophelia corals 

settle and grow on carbonate outcrops, feeding on suspended 

matter. Brittlestars, squat lobsters, and urchins occur on most 

colonies. Active methane seeps are in the immediate vicinity. 

The “infaunal” community is observed using sediment pushcores.

http://www.youtube.com/watch?v=CyMSvhx_r0A

7,000-ft Wreck 28.33 -87.93 2256 1:14 A 7,000-ft wreck is the deepest known shipwreck in the GoM. 

The original name is unknown, but archaeologists suspect the 

wooden-hulled vessel was a two-masted schooner. The bow and 

ships wheel are encrusted with rusticles and other signs of life. A 

date inscribed on the compass recovered from the wreck 

indicates the ship sank after June 1, 1875. The ship's wheel is 

prominent on the wreck.
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Table 11-1. Lophelia II tour in Google Earth (continued)

Location Lat Lon Depth RunT Description

http://www.youtube.com/watch?v=5kYOIBCbeVk

Viosca Knoll 906 29.09839 -88.40345 300 1:15 Viosca Knoll 906 is home to a Leiopathes black 

coral community. The number “906” identifies the 

oil and gas lease block that encompasses area. Black 

corals can be incredibly long lived. Living colonies 

are white, salmon, or orange. Only the skeleton is 

black. The branches are habitat for fishes and 

crustaceans. Barrelfish were one type of commercial 

fish that was present in the area. Geneticists aboard 

Lophelia II will decode the black coral DNA to 

determine whether we see one species or many.

http://www.youtube.com/watch?v=U6IqiLHT7nU

Garden Banks 

(GB) 535

27.42292 -93.59727 600 1:30 The westernmost aggregation of Lophelia pertusa

coral in the North Atlantic was discovered in an oil 

and gas lease block called Garden Banks 535 during 

Lophelia II 2009 Expedition. Lophelia colonies 

occurred on large carbonate outcrops near 500 m 

depth. Many squat lobsters and fishes were seen in 

and around the coral colonies, including slimeheads, 

tinselfish, and a chain catshark.

http://www.youtube.com/watch?v=85YtHgRAV3I

Green Lantern

Wreck

27.71667 -90.71667 915 1:13 C&C Technologies, Inc. found the Green Lantern

wreck during a deep-tow survey in 1996, and their 

archeologists investigated in 2004. The wreck is an 

unidentified copper-clad sailing vessel that measures 

approximately 20 m in length. The wreck is named 

for one of the ships lanterns found lying just outside 

the stern. The lantern caught the attention of the 

archeologists. It was embossed with the word 

Estribor, Spanish for “starboard.” Just like modern 

ships, historic vessels ran a green light on the 

starboard side and a red lantern on the port side.

http://www.youtube.com/watch?v=6BermqpuVis

Green Canyon 

(GC) 852

3:08 Green Canyon is a submerged ridge at 1410 m (4625 

ft) depth in the GoM with high diversity of deep-sea 

corals. The ridge was explored by the science party 

of the Lophelia II 2009 Expedition in August, 2009 

using the Jason II ROV. The research was part of an 

ongoing initiative by Bureau of Ocean Energy 

Management, Regulation and Enforcement (now 

BOEM) and National Oceanic Atmospheric 

Administration to understand deep-sea habitat in the 

Gulf. The project now provides important baseline 

information to the Natural Resource Damage 

Assessment resulting from the Deepwater Horizon

oil spill.

http://www.youtube.com/watch?v=1Lii6f5cd2M

Attribution: Videos by Aquanautix. Music is by Kevin MacLeod, 

www.incompetech.com. Lophelia II 2009: Reefs, 

Rigs, and Wrecks Expedition was sponsored by the 

Minerals Management Service (later BOEMRE, 

now BOEM) and National Oceanic and Atmospheric 

Administration (NOAA). 

Total 15:57
523

12 IMPROVED PREDICTION OF COLD-WATER CORALS

OCCURRENCE IN THE GULF OF MEXICO

12.1 BACKGROUND

Understanding the environmental and geographic distribution of species is an ongoing challenge 

in deep-sea ecology. Distribution patterns in the deep-sea are generally poorly resolved, in part 

due to the difficulty and expense of surveying deep water regions, and the vast area of unexplored 

seafloor (e.g., Gage 2004). It has been estimated that only 0.0001% of the deep-sea has been 

surveyed (Gjerde 2006) and much of this past work has focused on a few relatively well studied 

areas (e.g., North Atlantic seamounts). A better understanding of species’ biogeographical 

distributions is fundamental for designing and implementing management plans, shaping future 

research efforts, and assessing anthropogenic impacts. Given the recent increase in the rate and 

scale of anthropogenic disturbance to the deep-sea, it is imperative to more fully characterize the 

distribution and niche of deep-sea species before these ecosystems are irrevocably altered or lost.

Cold-water corals comprise the majority of the world’s known coral species and support 

biodiversity hotspots in the deep-sea by providing structurally complex habitats. They fill vital 

ecological roles in the deep-sea through nutrient cycling, habitat creation, and carbon 

sequestration. Due in part to their importance in structuring deep-sea communities, it is 

increasingly important to understand how ecological factors interplay with species’ traits to 

influence observed distributions. Currently, the factors that are primarily responsible for 

controlling cold-water coral distributions are only partially understood. Previous work has shown 

that corals cluster on elevated seafloor features where the current regime and topography combine 

to generate locally accelerated flows, which increases food availability, larval dispersal, and 

sediment and waste removal (Frederiksen et al. 1992; Mortenson et al. 2001; Masson et al. 2003; 

White et al. 2005; Guinotte et al. 2006). The availability of hard substrata is generally thought to 

be necessary for larval recruitment (e.g., Freiwald et al. 1999), however, settlement may also occur 

on mixed bottoms, small substrata including shells, cobbles, or boulders, and man-made objects 

(Wilson 1979; Gass and Roberts 2006). The success of cold-water corals also appears to be 

influenced by the aragonite or calcite saturation state, with numerous field reports that most coldwater coral aggregations occur at higher saturation states (Guinotte et al. 2006; Lunden et al. 2013), 

as well as experimental results that suggest an energetic cost associated with calcification at low 

saturation states (e.g., Turley et al. 2007; Maier et al. 2009, but see Thresher et al. 2011). Finally, 

cold-water corals are heterotrophic filter feeders that are reliant on the transfer of energy from 

surface primary production of which only 1-3% reaches the deep-sea (Deuser 1986). Therefore, 

high surface productivity and nutrient availability are expected to be positively linked with coldwater occurrence (e.g., Tittensor et al. 2009).

Ecological niche models are being increasingly used to characterize the distribution of both 

terrestrial and marine organisms by statistically coupling occurrence records with environmental 

parameters. This approach has recently gained traction in the deep-sea, where extensive direct 

observations are logistically difficult, and occurrence data are often sparse. A number of deep-sea 

species distributions have been recently characterized using a variety of modeling techniques, 

including squat lobsters (Wilson et al.2007), echinoids (Pierrat et al. 2012), and several species of 
524

cold-water gorgonians (Leverette and Metaxas 2005; Bryan and Metaxas 2006, 2007; Tong et al. 

2012; Yesson et al. 2012; Quattrini et al. in press). In addition, North Atlantic and global 

populations of L. pertusa have been modeled using a variety of techniques (Dolan et al. 2008; 

Guinan et al. 2009; Tittensor et al. 2009; Howell et al. 2011; Davies et al. 2008; Davies and 

Guinotte 2011). However, these studies generally used low-resolution environmental data (30 m2

- 1°; but see Dolan et al. 2008) and did not include the GoM. Populations in the GoM are

genetically isolated (Morrison et al. 2011) and L. pertusa may occupy a different niche space in 

other biogeographical areas than in the GoM. 

There is an immediate need to better establish the baseline niche of cold-water corals in the GoM

and to develop quantitative methodology for locating novel coral sites. We built ecological niche 

models for five species of cold-water corals in the GoM: Lophelia pertusa, Leiopathes glaberrima, 

Callogorgia gracilis, and C. americana delta and C. a. americana. Our specific goals were to: 1) 

develop high-resolution, local-scale models at commonly studied sites in the GoM to quantify 

niche and predict novel occurrences at each site, 2) generate a lower-resolution, large-scale model 

for each species to allow for the inclusion of additional environmental data and to facilitate 

discovery of novel cold-water coral sites in unexplored regions of the GoM, and 3) evaluate and 

compare the niche space occupied by each species in the GoM.

12.2 METHODS

12.2.1 Occurrence Data

Video data collected during ROV and human-operated vehicle (HOV) dives spanning from 2005 

– 2011 were reviewed to extract cold-water coral occurrences, which were linked to USBL 

navigational data (slant error of 1%) to yield a set of georeferenced occurrence points for each site. 

Occurrences observed on video were supplemented with observation and collection logs; however, 

we found that observations recorded during dives generally underreported occurrences. Additional 

occurrences were obtained from Schroeder et al. (2005) and the Smithsonian National Museum of 

Natural History database. Only occurrence records obtained from submersible or ROV dives were 

included from the Smithsonian National Museum of Natural History database to avoid potential 

inaccuracies in the recorded location of samples collected by trawling or unknown sources. To 

ensure that only spatially explicit presence points were included in analyses, we removed duplicate 

points that occurred within the same multibeam grid cell. L. pertusa and L. glaberrima were 

generally highly visible and easily distinguishable from other species, making the probability of 

detection extremely high in surveyed areas, eliminating a common source of modeling error.

Callogorgia spp. were not visually distinguishable but were identified to species level both 

genetically and morphologically (Quattrini et al. in press; see Section 4.3.1).

12.2.2 Environmental Data 

Loca- scale models: Bathymetric data were acquired in 2008 using a Kongsberg-Simrad EM1002 

multibeam echosounder (95 kHz, 111 beams, 150° coverage) mounted on the R/V Nancy Foster. 

This yielded high quality bathymetric data, which were gridded at either 5 or 8 m and used to 

derive subsequent environmental layers using ArcGIS 10.1 (ESRI). Aspect, curvature, rugosity, 

and slope, believed a priori to structure coral distribution, were calculated using the Digital 

Elevation Map Surface Tool (v. 2.1.292, Jennes 2011). Aspect, which measures the directionality 
525

of the steepest slope, has an inherent circularity when measured in radians so a cosign 

transformation was applied to create an index of northness on a continuous scale from -1 (facing 

south) to +1 (facing north), and a sine transformation to create an index of eastness, on a scale 

from -1 (facing west) to +1 (facing east). Curvature assigns more positive values to more convex 

seafloor surfaces, and more negative values to more concave surfaces. Slope was measured in 

degrees using the 4-cell method (Fleming and Hoffer 1979) which has been shown to marginally 

outperform Horn’s method (Horn 1981), the default in ArcGIS (see Jones 1998). Rugosity is a 

measure of seafloor complexity, calculated as the ratio of surface area to planar area (Jenness 

2004). We calculated bathymetric position index (BPI) using the Land Facet Corridor Designer 

(v.1.2.848, Jenness et al. 2013). BPI quantifies the relative position of points to their surrounding 

features. Depressions are assigned a negative value and positive features are assigned positive 

values. Values of zero indicate either a flat surface or a continuous slope. Importantly, this measure 

is inherently scale dependent (see Lunblad et al. 2006), so we calculated BPI at a number of scales: 

5, 25, 100, and 500 m. Seismic data were obtained at a relatively high resolution (generally <10 

m2) for most sites (excluding GC140 and GC246) from BOEM 3D seismic surface reflectivity 

images. Each image was georeferenced and then reclassified using a histogram equalized scheme 

to classify areas of each site by dividing the initial image values into four categories according to 

their intensity values: very high, high, low, and very low. 

Callogorgia mosaic models – To ecologically distinguish closely related sister taxa in the 

Callogorgia genus, additional environmental variables believed a priori to structure gorgonian 

populations were included in a separate set of Callogorgia spp. models: seep activity, temperature, 

salinity, dissolved oxygen, and calcite saturation state (Ωcalcite). This necessitated a modified data 

processing method, in which variables were restricted to a 50 m buffer around dive tracks to allow 

for the inclusion of data that lacked site-wide coverage. Temperature, salinity, Ωcalcite, and 

dissolved oxygen data were interpolated to the same resolution as the available bathymetry data 

using the inverse distance weighted technique in ArcGIS. Points identified from video as seep 

habitat were buffered to a 25 m radius, and regions within buffers were considered to be seep 

environments and regions outside of buffers were considered to lack seep activity. Other 

topographical variables were derived from bathymetry as described above. In order to standardize 

models to the same study area, all sites containing any of the Callogorgia species were mosaicked 

together to form a single raster layer for model generation and subsequent niche evaluation 

(GC140, GC234, GC246, MC751, MC885, VK826, and VK862/906). 

Large-scale models: Bathymetry data were obtained at a 25 m2resolution from the Texas Sea 

Grant College Program for an area in the northern GoM covering over 67,000 km2. Aspect, BPI, 

curvature, rugosity, and slope were derived as described above, except that BPI was calculated at 

scales of 25, 100, and 1000 m. Hard bottom locations were available as a polygon layer from 

BOEM and were converted to a 50 m2resolution binomial raster (1=hard bottom, 0=soft bottom). 

Student’s t-tests were used to determine if model predictions varied significantly with substrate 

type. Phosphorus and nitrate surface data were obtained from the National Oceanographic Data 

Center. Chlorophyll a surface data (a proxy for primary productivity) were obtained from

Moderate Resolution Imaging Spectroradiometer data via the Giovanni online data system 

maintained by the NASA GES DISC. Aragonite saturation states (Ωarag) were obtained at depth 

from a 2010 cruise on the R/V Ronald Brown (Lunden et al. 2013; see Section 3.2) and the 2007 

Gulf of Mexico and East Coast Carbon cruise (Wang et al. 2013). Although L. glaberrima and 
526

Callogorgia spp. utilize the calcite form of calcium carbonate instead of the aragonite form, we 

included only aragonite because the two datasets were calculated from the same carbonate data. 

Surface nutrient and aragonite saturation state data were interpolated to a 25 m2resolution using 

the inverse distance weighted technique in ArcGIS. A consensus model was created by training a 

model using the occurrence points for all species. 

12.2.3 Model Generation and Evaluation

Numerous niche modeling approaches exist, ranging from relatively simple regression, linear, or 

additive models (see Pearce and Ferrier 2000), more complex genetic algorithms and neural 

networks (Stockwell and Noble 1991; Recknagel 2001), and sophisticated machine-learning 

algorithms (Hirzel et al. 2002, 2006; Phillips et al. 2006). Most traditional methods for modeling 

species’ distributions require both presence and absence data. However, obtaining accurate 

absence data in the deep-sea is usually impossible due to the prohibitive amount of time and 

expense required. Therefore, datasets on the absence of deep-sea species are typically sparse and 

biased due to the limited field of view of the ROV and lack of systematic observations across all 

of the potentially occupied substrata. Regardless of the environment, habitat suitability predictions 

from absence data may be inaccurate or misleading due to dispersal limitation, biotic interactions, 

detection error, or historical reasons (see Hirzel et al. 2002). Therefore, we used the machinelearning MAXENT algorithm (v3.3.3k, Phillips et al. 2006) because it utilizes pseudoabsence 

(background) data rather than true absence data, and has consistently outperformed other presenceonly techniques (Elith et al. 2006; Tittensor et al. 2009). Models were created using default 

MAXENT parameters (convergent threshold = 10-5, regularization=1, number of background 

points = 10,000, default prevalence = 0.5; see Phillips and Dudik 2008), however, we increased 

the number of maximum iterations to 5,000 to ensure model convergence. During model training, 

10% of occurrences were withheld and used to test each model, a process known as k-fold cross 

validation (k=10) that outperforms other commonly used validation techniques (Kohavi 1995). A 

jackknifing procedure, in which models are constructed using different combinations of variables, 

was used to determine the percent contribution of each variable to final models. To further assess 

variable contributions, we generated response curves that show how model predictions change as 

a function of the range of values for the variables that contributed the most information to models. 

To assess whether predictions were significantly different among seismic classes (very high, high, 

low, very low), we employed a one-way ANOVA followed by pair-wise Holm-Sidak post-hoc 

tests, or a Kruskal-Wallis ANOVA with a Tukey post-hoc test if the data violated either the 

normalcy or equal variance test (SigmaPlot 12.3). Since correlations between variables confound 

interpretation of variable importance, we assessed the Pearson-product movement correlation 

between each variable in JMP (v.9.0.0, SAS Institute). However, even highly correlated variables 

were not removed from models (with the exception of calcite, see above) because MAXENT has 

been shown to be robust with regards to correlated inputs (Phillips et al. 2006). Each model 

produced two continuous outputs, a raw output for subsequent statistical analysis (see below), and 

a more intuitive logistic output ranging from 0-1. Commonly referred to as the habitat suitability 

index, the logistic output indicates the probability of occurrence at each locality, visualized as a 

habitat suitability map. 

The predictive ability of models was assessed by comparison to a random model using a thresholddependent exact binomial test, with the null hypothesis stating that the model predicts test points 

no more accurately than a random model. The ability of models to accurately predict test data was 
527

also assessed using a threshold-independent receiver operating characteristic curve, which tests 

the ability of the model to correctly rank both presences and absences. The true positive rate 

(sensitivity) of the model is plotted against the false positive rate (1 – specificity). Receiver 

operating characteristic curves are evaluated by the area under the curve (AUC) metric that 

indicates the probability that the model will rank true occurrences over negative occurrences. The 

maximum theoretical AUC is 1.0 and a random model has a theoretical AUC of 0.5. Values greater 

than 0.7 are indicative of ‘good’ model performance, while values above 0.9 are considered 

‘excellent’ (Swets 1988; Fielding and Bell 1997).

As a final test of model accuracy, a model was generated from an independently collected dataset 

of L. pertusa occurrences from photographic transects conducted at VK826 by the autonomous 

vehicle Sentry (WHOI) in 2009 (see Section 4.1). Seven transects averaging 885±123 m in length 

were conducted in the area covering the large knoll at the center of the site in an ordered, 

predetermined fashion and were therefore subject to less bias than occurrences observed from 

ROV and HOV dives. Georeferenced photographs were taken at regular, overlapping intervals and 

analyzed for living or dead L. pertusa cover. A single MAXENT model was trained using only 

these occurrences with identical environmental layers and parameters as the original VK826 

model. The resulting model was compared to the originally calculated model.

12.2.4 Niche Evaluation

To determine the niche breath of each species, we used the statistical package ENM Tools (v1.3, 

Warren et al. 2008, 2010). ENM Tools measures niche breath in accordance to the inverse 

concentration (B1) metric developed by Levins (1968) and reintroduced by Nakazato et al. (2010). 

A larger index value indicates that the species occupies a wider niche space, and a smaller value 

indicates that the species occupies a more specialized niche; given by the following equation where 

p equals the proportion of occurrences found in the environment i: 

12.2.5 Niche Breadth: 1/B = Σpi2

To determine the extent to which each species’ niche overlaps, we calculated the I metric for each 

pair of niche models (Warren et al. 2008). The I metric is a modified Hellinger distance (van der 

Vaart 1998) ranging from 0-1, where x and y are the two species being compared and p is the 

probability of each species occurring in the geographic space i:

Niche overlap (I): I (pX, pY) = 1 -

1

2

√∑i(√pX,i − √pY,i

)

2

A value of 0 indicates that niches are completely discordant and a value of 1 indicates that niches 

are identical. We followed the guidelines established by Rödder and Engler (2011) for interpreting 

the I metric: values below 0.2 indicate no or limited niche overlap, values between 0.2 – 0.4 

indicate low overlap, values 0.4 – 0.6 indicate moderate overlap, and values greater than 0.6 

indicate high overlap. To determine if each species’ niche was more or less similar than expected 

by chance, we employed the identity test in ENM Tools. The identity test measures niche overlap 

(I) between a null distribution of random models. If the actual value of I between two species’ 

niches is significantly lower than the null distribution, the niches are considered to be divergent. 

If the environmental conditions available to each species are considerably different (e. g., species 
528

occupy separate depth zones), it is possible to observe significant divergence under the identity 

test, even if the species occupy similar niches in reality. Therefore, we also employed the 

background test in ENM Tools for the Callogorgia spp. mosaic models, because the species do 

not coexist at any site and it is therefore likely that that they occupy different conditions. The 

background test compares the actual niche overlap (I) between species to two null distributions of 

models generated in the environment available to each species. If the observed overlap between 

species’ niches is significantly lower than both of these null distributions, than the niches are 

considered to be significantly divergent. 

We generated a rough estimate of the geographic range of each species by buffering occurrences 

by 20 km and dissolving overlapping areas in ArcGIS (sensu Nakazato et al. 2010). While this 

method is unlikely to be representative of the true range of the species in the GoM, it provides a 

uniform method to compare the relative range of each species within the study area. We then 

estimated niche filling, the proportion of suitable area that was actually occupied, by comparing 

the geographic range to a binary prediction of suitability where ‘suitable’ habitat was defined by 

the sensitivity-specificity sum maximization approach (Liu et al. 2005).

12.2.6 Predictive Modeling Program

To allow researchers who are unfamiliar with modeling techniques to apply our model to their own 

data to predict cold-water coral locations, we incorporated models for each species into the 

downloadable program ‘Cold-water Coral Modeler’, freely available along with a user’s manual 

on the Cordes website. The program was constructed in C# using Microsoft Visual Studio 2012. 

It utilizes the lambda file created by MAXENT during model generation to project a predictive 

model onto bathymetric data input by the user, generating a habitat suitability map in a novel 

geographic region. Input data can be gridded at any resolution using any spatial reference but must 

match the input layers used in our original models. 

12.3RESULTS AND DISCUSSION

12.3.1 Local Scale Models

MAXENT models were constructed for L. pertusa at seven sites in the GoM: VK826, VK862/906, 

MC751, MC885, GB535, GC234, and GC354 (Table 12-1), visualized as habitat suitability maps 

(Figure 12-1). Evaluation of models with test data showed that all models were robust. The average 

test AUC for all sites was 0.967±0.02, with a lowest AUC value of 0.934 at VK826. All models 

significantly outperformed a random model (exact binomial test, |p|<0.01; Table 12-1). Niche 

breadth (inverse concentration) averaged 77.9±67.8x10-3across all sites and ranged from 13.47 at 

GB535 to 153.17 at GC234. VK862/906, MC751, and GC354 all had intermediate niche breadths 

of 31.70, 30.94, and 30.98 respectively. AUC was significantly correlated with niche breadth 

(Pearson’s correlation, r = -0.86, p<0.05), indicating that models performed better when L. pertusa

occupied a narrower niche space. The number of occurrences used to train models was not 

correlated with either AUC (Pearson’s correlation, r = -0.11, p=0.82) or with niche breadth 

(Pearson’s correlation, r = -0.32, p=0.48). 
529

Table 12-1.

Input data and model evaluation for L. pertusa local scale models. The number of spatially 

explicit occurrences and the average AUC±s.d. are shown with significance marked (exact 

binomial test, *=p<0.01, ** p<0.001). The two primary explanatory variables for each model are 

listed along with the percentage of information contributed by each variable, as determined by 

jackknifing 

In all models, suitability indices for L. pertusa were higher at positive BPI values, indicating that 

elevated seafloor features provided better habitat than depressions or flat areas (Figure 12-2). BPI 

calculated at a large scale (500 m) was the primary or secondary explanatory variable in five out 

of seven models, contributing an average of 56.5% of information in those models (Table 12-1).

While rugosity was among the top two explanatory variables only at GB535 (percent contribution 

of 19.6%), suitability indices increased with greater rugosity at all sites, plateauing at a rugosity 

value of approximately 1.2. The higher suitability indices observed at positive BPI and rugosity 

values demonstrated that L. pertusa has a clear preference for more complex, elevated topography, 

and indicated that depressions and flat areas were generally sub-standard habitat. Elevated regions 

have been shown to increase local current speeds, boosting the transport of food and nutrients 

(Thiem et al. 2006), increasing larval supply (Piepenburg and Müller 2004) and reducing sediment 

deposition (Rogers 1994). These results were not surprising, because previous work has often 

associated the presence of L. pertusa and other cold-water corals with steep, elevated, and complex 

topography even at large scales (e.g., Bryan and Metaxes 2006; Davies et al. 2008, but see 

Tittensor et al. 2009), an association known as the ‘enhanced current hypothesis’ (see Masson et 

al. 2003). The high-resolution bathymetry used here would only further reveal the ability of 

relatively small features to affect local current regimes. In addition, since established colonies 

increase sedimentation rates by acting as a barrier to current flow, the presence of large L. pertusa 

structures may have facilitated historical mound growth, creating a feedback loop that further 

elevated successful colonies (Paull et al. 2000). 

Site No. of

occurrences

Average AUC

± s.d.

Niche breadth

(x 10-3)

Variable 1 Variable 2

VK826 1242 0.934±0.004** 104.47 BPI-500 m (57.6%) Depth (40.2%)

VK826 

(Sentry)

454 0.956±0.012** 86.02 BPI-500 m (65.9%) Depth (30.0%)

VK862/906 425 0.975±0.006** 31.70 BPI-500 m (96.4%) BPI-100 m (1.1%)

MC751 166 0.986±0.007** 30.94 Depth (51.9%) BPI-500 m (29.4%)

MC885 11 0.952±0.045* 180.61 BPI-500 m (38.9%) Hard bottom (23.8%)

GB535 26 0.996±0.002** 13.47 BPI-500 m (60.1%) Rugosity (19.6%)

GC354 29 0.979±0.037** 30.98 Depth (42.5%) Hard bottom (27.5%)

GC234 15 0.947±0.073* 153.17 Depth (42.7%) Hard bottom (41.3%)
530

Figure 12-1. Local-scale habitat suitability models for L. pertusa. Warmer colors indicate 

locations that are predicted to be more suitable. Black points indicate occurrences used 

to train and test the models. Note differences in scale.
531

Figure 12-2. Response of the predicted habitat suitability for L. pertusa to changes in 

bathymetric position index (BPI) calculated at the 500 m scale for local scale 

models. Error bars indicate standard deviation. In general, locations with higher 

BPI values were predicted to be more suitable for L. pertusa.
532

However, at VK826, MC751, MC885, GC354, and GC234, suitability indices peaked before the 

maximum BPI values at each site, indicating that there may be an obstacle to colonization or 

survival at the shallowest features of a site. This finding is consistent with recent studies that 

recorded reduced diversity on the summits of seamounts relative to the surrounding slopes, thought 

be influenced in part by extreme hydrological forces, exposure to oxygen-minimum zones, or finescale topography of the summit (see review by Clark et al. 2010). At sites with large mound 

structures (e.g., VK826), the summits may experience dramatically accelerated currents that have 

been shown to prevent the recruitment of other invertebrate larva (e.g., Mullineaux and Garland 

1993) and negatively affect L. pertusa feeding rates (Purser et al. 2010). Alternatively, it is 

plausible that since locations with extremely high BPI values were not as common at most sites, 

they were less likely to be inhabited simply by chance. 

Depth was the primary or secondary explanatory variable in four out of seven L. pertusa models, 

contributing an average of 35.5% of information in those models (Table 12-1). Suitability indices 

tended to be higher in the shallower regions of each site, with highest index values between depths 

of approximately 300-600 m (Figure 12-3), within the known depth range for L. pertusa in the 

GoM. The presence of hard bottom (measured as relative surface seismic reflectivity) was the 

secondary explanatory variable in three models (MC885, GC354, and GC234), contributing an 

average of 30.9% of information. At all sites, the suitability index was significantly higher when 

seismic reflectivity was very high or high (Kruskal- Wallis, p<0.01, post-hoc Tukey p<0.05; 

Figure 12-4). This finding confirms previous work suggesting that L. pertusa and other coral 

species require hard substrate for the initial attachment and recruitment of larva (Wilson 1979), 

and may largely explain the absence of corals at locations that are otherwise suitable.
533

Figure 12-3. Response of the predicted habitat suitability for L. pertusa to changes 

in depth (m) in local scale models. Error bars indicate standard deviation. 

In general, L. pertusa had the highest suitability indices between depths 

of approximately 300-500 m. 
534

Figure 12-4. Response of the predicted habitat suitability for L. 

pertusa to changes in seismic reflectivity data, averaged 

across all sites. Higher reflectivity values indicate the 

presence of hard substrata. Locations with very high 

reflectivity values had significantly higher suitability 

indices than sites with low or very low reflectivity values 

(Kruskal- Wallis p<0.01, post-hoc Tukey p<0.05). Error 

bars indicate standard deviation. 

An additional L. pertusa model was constructed at VK826 using only the occurrences obtained 

from Sentry transects as a general test of model accuracy. This test model had an AUC of 0.956 ±

0.012 and significantly outperformed a random model (exact binomial test, p<0.01; Table 12-1). 

The test model was significantly correlated with the original VK826 model (Pearson’s correlation, 

r=0.91, p<0.01), and the models were not significantly different from each other under the identity 

test (I=0.95, p>0.05). The high degree of similarity between the original model and a test model 

built with more structured transect data verifies the accuracy of the original model and strongly 

suggests that the potentially deleterious effects of bias caused by user-directed ROV and HOV 

sampling were minimal or non-existent. When compared to the original VK826 habitat suitability

map (Figure 12-5), the test model and original model appeared to predict similar locations to be 

the most suitable, but the test model tended to over-predict large areas as being highly suitable. In 

part, this may have resulted from the lower sample size (test n=454, original n=1242) and reduced 

spatial coverage of the transect sampling, or because dead colonies were included as occurrences 

in the analysis of transect photographs. Including dead colonies as occurrences may have caused 

unsuitable or barely suitable areas to be predicted as highly suitable. The presence of dead skeletal 

structures may indicate that the location was previously suitable due to unknown historical or 

stochastic factors, but recently became unsuitable. Alternatively, they may represent areas with 

relatively poor environmental conditions but high propagule pressure, a combination that might 

allow recruitment but inhibit the growth and long-term success of adults. Therefore, the re-analysis 
535

of this dataset to remove dead colonies as occurrences may even further increase the similarity 

between the original model and the test model. 

Figure 12-5. Enlarged view of habitat suitability maps for local scale L. pertusa models at 

VK826. A) Original VK826 model. B) Test model trained using only the 

transect occurrence data from Sentry. The two models were highly correlated 

(Pearson’s correlation, r=0.91, p<0.01) and were not significantly different from 

each other under the identity test (I=0.95, p>0.05). Warmer colors indicate 

locations that are predicted to be more suitable. Black points indicate 

occurrences used to train the models. 

Models were constructed for Leiopathes glaberrima at two sites: VK826 and VK906 (Figure 12-

6). Both models performed well, with an average AUC of 0.958±0.011 at VK826 and 0.983±0.003 

at VK862/906 (Table 12-2). At both sites, BPI calculated at a large scale (500 m) was the primary 

explanatory variable, contributing 50.4% of information at VK826 and 49.7% at VK862/906. 
536

Response curves revealed that suitability indices were generally higher at BPI values greater than 

20 (Figure 12-7). Interestingly, at VK826 suitability decreased when BPI was greater than 20, 

while at VK862/906, suitability did not peak until 60, the maximum BPI value found at the site. 

Depth was the secondary explanatory variable for both models, contributing 43.8% of information

at VK826 and 43.9% at VK862/906. Suitability at VK826 was highest at depths between 450-475 

m (Figure 12-8). At VK862/906, there was a peak in suitability at a depth of approximately 300 m 

corresponding with the top of the mound in VK862, and a second peak between 400-450 m 

corresponding with the Roberts’ Reef cold-water coral mound in VK906 (Figure 12-8). Averaged 

across both sites, suitability was significantly higher when seismic reflectivity was very high 

(ANOVA, p<0.01, post-hoc Holm-Sidak p<0.01; Figure 12-9). The L. glaberrima model at each 

site was highly similar to its corresponding L. pertusa model, suggesting that the species occupy 

a similar niche at these sites; consistent with frequent observations of L. glaberrima growing on 

or immediately adjacent to L. pertusa structures, particularly around the periphery of Roberts’ 

Reef. Niche breadth varied widely between the two sites, ranging from 39.12x10-3at VK862/906 

to 112.52x10-3at VK826; mirroring the pattern observed for L. pertusa at these sites.

Figure 12-6. Local scale habitat suitability models for L. 

glaberrima. Warmer colors indicate locations that are 

predicted to be more suitable. Black points indicate 

occurrences used to train and test the models. Note 

difference in scale.
537

Table 12-2. 

Input data and model evaluation for L. glaberrima local scale models. The number of spatially 

explicit occurrences and the average AUC±s.d. are shown with significance marked (exact 

binomial test, ** p<0.001). The two primary explanatory variables for each model are listed 

along with the percentage of information contributed by each variable, as determined by 

jackknifing 

Figure 12-7. Response of the predicted habitat suitability for L. glaberrima to changes in 

bathymetric position index (BPI) calculated at the 500 m scale for local scale 

models. Error bars indicate standard deviation.

Site No. of

occurrences

Average AUC

± s.d.

Niche breadth

(x 10-3)

Variable 1 Variable 2

VK826 386 0.958±0.011** 112.52 BPI-500 m (50.4%) Depth (43.8%)

VK862/906 253 0.983±0.003** 39.12 BPI-500 m (49.7%) Depth (43.9%)
538

Figure 12-8. Response of the predicted habitat suitability for L. glaberrima to changes 

in depth (m) for local scale models. Error bars indicate standard deviation.

Figure 12-9. Response of the predicted habitat suitability for L. glaberrima to 

changes in seismic reflectivity data, averaged across VK862/906 and 

VK826. Error bars indicate standard deviation.
539

We constructed a single model for C. gracilis at GC140 (Figure 12-10), the only site in the GoM

where it has been confirmed to be present. The model outperformed a random model (exact 

binomial test, 1-tailed p<0.01) and had an average test AUC of 0.931±0.018 (Table 12-3). Depth 

contributed the most information to the model (44.4%), followed by BPI-500 m (34.7%). Response 

curves revealed that the highest suitability indices were between depths of 250-300 m (Figure 

12-11) and BPI-500 m values greater than 20 (Figure 12-12). C. gracilis had the largest niche 

breadth of any species with an inverse concentration of 207.55 (Table 12-3). Accordingly, a large 

portion of the shallow, southern portion of the site was predicted to be suitable, with peaks in 

suitability generally tracking with shallow ridges. Areas within the modeled optimum depth range 

(250-300 m) of C. gracilis were generally predicted to contain suitable habitat, reflecting its wide 

niche breadth and suggesting that depth is the primary factor structuring its distribution at this site. 

While it is possible that factors not included in model creation (eg. Ωcalcite, water chemistry, 

currents, food supply) restrict its dispersal to, or recruitment and growth at other sites in the GoM, 

C. gracilis’ wide niche breadth indicates that this species should occur more frequently at sites 

within its depth range. Therefore, while C. gracilis is currently only known to exist in the GoM at 

GC140, it seems likely that other shallow (<300 m) sites may contain undiscovered C. gracilis

populations).

Table 12-3. 

Callogorgia spp. Local-scale niche modeling results. The average test AUC of each model is 

listed along with model significance (exact binomial test, * p<0.05, ** p<0.01). The two primary 

explanatory variables for each model are listed along with the percentage of information 

contributed by each variable, as determined by jackknifing

Species Site Bathymetry

Resolution

No. of

Occurrences

Mean AUC

± S.D.

Niche 

breadth

(x 10-3)

Variable 1 Variable 2

C. a. americana VK862/906 5 5 0.811 ± 0.246 NA NA NA

C. a. americana GB299 25 86 0.986 ± 0.006** 45.64 Depth (81.6%) Rugosity (13.3%)

C. gracilis GC140 5 152 0.931 ± 0.018** 207.55 Depth (44.4%) BPI-500 m (34.7%)

C. a. delta VK826 5 26 0.913 ± 0.148** 145.85 Depth (68.8%) BPI-500 m (17.6%)

C. a. delta GC234 8 15 0.966 ± 0.028* 153.17 Depth (42.6%) Hard bottom (22.1%)

C. a. delta GC246 8 8 0.949 ± 0.056 NA NA NA

C. a. delta MC751 5 83 0.985 ± 0.018** 34.40 Depth (41.4%) Hard bottom (30.4%)

C. a. delta MC885 8 40 0.979 ± 0.008** 59.55 Depth (44.9%) BPI-500 m (33.5%)
540

Figure 12-10. Local scale habitat suitability models for Callogorgia spp. Warmer colors 

indicate locations that are predicted to be more suitable. Black points indicate 

occurrences used to train and test the models. Note differences in scale. GC140 = 

C. gracilis, VK862/906, GB299 = C. a. americana, VK826, GC234, MC751, 

MC885, GC246 = C. a. delta.
541

Figure 12-11. Response of the predicted habitat suitability for Callogorgia spp. to 

changes in depth (m) for local scale models. Error bars indicate standard 

deviation. GC140 = C. gracilis, VK862/906, GB299 = C. a. americana, 

VK826, GC234, MC751, MC885, GC246 = C. a. delta.
542

Figure 12-12. Response of the predicted habitat suitability for Callogorgia spp. to 

changes in BPI calculated at the 500 m scale for local scale models. 

Error bars indicate standard deviation. GC140 = C. gracilis, 

VK862/906, GB299 = C. a. americana, VK826, GC234, MC751, 

MC885, GC246 = C. a. delta.
543

Models were constructed for C. a. americana at VK862/906 and GB299 (Figure 12-10). Only five 

spatially explicit colonies were observed at VK862/906, resulting in poor model performance 

(AUC of 0.811±0.246) that was not significantly better than a random model (exact binomial test, 

1-tailed p>0.10; Table 12-3). Since the model was statistically no better than random, no additional 

statistical tests were conducted. The GB299 model was constructed using bathymetry from the 

National Oceanographic Data Center gridded at 25 m2 because higher resolution bathymetry data 

were not available for this site. The model outperformed a random model (exact binomial test, 1-

tailed p<0.01) and had a high AUC of 0.986±0.006. Depth contributed 81.6% of information to 

the model, with the highest suitability indices occurring below depths of 350 m (Figure 12-11). 

Rugosity contributed 13.3% of information to the model, with the suitability indices peaking at

approximately 1.2. C. a. americana had an intermediate niche breadth of 45.64x10-3at GB299, 

likely reflecting its apparent restriction to sites deeper than 350 m. A comparison of model 

predictions to the bathymetry of GB299 suggests that C. a. americana is restricted to the slopes 

and summits of two large knolls in the center of the site, either reflecting a preference for largescale elevated features, or simply a restriction to shallower depths. Within its suitable depth range, 

C. americana appeared to prefer more complex topographical features as evidenced by higher 

suitability indices at larger rugosity values. Therefore, other sites in the GoM within this depth 

range and containing complex topographical features may contain additional C. a. americana 

colonies.

Local-scale models were constructed for C. a. delta at VK826, GC234, GC246, MC751, and 

MC885. With the exception of GC246, all models outperformed a random model (exact binomial 

test, |p|<0.05) and exhibited high performance with AUC values ranging from 0.966±0.028 at 

GC234 to 0.985±0.018 at MC751 (Table 12-3). The GC246 model had a paucity of spatially 

unique occurrences (n=8) and performed relatively poorly with an AUC of 0.949±0.056. It was 

not significantly better than a random model (exact binomial test, p>0.05), therefore no additional 

statistics were calculated. Niche breadth varied greatly among sites, ranging from 34.40x10-3at 

MC751 to 153.17x10-3at GC234. Depth was the primary variable in all four significant models, 

contributing between 41.4% and 68.8% of information (Table 12-3). Response curves for all sites 

revealed that C. a. delta had the highest predicted suitability in a relatively broad depth range 

between approximately 440-625 m (Figure 12-11). At VK826 and MC885, BPI-500 m was the 

secondary variable, with contributions of 17.6% and 33.5% respectively. At all sites, suitability 

indices peaked between BPI-500 m values of 5-15, with decreasing suitability at maximal BPI 

values (Figure 12-12). At GC234 and MC751, hard bottom was the secondary explanatory 

variable, contributing 22.1% and 30.4% of information respectively. Across all sites, suitability 

indices were significantly higher at locations with very high seismic reflectivity values (ANOVA, 

p<0.01, post-hoc Holm-Sidak p<0.05: Figure 12-13) These results suggest that the presence of 

local topographic highs alone is not a good predictor of C. a. delta presence and abundance at all 

sites, and that depth and the availability of hard substrate are likely the determining factors that 

structure this species’ distribution in the GoM. 
544

Figure 12-13. Response of the predicted habitat suitability for C. a. delta to changes in 

seismic reflectivity data, averaged across VK826, MC751, MC885, and GC234. 

Locations with very high reflectivity values had significantly higher suitability 

indices (ANOVA, p<0.01, post-hoc Holm-Sidak p<0.05) than sites with low and 

very low reflectivity values. Error bars indicate standard deviation.

12.3.2 Callogorgia spp. Mosaic Models

MAXENT models were also constructed for C. a. americana, C. gracilis, and C. a. delta from a 

mosaic of all sites where any Callogorgia species was found (GC140, GC234, GC246, MC751, 

MC885, VK826, VK862/906). GB299 was not included in mosaics because the available 

bathymetry was considerably courser than the additional variables included in the mosaic models 

(salinity, temperature, dissolved oxygen, and Ωcalcite). The C. a. americana model had an average 

AUC of 0.781±0.266 s.d. and did not significantly outperform a random model (exact binomial 

test, 1-tailed, p=0.25; Table 12-4). The low performance of this model was likely because only 

five spatially explicit presence points were available for sites with high resolution bathymetry. No 

additional statistics were calculated for this model.
545

Table 12-4.

Model input and evaluation for Callogorgia spp. mosaic models. The average test AUC of each 

model is listed along with model significance (exact binomial test, * p<0.05, ** p<0.01). The 

two primary explanatory variables for each model are listed along with the percentage of 

information contributed by each variable, as determined by jackknifing

The C. gracilis model significantly outperformed a random model (exact binomial test, 1-tailed, 

p<0.001) with an average AUC of 0.977±0.004 s.d. (Table 12-4). The variable that contributed the 

most information to the model was depth (percent contribution of 70.6%) followed by salinity 

(10.7%), and dissolved oxygen (9.3%). Salinity was highly correlated with depth (Pearson 

correlation r = -0.83, p<0.001) within the sampled area and provided minimal additional predictive 

power not already provided by depth as determined by a lack of reduction in AUC. Dissolved 

oxygen had a weaker correlation with depth (Pearson correlation, r = -0.30, p<0.001); however an 

additional model run without dissolved oxygen did not reduce the AUC, indicating that dissolved 

oxygen also provided minimal predictive power. Suitability indices were highest between depths 

of 220 and 300 m, with a maximum index value of 0.96 at a depth of 253 m (Figure 12-14). This 

species is known to have a shallower distribution, with an individual in the Smithsonian collection 

documented from 87 m depth in the GoM, and is found throughout the Caribbean (Cairns and

Bayer 2002). Therefore, the records used for the modeling only cover a small portion of its realized 

niche, and the large niche breadth is an indication that it is likely to be relatively common in the 

shallower (80-200 m) waters of the GoM. 

Species Sites No. of

Occurrences

Mean AUC

± s.d. Variable 1 Variable 2

C. gracilis GC140 152 0.977 ± 0.004** Depth (70.6%) Salinity (10.7%)

C. a. americana VK864/906 5 0.781 ± 0.266 NA NA

C. a. delta

GC234,GC246, 

MC751, MC885

VK826

178 0.995 ± 0.002** Seep (58.3%) Ωcalcite
546

Figure 12-14. Suitability indices of Callogorgia spp. relative to various 

environmental parameters for mosaic models. Open circles = C. 

gracilis, closed circles = C. a. delta. 

The C. a. delta model was similarly robust, significantly outperforming a random model (exact 

binomial test, 1-tailed, p<0.001) with an average AUC of 0.989±0.01 SD (Table 12-4). Jackknifing 

revealed that seep activity (58.3%) contributed the most information to the model, followed by 

calcite (19.8%), and salinity (9.4%). C. a. delta occurrences had significantly higher suitability 

indices at localities with seep activity (average suitability index = 0.61) than at non-seep localities 

(average suitability index = 0.37) (t-test, t=14.1, p<0.001). The highest suitability index (0.99) 

corresponded with an Ωcalcite value of 2.2; however, high suitability indices (>0.9) occurred at all 

Ωcalcite values encountered in the C. a. delta range (Figure 12-14). 
547

Together, identity and background tests suggested that niche use differed significantly between C. 

a. delta and C. gracilis and was primarily driven by depth for C. gracilis and the presence of seeps 

for C. a. delta. The niche models of C. gracilis and C. a. delta had a very low degree of overlap (I 

metric = 0.014), and the identity test revealed that this overlap was significantly lower than the 

null distribution (p<0.01). Under the background test, the observed overlap between niche models 

(I metric) was significantly lower than the null distributions (p<0.01), rejecting the possibility that 

these species artificially show divergence due to differences in their access to environmental 

conditions. Therefore, these species appear to exhibit a high degree of niche divergence driven 

primarily by adaptation to a specific depth range, with C. a. delta occurring over a wider, deeper 

range than C. gracilis. While MAXENT has been shown to be robust with regard to correlated 

inputs (Phillips et al. 2006), correlated variables should be treated with caution when interpreting 

the percent contribution of variables to models. It is likely that one or more factors that covary 

with depth, including pressure, temperature, salinity, dissolved oxygen, pH, Ωcalcite, resource 

availability, and distance from shore, are the causal factor of the observed divergence rather than

depth itself. 

Interestingly, the presence of seep activity significantly increased the suitability of C. a. delta

habitat. There is also some indication that C. a. delta may gain nutritional input from seep activity 

(see Section 4.2.2 but also Becker et al. 2009). While the correlation with the areas of seep activity 

may primarily be due to the increased availability of substrate in the form of authigenic 

carboncarbonate, this species also appears to be more tolerant to seep conditions than its 

competitors, thereby giving it access to increased levels of local, deep-sea productivity.

Topography was surprisingly unimportant in the mosaic Callogorgia spp. models given that it is 

frequently stated that octocorals prefer local topographic highs (Bryan and Metaxas 2006; Tong et 

al. 2012). Colonies of Callogorgia were repeatedly observed in dense patches on fairly flat 

substrates, particularly at MC885 and GB299, indicating that relatively flat surfaces are also 

suitable habitat for some octocoral species. Our tactic of using a mosaic of sites across a large 

depth gradient may have dampened the role topography may play at smaller scales, but even in the 

local scale Callogorgia spp. models (Table 12-3), depth was the primary contributing variable at 

every site. BPI calculated at the 500 m scale did contribute between 17 and 34% of information at 

GC140, VK826, and MC885, however when these models were generated excluding BPI, there 

was no reduction in AUC. Therefore, while topographic variables were generally informative, they 

did not contain considerable predictive information not already provided by other variables, and 

likely did not strongly influence niche divergence among these species. 

12.3.3 Large-Scale Models

A single model was constructed for each species at a coarser resolution (25 m2) for an area of the 

northern GoM covering approximately 67,000 km2(Figure 12-15). Model performance was 

excellent, with AUC values ranging from 0.976 to 0.997 (Table 12-5). All models significantly 

outperformed a random model (exact binomial test, |p|<0.05; Table 12-5). C. a. americana was the 

most specialized species with a niche breadth of 5.74 x 10-3, and L. pertusa occupied the broadest 

niche with a breadth of 43.58 x 10-3. L. glaberrima, C. a. delta, and C. gracilis all had similar, 

intermediate niche breadths of 21.41 x 10-3, 26.98 x 10-3, and 21.41 x 103respectively. In 

agreement with its wide niche breadth, L. pertusa was predicted to be the most prevalent species 

in the GoM, filling 76.3% of the largest range size (10,067 km2). C. gracilis had the smallest 
548

predicted range size (1,358 km2) but filled 91.7% of its suitable habitat. For all species, there were 

relatively large regions that were predicted to be suitable but not known to be inhabited. It is 

possible that models simply overestimated the suitable habitat for each species. Niche models rely 

on the theory that a species’ distribution is largely driven by the portions of its ecological niche 

that can be readily quantified. While there is ample evidence for this theory (see James et al. 1984; 

Schoener 1989), it is also clear that other factors, such as seawater chemistry, temperature, biotic 

interactions, disease, seasonal variability, or resource availability, may partially structure 

distributions but are intractable in modeling efforts (e.g., MacArthur 1972; Case and Taper 2000).

It is plausible that unoccupied regions that were predicted to be suitable may in reality be 

unsuitable due to any number of ecological factors that could not be included during model 

creation. However many unfilled locations occurred in regions that have not been well surveyed, 

and it seems likely that extensive cold-water coral populations remain to be discovered in the GoM. 

Modeling efforts, while useful, should not replace extensive field explorations. Instead, models 

should support field operations by quantitatively assessing collected data and informing research 

efforts in unexplored regions; in turn, field studies should be used to ground truth, verify, and 

refine model predictions. 

Figure 12-15. Large scale habitat suitability model for cold-water corals in the northern 

GoM. Warmer colors indicate locations predicted to be more suitable. Black 

triangles indicate the most intensively surveyed sites (west to east: GB299, 

GC354, GC140, GC246, GC249, MC751, MC885, VK862, VK906, VK826).
549

When all large-scale models were considered in conjunction, AUC had a significant negative 

correlation with range size (Pearson correlation, r = -0.90, p=0.037), and a non-significant but 

negative correlation with niche breadth (Pearson correlation, r = -0.67, p=0.22). L. pertusa had the 

lowest AUC (0.976±0.004) despite having the greatest number of occurrence points, likely because 

it occupies the largest range (10,067 km2) and has the widest niche breadth (43.58 x 10-3). This 

was not surprising, since AUC is expected to be artificially inflated when species have small ranges 

and are more specialized (Guisan and Hofer 2003; Elith et al. 2006). Niche breadth was not well 

correlated with niche filling (Pearson’s correlation, r = 0.10, p=0.87), but had a marginally 

significant positive correlation with range size (Pearson’s correlation, r = 0.82, p=0.09). This 

relationship was expected as larger ranges generally encompass a wider range of environmental 

conditions (Nakazato et al. 2010). The small sample size (n=5) likely inhibited achieving 

significance for some niche metrics comparisons; the addition of more taxa may resolve these 

relationships. 

Table 12-5. 

Large scale modeling results and niche characteristics for each species. The average test AUC of 

each model is listed along with model significance (exact binomial test, ** p<0.01). The two 

primary explanatory variables for each model are listed along with the percentage of information 

contributed by each variable, as determined by jackknifing.

Species No. of

Occurrences

Average 

AUC

± s.d.

Niche 

breadth

(x 10-3)

Niche filling

(%)

Range size

(km2)

Variable 1 Variable 2

L. pertusa 450 0.976±0.004** 43.58 76.3% 10,067 Hard bottom 

(40%)

Depth 

(24%)

L. glaberrima 242 0.985±0.009** 21.41 72.3% 6,644 Hard bottom 

(65%)

Depth 

(21%)

C. a. delta 111 0.993±0.004** 26.98 35.3% 7,054 Depth (82%) BPI-1000 

m (8%)

C. a. americana 88 0.996±0.001** 5.74 44.4% 2,683 Hard bottom 

(71%)

Depth 

(21%)

C. gracilis 76 0.997±0.001** 21.41 91.7% 1,358 Depth (88%) Ωarag (8%)

Depth was the primary or secondary variable in every large scale model, explaining between 21% 

and 88% of the distribution of each species (Table 12-5). The highest suitability indices for L. 

pertusa and L. glaberrima occurred between depths of 300-600 m, between 450-850 m for C. a. 

delta, between 350-400 m for C. a. americana, and between 200-400 m for C. gracilis (Figure 

12-16). BPI calculated at the 1000 m scale contributed 8% of information to the C. a. delta model, 

but BPI calculated at any scale was generally uninformative in large scale models. Given its 

importance in L. pertusa and L. glaberrima local scale models, this may indicate that the effects 

of topography are predominantly localized and influence distributions on small spatial scales, as 

evidenced by the lack of importance of current flow and related variables in low resolution global 

modeling efforts (e.g., Tittensor et al. 2009). Depth was significantly but weakly correlated with 

BPI calculated at the 1000 m scale (Pearson’s correlation, r = 0.05, p<0.05: Figure 12-16 Table 

12-6), the 100 m scale (Pearson’s correlation, r = 0.077, p<0.05), and the 25 m scale (Pearson’s 
550

correlation, r = -0.003, p<0.05), indicating that the importance of depth in models was likely 

attributable to other depth-related variables such as pressure, salinity, temperature, or Ωarag rather 

than a factor related to the topography of the seafloor. The presence of hard substrata explained 

40% of the distribution of L. pertusa, 65% of the distribution of L. glaberrima, and 71% of the 

distribution of C. a. americana. At all sites, the presence of hard substrata resulted in significantly 

higher suitability indices than locations with unknown or soft substrata (t-test, two-tailed |p|<0.05;

Figure 12-17), again confirming that hard substrate is a necessary prerequisite for cold-water coral 

recruitment. 

Figure 12-16. Response of the predicted habitat suitability for cold-water coral species to 

changes in depth (m) for large scale models. Error bars indicate standard 

deviation. Only depths shallower than 1000 m are shown.
551

Table 12-6.

Pearson’s correlation values (r) among environmental variables used to train large 

scale models. Significant correlations (two-way p<0.05) are indicated with an asterisk. 

Significant correlations with an r>0.10 are highlighted in grey- N=673,646

B

PI

-

10

00 

Ωarag Chl a Plan Profil

e

Curvatur

e

Depth Eastnes

s

NO3

- Northne

ss

PO4

3- Rugosit

y

Seismi

c

Slope BPI25

BPI100

BPI-1000 1

-

0.003*

-

0.009*

0

.204*

-

0.207*

0

.249*

0

.052*

0

.000

-

0.004*

0

.015*

-

0.006*

0

.188*

-

0.052*

-

0.011* 0.215* 0.374*

Ωarag 0 1

0

.426*

-

0.002

-

0.001

0

.000

-

0.132*

0

.000

0

.645*

0

.050*

0

.399*

-

0.010*

-

0.028*

-

0.077* 0.000 -0.000

Chl A 0 0 1

-

0.000

-

0.001

0

.000

-

0.445*

0

.000

0

.543*

0

.076*

0

.488*

0

.001

-

0.015*

-

0.097*

-0.000 -0.001

Plan 0 0 0 1

-

0.359*

0

.769*

0

.004*

-

0.000

-

0.002

-

0.006*

-

0.001

0

.101*

-

0.004* 0.020* 0.687* 0.701*

Profile 0 0 0 0 1

-

0.871*

-

0.004*

0

.000

-

0.001

0

.000

-

0.001

0

.078* 0.000* 0.004*

-

0.744*

-

0.739*

Curvature 0 0 0 0 0 1

0

.004*

-

0.000

-

0.000

-

0.003*

0

.000

-

0.001

-

0.002* 0.007* 0.869* 0.874*

Depth 0 0 0 0 0 0 1

0

.000

-

0.421*

-

0.054*

-

0.547*

0

.001

-

0.088* 0.067* 0.004* 0.008*

Eastness 0 0 0 0 0 0 0 1

0

.000*

-

0.001

0

.001

0

.000 -0.000 -0.001 -0.000 -0.000

NO3

- 0 0 0 0 0 0 0 0 1

0

.068*

0

.681*

-

0.011*

-

0.018*

-

0.099*

-0.000 -0.000

Northness 0 0 0 0 0 0 0 0 0 1

0

.105*

-

0.079*

-

0.031*

-

0.531*

-0.002 -

0.008*

PO4

3- 0 0 0 0 0 0 0 0 0 0 1

-

0.012*

-

0.000*

-

0.152* 0.000 -0.000

Rugosity 0 0 0 0 0 0 0 0 0 0 0 1 0.006* 0.305* 0.026* 0.078*

Seismic 0 0 0 0 0 0 0 0 0 0 0 0 1 0.048*-0.002 -

0.005*

Slope 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0.005* 0.020*

BPI-25 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0.794*

BPI-100 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1
552

Figure 12-17. Response of the predicted habitat suitability for cold-water coral species to the 

presence or absence of hard bottom for large scale models. Error bars indicate 

standard deviation. Suitability was significantly higher at locations with hard bottoms 

at all sites (t-test, two-tailed |p|<0.05).

All species pairs were significantly more ecologically divergent than expected by chance (identity 

test, |p|<0.05; Table 12-7), however the degree of niche overlap (I metric) varied considerably 

among species. L. pertusa and L. glaberrima occupied the most similar niches, with an I metric 

value of 0.724, which suggests a high degree of niche overlap. The large degree of overlap supports 

the similarity of L. glaberrima and L. pertusa local scale models at VK862/906 and VK826, as 
553

well as numerous field observations of L. glaberrima colonies growing on or near L. pertusa 

aggregations. In general, Callogorgia spp. had low overlaps with each other despite their greater 

relatedness. C. a. delta and C. gracilis were the most divergent species, with an overlap value of 

0.162, supporting the high degree of divergence observed between their respective mosaic models. 

C. gracilis and C. a. americana had an overlap value of 0.291, and C. a. delta and C. a. americana

had a slightly higher overlap value of 0.429. In conjunction with variable contributions and 

associated response curves, it appeared that this divergence was primarily driven by changes in 

depth, with C. gracilis occurring at the shallowest depths, C. a. americana at intermediate depths, 

and C. a. delta across the broadest depth range including deeper sites.

Table 12-7. 

Niche overlap (I metric) between the large scale niche models of each species pair. Values closer 

to one indicate greater niche overlap and values closer to zero indicate greater divergence. 

Asterisk indicates that species were more divergent than expected by chance under the identity test 

(α = 0.05).

L. 

pertusa

L. 

glaberrima

C. a. 

delta

C. a. 

americana

C. 

gracilis

L. pertusa 1

L. glaberrima 0.724* 1

C. a. delta 0.678* 0.484* 1

C. a. americana 0.471* 0.658* 0.429* 1

C. gracilis 0.366* 0.643* 0.162* 0.291* 1

554

13 UNDERSTANDING DEEP CORAL DISTRIBUTION PATTERNS

The results of this study have significantly improved our understanding of deepwater coral 

ecosystems in the GoM and beyond. The first cold-water coral mound in the GoM was discovered, 

but in an area of low seismic reflectivity. The geology of this mound revealed that it has been 

developing intermittently for over 300,000 years (Section 9). The shallowest and deepest records 

for Lophelia pertusa in the GoM were located, but on artificial substrata (Section 8). The 

physiological limits of L. pertusa growth and survival with respect to oxygen, temperature and pH 

were determined in the laboratory (Section 7). Significant new archaeological sites were 

discovered, documented, and some were identified, including the Gulfoil wreck that supports one 

of the largest L. pertusa reefs in the Gulf (Section 10). The genetic patterns of deepwater coral 

relationships were revealed in the GoM for the first time (Sections 5.2 and 5.3). Several new 

species of corals and associates were identified and phylogenetic studies have increased our 

understanding of the taxonomy of all corals (Sections 5.1 and 5.2). The communities of animals 

living with the corals were described, and now include over 90 species living with L. pertusa alone 

(Section 4.1 – 4.4). The biogeographic and depth-driven patterns of occurrence of different corals 

and communities in the GoM are described (Section 4.2 to 4.4). The food webs of these 

communities were examined. We confirmed that most corals and associates are not obtaining any 

significant nutrition from seep-derived sources and therefore are not likely to be exposed to seep 

effluent (Section 6). In parallel but separate analyses we also found the first example of a coral 

species that appears to utilize seep production and found its distribution to be tied to seepage 

(Sections 5.1 and 6; Quattrini et al., 2013). 

This study also contributed significantly to our understanding human impacts in the deep GoM. 

In addition to the laboratory studies constraining the sensitivity of L. pertusa to the effects of ocean 

acidification (Section 7) we provide the first data on the progress of ocean acidification in the deep 

GoM (Section 3.1). Although designed for long-term monitoring of natural change in deep water 

coral communities (Section 4.1 and 4.2) our monitoring stations proved quite valuable for analysis 

of the impact from the Deepwater Horizon oil spill to deep water coral communities (Section 4.5). 

Additionally, in response to the spill we explored for and discovered a coral community 7 miles 

from the Macondo well and documented serious impact from the blowout to the corals and 

ophiuroids at this site (White et al., 2012). Continued study of this site has provided the first data 

on the response of corals to impact from the spill and is providing data that allows us to constrain 

the ultimate outcome on the communities (Appendix C-4) 

Building on these accomplishments, perhaps the greatest contribution of this study comes from the 

synthesis of these data. The primary objective of this project was to obtain a robust predictive 

capability for the occurrence of rich cnidarian (primarily scleractinian coral) hard-ground 

communities in the deep GoM. It is only through an examination of everything that we have 

learned that we can achieve this goal: from the site selection process, to the field observations, the 

gathering of oceanographic data, the genetic patterns in coral populations and the lab experiments, 

to the modeling of coral distribution patterns. 

It is commonly held that deep-sea corals colonize hard substrata in areas of high local relief and 

high food availability. While these general statements have held true, they can be greatly refined 

by the knowledge gained in this study. The most important factor in determining the suitability of 

habitat for development of particular coral community types was depth, especially for L. pertusa. 
555

In the modeling, depth is essentially a proxy for a variety of other factors that could be affecting 

the corals, including temperature, dissolved oxygen, pressure, and aragonite saturation state. In the 

laboratory experiments with L. pertusa, the corals ceased growth at an aragonite saturation state 

of 1.06, suffered complete mortality after being exposed to a temperature of 14°C, and complete 

mortality after prolonged exposure to dissolved oxygen concentrations of approximately 1.5 mL·L1

. From our field measurements, L. pertusa often occupies habitats that are very near these critical 

thresholds (particularly at the western Green Canyon and Garden Banks sites for aragonite 

saturation state, VK862 for temperature, and the 500-600 m GC and GB sites for DO). These 

findings indicate that the available coral habitat may be severely reduced as anthropogenic impacts 

to these oceanographic variables intrude on the deeper waters of the Gulf. 

The next factor was typically the presence of hard-grounds, as determined from the relative seismic 

reflectivity of the seafloor. This was a primary tool used in the site selection process, and was 

highly successful. Reflectivity was particularly significant for Callogorgia americana americana, 

likely due to its preference for authigenic carbonate substrate near seeps. However, there were a 

few notable exceptions to the link between seismic reflectivity and coral presence. The first is the 

Roberts’ Reef cold-water coral mound in VK906. This mound and the other less well-developed 

mounds in the immediate vicinity were characterized by anomalously low seismic reflectivity. 

While the sub-bottom seismic profile revealed hard substrate at the base of the mounds, the thick 

accumulation of coral fragments that form the mounds acted to scatter the acoustic signal resulting 

in the low return. The other exception was exemplified at the GB201 site surveyed during the first 

cruise in 2008. This site looked promising from the seismic data, but the hard-grounds apparent in 

the seismic data were covered in a fairly thin layer of sediment. The multibeam bathymetry 

revealed numerous pockmarks around the site, suggesting recent and ongoing sediment expulsion. 

When interpreting the seismic data for indications of habitat suitable for corals, both of these 

features – pockmarks and low-reflectivity mounds – should be taken into consideration. 

The next factor revealed by the modeling effort was local topography, represented by the 

bathymetric position index. This supports the notion that corals prefer locations that are elevated 

above their immediate surroundings. This factor was particularly significant for the black coral, 

Leiopathes glaberrima. Locally elevated patches of hard substrate will provide enhanced current 

flow, which will allow for sediment removal from the corals and resuspension of particulate matter 

that may contribute to the corals’ diet. However, this factor was not significant at the larger scale 

considered in the models. This indicates that it operates at very localized spatial scales, and even 

a small elevation above the surrounding area may be sufficient to render a habitat patch suitable 

for coral growth. 

The consistent finding that depth, seismic reflectivity, and local elevation were the most significant 

factors controlling coral distribution is quite useful to managers and deep-sea explorers alike. 

Potential coral sites may be predicted from the archive of 3D seismic data housed at BOEM along 

with high-resolution, multibeam bathymetry. At the largest scale, models suggest that areas of the 

northern Gulf in the western portion of the Green Canyon area appear to be the most suitable for 

coral growth (Fig. 12-15). Although many of the sites in this study were in that region, more 

emphasis has been placed on the seep communities there, and it remains ripe for exploration for 

additional coral habitats. Once certain areas are identified for exploration or management (i.e. lease 

blocks), smaller, well-defined targets where corals are likely to be present can be generated from 

the models and higher resolution AUV surveys for eventually ground-truthing by AUV or ROV 

visual surveys. 
556

14 COMMERCIAL FISHERIES IN THE GULF OF MEXICO AND 

POTENTIAL IMPACTS TO DEEPWATER CORALS

Commercial Fisheries in the Gulf of Mexico 

and Potential Impacts to Deepwater Corals

Report

January 2010
557

Commercial Fisheries in the Gulf of Mexico 

and Potential Impacts to Deepwater Corals

BY

TDI-BROOKS INTERNATIONAL, INC.

PREPARED UNDER BOEM CONTRACT

M08PC20028

JANUARY 2010

TDI-Brooks International Inc.

14391 South Dowling

College Station, TX 77845, USA. 
558

Acknowledgements

This report was prepared by Mr. Douglas Weaver, Dr. Thomas Shirley, and Dr. Ian MacDonald. 

Mr. Weaver wa a doctoral student and research biologist at the Harte Research Institute for Gulf 

of Mexico Studies, Texas A&M University, Corpus Christi (HRI-TAMUCC). Dr. Shirley is the 

Chair of Biodiversity and Conservation Science at (HRI-TAMUCC). Dr. MacDonald is a 

professor in the Department of Oceanography at Florida State University. Fisheries statistics from 

the reef fish log books were provided by Mr. Josh Bennett and Mr. Brion Cook of the NOAA 

Fisheries Service, Southeast Fisheries Science Center, Miami, FL. Fisheries statistics from the 

shrimp data log books were provided by Dr. Jim Nance, NOAA Fisheries Service, Galveston 

Laboratory. Dr. Steve Branstetter of the NOAA Fisheries Service, Southeastern Fisheries Science 

Center, St. Petersburg, FL, provided information on the current status of various deepwater 

fisheries in the Gulf of Mexico. Additional information on the royal red shrimp fishery and Gulf 

of Mexico fisheries statistics was provided by Dr. Benny Gallaway and Dr. John Cole of L.G.L. 

Ecological Research Associates, Inc.
559

14.1INTRODUCTION

14.1.1 Overview

This document represents an internal Report for contract number: M08PC20038, issued by the 

U.S.Department of the Interior, Minerals Management Service “Deepwater Program: 

Exploration and Research of Northern Gulf of Mexico Deepwater Natural and Artificial 

Hard Bottom Habitats with Emphasis on Coral Communities: Reef, Rigs and Wrecks”. This 

report focuses on deepwater fishery practices in the Gulf of Mexico and potential for interactions 

with deepwater coral communities.

14.1.2 Overall Project Background

Over the last half century, offshore exploration for hydrocarbons in the northern Gulf of Mexico 

(GoM) has advanced from the bay and inner shelf to the continental slope-to-continental rise 

transition. Geophysical and geotechnical data collected in support of both exploration and 

production has been largely responsible for the foundation of our present understanding of slope 

geology. This database emphasizes the extremely complex geological framework of the northern 

Gulf’s continental slope and the surprisingly important role that the expulsion of subsurface fluids 

and gases has on shaping surficial geology and biology of the modern seafloor. Regional 

topography of the slope consists of basins, knolls, ridges, and mounds derived from the dynamic 

adjustments of salt to the introduction of large volumes of sediment over long time scales. 

Superimposed on this underlying topography is a smaller class of mounds, flows, and hard grounds 

that are the products of the transport of fluidized sediment, mineral-rich formation fluids, and 

hydrocarbons to the present sediment-water interface. The geologic response to the expulsion 

process is related both to the products being transported and the rate at which they arrive at the 

seafloor. Mud volcanoes and mudflows are typical of rapid flux settings where fluidized sediment 

is involved. Slow flux settings are mineral-prone. Authigenic carbonate mounds, hard grounds, 

crusts, and nodules are common to settings where hydrocarbons are involved. 

Recent manned submersible and ROV dives to the middle and lower continental slope confirm the 

existence of these hard substrates to the deepest parts of the slope. Direct observation and sampling 

of expulsion sites started in the mid-1980s on the upper slope. We now know from analysis of 

3D-seismic data and submersible-ROV dives that numerous expulsion sites with hard substrates 

provide habitat for deep water corals over the full depth range of the slope.

In the context of this study, deep hardground communities of the Gulf of Mexico comprise all of 

the biological communities inhabiting natural or artificial hard substrates, excluding the 

chemosynthetic seep communities. These communities consist of foundation species, those species 

that form large complex habitats at these sites, and the associated fauna ranging in size from large 

mobile fishes to microscopic meiofauna. The most prominent foundation species in these 

communities are the deep-water (“cold-water”) corals. The terms “deep-water corals” or “coldwater corals” include relatives of the tropical reef-forming scleractinian corals, but also refer to a 

variety of other cnidarian taxa including antipatharians (black corals), gorgonians (including 

bamboo corals), alcyonaceans (soft corals), and stylasterine hydrocorals. Other taxa, including 
560

anemones and sponges are also significant contributors to the biogenic framework of these deepwater reef systems. 

In the Gulf of Mexico, deep-water corals are commonly found on seep-related authigenic 

carbonates, but have also been observed on anthropogenic structures, ship wrecks and oil platforms 

in particular. The most common species of reef-forming deep-water coral in the Gulf of Mexico 

(GoM) is Lophelia pertusa (=prolifera). This species was first recovered in the late 1800s by the 

U.S. Coast Survey Steamer Blake.

Increasing industry activity in deepwater has resulted in the creation of numerous platforms in 

water depths exceeding 300 m. In areas where hard substrates are limiting, these platforms may 

significantly increase the potential range of corals and other hardground fauna. Growth of Lophelia 

pertusa has been noted on the Pompano platform in VK 989 (Schroeder et al. 2005). In addition, 

the Joliet platform in GC 184 near Bush Hill and the Neptune platform near the large L. pertusa

site in VK 826 are very likely to host coral populations. This study will focus on the exploration 

and characterization of these communities and examination of their potential connection to other 

coral populations and surrounding deep-water communities.

14.1.3 Objectives of the Project

A primary goal of this study is to obtain a robust predictive capability for the occurrence of rich 

cnidarian (primarily scleractinian coral) hard ground communities in the deep Gulf of Mexico. To 

achieve this long-term goal, this study will accomplish three interrelated and interdependent 

objectives:

1) Discover and describe new locations at greater than 300m depth in the GoM with extensive 

coral community development, particularly including Lophelia pertusa.

2) Gain a more comprehensive understanding of the fundamental processes that control the 

occurrence and distribution of Lophelia and other extensive coral communities at depths 

greater than 300 m in the GoM through both laboratory experiments and field data 

collection.

3) Document and understand the relations between coral communities on artificial and natural 

substrates with respect to community composition and function, phylogeographic and 

population genetics, and growth rates of the key cnidarian foundation fauna. 

4) As a supplement to the general program objectives listed above, this report will focus on 

the current status of deepwater fishing activities in the Gulf of Mexico to identify potential 

impacts of deepwater coral and other hard bottom communities.
561

14.2DEEPWATER FISHERIES IN THE GULF OF MEXICO

14.2.1 Background

The Minerals Management Service (MMS) has requested a review of commercial fishery activities 

that have the potential for negative interaction with deepwater coral communities, with primary 

emphasis on Lophelia or Madrepora in depths below 200 m. Few reports have documented the 

frequency and location of deepwater fishing practices in the Gulf of Mexico (GOM), particularly 

for the deep reef fish assemblage (primarily groupers, tilefishes and snappers) or have reported 

these practices to be relatively rare when compared to pelagic longlining (CSA 2002). 

The lack of a significant deepwater fishery in the GOM also makes this an ideal setting for the 

study of deepwater coral habitats in relatively pristine condition. In other regions of the world, the 

past and ongoing depletion of populations of deepwater fishes with long life spans such as rockfish 

(Sebastes spp.), orange roughy (Hoplostethus atlanticus), alfonsinos (Beryx spp.) and pelagic 

armourhead (Pseudopentaceros wheeleri) has resulted in significant damage to deepwater coral 

communities on Atlantic and Pacific seamounts and Lophelia reefs of the north Atlantic (Rogers 

1999, Koslow et al. 2001, Hall-Spencer 2002, Fossǻ 2002). In the southeastern U.S., trawling 

operations for rock shrimp and brown shrimp resulted in severe damage to the Oculina banks on 

the Atlantic coast of Florida (Reed et al. 2007). 

The deepest commercial trawl fisheries for bottom-dwelling fishes in the GOM remain on the 

continental shelf <200 m. However, the presence of potentially viable fishery species such as the 

red, white or longfin hake (Urophycis spp.), blackbelly rosefish (Heliocolenus dactylopterus) and 

numerous grenadiers (Macrouridae) in deeper waters suggests that there may be a limited fishery 

that has been largely undocumented, and that a larger commercial deepwater fishery in the GOM 

may yet develop (McEachran and Fechelm 1998). The golden crab (Chaceon fenneri) and deepsea 

red crab (C. quinquedens) support an active pot fishery in deepwater off the Atlantic coast of the 

U.S. with annual landings of several hundred thousand pounds (Steimle et al. 2001). Both species 

occur throughout the eastern and northern Gulf ( Lockhart et al. 1990, Waller et al 1995, Trigg et 

al. 1997). Limited golden crab fishing has historically occurred in the GOM; however crab fishing 

vessels have reportedly left the Gulf and the current potential of a focused fishery is marginal 

(NMFS 2004, S. Branstetter, pers. comm.). Therefore heavy deepwater crab pots do not currently 

appear to be a threat to deepwater corals, although future trapping efforts for both deepwater crabs 

and royal red shrimp could occur (GMFMC 2005a). Pelagic fishing practices such as longlining 

and midwater trawls can also impact deep sea corals due to entanglement with lost or abandoned 

fishing gear and accidental contact with the sea floor. Lost longlines have the potential to “ghost 

fish” for an extended period until the hooks are lost to corrosion. There is also a recent tendency 

of recreational or charter vessel fishers to “deep drop” on natural or artificial structures using 2-3 

lb lead weights, but this effort appears to be relatively rare and typically occurs at the shallow limit 

of deepwater coral occurrence.

14.2.2 Deepwater Coral Ecosystems

Deepwater or deep sea coral ecosystems (DCES) in the southeastern U.S. and northern GOM often 

support populations of deepwater groupers (snowy grouper, yellowedge grouper, warsaw 

grouper), tilefish, wreckfish, barrelfish, and alfonsinos that could potentially be targeted by 
562

longline or bandit reel fisheries (Reed et al. 2005, Reed et al. 2006, CSA 2007, Ross and Quattrini 

2007, Sulak 2008, Goldman and Sedberry in review) (Figure 14-1).

Finely branched corals, including Oculina and Lophelia, are vulnerable to entanglement in bottom 

longlines and may be broken and crushed by heavy weights and anchors as fishing gear is dragged 

across the seafloor upon retrieval, leading to colony breakage or lost equipment (Barnette 2001). 

Repeated trawling activities using heavy tickler chains, lead lines, and weighted doors can crush 

living colonies, remove the epibenthos, and reduce topographic complexity (Barnette 2001, Reed 

et al. 2007, Wells et al. 2008) (Figures 14-2, 14-3). Barnette (2006) observed extensive areas of 

entangled, overgrown, or abandoned longline gears in the vicinity of colonies of Oculina in the 

NW GOM, the result of commercial grouper fishing activities. Numerous deepwater gears 

deployed for deepwater groupers, golden crab, or royal red shrimp in the GOM could cause 

extensive damage to deepwater coral communities (Perry et al. 1995, Barnette 2001, CSA 2002, 

SAFMC 2009).

Previous reviews of deepwater fishing practices in the northern GOM indicate that the primary 

deepwater commercial fishery is pelagic longlining for tuna, followed by bottom longlining for 

deepwater groupers, snappers, and tilefishes (CSA 2002). Commercial deepwater trapping for 

golden crab and bottom trawling for royal red shrimp, two activities most likely to impact benthic 

communities, historically have been at much lower levels than bottom longlining, and 

geographically concentrated in south Florida and Alabama/Mississippi, respectively (Lockhart et 

al. 1990, Jones et al. 1994, Perry et al. 1995, Harper et al. 2000, CSA 2002). Current analysis will 

focus on identifying geographic trends of deepwater fishing activities and/or changes in effort for 

bottom fisheries associated with known hard bottom marine communities, including Lophelia

reefs.

14.2.3 Lophelia pertusa distribution

Schroeder et al. (2005) reviewed the distribution of Lophelia pertusa and Madrepora oculata to 

provide an assessment of the occurrence of these species in waters greater than 200 m in the GOM. 

Lophelia occurred at depths ranging from 343 to 878 m, with the majority of sites occurring 

between 450 and 650 m. Madrepora reef sites were reported from slightly deeper locations, up to 

937 m, and in more southerly locations (including sites below 25o N). Currently known Lophelia

locations occur north of 26o 30’ N, and are primarily distributed in a small region on the west 

Florida slope, the Mississippi-Alabama slope, and the Texas-Louisiana slope. While Lophelia

pertusa occurs to depths of over 800 m, the most well-developed and intensively studied reef sites 

occur at Viosca Knoll and Green Canyon Lease Blocks, at depths between 313 and 525 m (CSA 

2007, Cordes et al. 2008, Sulak 2008). In addition to natural deepwater coral assemblages, 

numerous Lophelia colonies have been observed on the Pompano platform in VK 989 at depths 

ranging from 204 to 385 m (Schroeder et al. 2005, J. Reed pers. comm., D. Weaver pers. observ.). 

To identify potential impacts of deepwater fishery gears on deep coral reef assemblages, including 

populations that colonize artificial structures (primarily production platforms and shipwrecks), we 

will focus on the review of existing fishery data occurring from 200 to 600 m.

14.2.4 Commercial Fishing Activities and Data Acquisition

The recent patterns in commercial deepwater fisheries (2000 to 2009) were reviewed to 

complement a previous assessment of bluewater/deepwater fisheries in the GOM (CSA 2002). 
563

The deepwater fishing industry was described from data provided by the NOAA Fisheries 

(previously known as the National Marine Fisheries Service or NMFS) labs from the reef fish and 

shrimp logbooks, and landings data reported from seafood dealers of individual Gulf states. 

Datasets for the deepwater (200 to 600 m) fishing activities were extracted for comparison to the 

shallow water (< 200 m) for reef fishes (deepwater groupers, tilefish, barrelfish, golden crab) to 

identify the relative importance of the deepwater fishery. Mandatory reporting of Gulf reef fish

and shrimp fishery information is collected by NOAA under the authority of the Magnuson Fishery 

Conservation and Management Act to effectively manage these fisheries. The reef fish logbook 

program has only recently included detailed information on depth of gear deployment, NMFS 

statistical grid, and specific location of gear sets. Data collected prior to 2005 often do not provide 

location or depth. The shrimp fishery was historically monitored through data collection by port 

agents who collected statistical information from vessel captains and port agents. The recent 

development of the electronic logbook system (ELB) has allowed more detailed records of shrimp 

trawling in the GOM, and has been installed on 450 of approximately 1,900 vessels operating in

the GOM, including vessels fishing for royal red shrimp (J. Nance, pers. comm., B. Gallaway pers.

comm.).

The reef fish logbook database, maintained by the NOAA’s Southeastern Science Center, Miami, 

only requires fisherman to report the numeric code of the NMFS statistical area, and not lat/long 

coordinates. Therefore data can only be assigned to statistical grids (individual grid cells cover 

one degree of longitude), but may be further limited to specific depth horizons of limited 

geographic area when depths are reported. Fishing effort and landings may be further extrapolated 

to occur in areas of natural hard bottom or artificial reef structures (deepwater platforms, 

shipwrecks), where many of the target species are known to associate. Statistical grid maps 

established by NMFS in the GOM are based on 21 individual cells established for the monitoring 

of the penaeid shrimp fishery, ranging from number 1 in the area of the Florida Keys/Dry Tortugas 

to 21 in Brownsville, TX (Figure 14-5). Grids no. 22 and 23 are located immediately south of the 

U.S./Mexico Border. The statistical grids continue from the Florida Keys northward along the east 

coast as four digit grid numbers, the first two digits designating latitude and the second two digits 

longitude (e.g. SAFMC grid 2481 is the equivalent of GOM grid no. 1 in the western Florida 

Keys). In the GOM, deepwater fishing activities occurring beyond the seaward boundary of the 

grid cell are included in the corresponding statistical area. Access to reef fish and shrimp logbook 

data are further limited when fewer than 3 vessels report landings per statistical grid, and the data 

are classified as confidential. Unfortunately, all three deepwater fisheries (bottom longlining for 

deepwater fishes, royal red shrimp trawling and deepwater crab traps) typically fall into this 

category, resulting in low spatial resolution of fishing activity or a complete lack of data.

14.2.5 Deepwater Fishery Species

Most fishes occurring in deepwater marine ecosystems are considered to be extremely vulnerable 

to overfishing based on life history traits and relatively low natural abundance. The American 

Fisheries Society (AFS) recognizes the increased vulnerability of many reef fishes, particularly 

those species dwelling in deepwater environments, due to their slow growth, long lifespan and late 

age of maturation (Coleman et al. 2000, Musick et al. 2000). Many deepwater groupers, wreckfish, 

and barrelfish enter the fishery at a relatively late age and can reach ages in excess of 60 years 

(Sedberry et al. 1993, 1999, Filer and Sedberry 2008, Shipp and Sedberry 2008). Deep-water 

marine fishes in general attain long lifespans (some up to 130 yrs), and an analysis of scorpaenid 
564

fishes indicates increased longevity with greater depth of occurrence (Caillet et al. 2001). Reefassociated fishes in the GOM and S.E. Atlantic also appear to follow this pattern. Deep-dwelling 

species are also subject to severe barotrauma upon capture, resulting in 100% mortality of 

undersized fish or bycatch species. Many species of reef fish form localized spawning 

aggregations that result in an even greater risk of overfishing. In addition, groupers first mature 

as female and as larger adults and later switch to male, resulting in the potential skewing of sex 

ratios through fisheries that target large individuals (Coleman et al. 2000, Koenig et al. 2000).

By definition, the GMFMC recognizes five species in the deepwater grouper (DWG) complex, 

including yellowedge grouper, misty grouper, warsaw grouper, snowy grouper, and speckled hind 

(NOAA 2009). For regulatory purposes scamp (Mycteroperca phenax) and tilefishes are also 

included in this category. For the purposes of this review, we will focus on the DWG species that 

make up the majority of the catch for the GOM below 200 m, as well as large fishes commonly 

associated with Lophelia reefs that could sustain a multi-species fishery. The following brief 

species descriptions have been described from Heemstra and Randall (1993), McEachran and 

Fechhelm (1998, 2005), Musick et al. (2000), CSA (2002) and Fishbase (www.fishbase.org). 

Snowy Grouper: Epinephelus niveatus

Geographic Distribution

The snowy grouper occurs along the outer continental shelf from North Carolina to southern Brazil 

in the western Atlantic, including the GOM, Bermuda, and Caribbean Sea.

Habitat and Biology

Snowy grouper occur in depths of 30 to 525 m, over rocky habitats or artificial structures, and are 

often associated with Lophelia reefs and other deep coral ecosystems. This species reaches a 

maximum length of 120 cm, and a weight of 30 kg. Maximum estimated age is 27 years (Heemstra 

and Randall 1993).

Fishery Importance

Snowy grouper are an important and abundant deep reef species in the GOM and western Atlantic, 

and are fished by commercial longlining and electric reels throughout the northern GOM. As with 

other deepwater groupers, this species is considered by the American Fisheries Society to be “at 

risk of extinction” due to its vulnerability to overfishing (Musick et al., 2000).

Warsaw Grouper: Epinephelus nigritus

Geographic Distribution

The warsaw grouper occurs along the outer continental shelf and upper continental slope from 

Massachusetts to Brazil in the western Atlantic, including the GOM.

Habitat and Biology

Warsaw grouper occur in depths of 50 to 400 m, over natural rocky habitats or artificial structures 

(Olander 1991, 1999). This species is the largest deep-dwelling grouper in the western Atlantic, 

reaches a maximum length of 230 cm, and a weight of 200 kg. Maximum estimated age is 40 

years.
565

Fishery Importance

The Warsaw grouper is incidental to fisheries targeting other deepwater species, as it typically 

occurs as solitary individuals or in small groups. As with other deepwater groupers, this species 

is considered by the American Fisheries Society to be “at risk of extinction” due to its vulnerability 

to overfishing (Musick et al., 2000).

Yellowedge Grouper: Epinephelus flavolimbatus

Geographic Distribution

The yellowedge grouper occurs along the outer continental shelf and upper continental slope from 

North Carolina to southern Brazil in the western Atlantic, including the GOM and Caribbean Sea.

Habitat and Biology

Yellowedge grouper occur in depths of 64 to 275 m, over rocky habitats or sand/clay bottoms. 

They are occasionally found in burrows or depressions in soft bottom sediments. This species 

reaches a maximum length of 110 cm, with males reaching larger sizes than females. Maximum 

estimated age is between 15 and 20 years (Bullock et al. 1996).

Fishery Importance

Yellowedge grouper are one of the most important and abundant deep reef species in the GOM 

and western Atlantic, and is fished by commercial longlining throughout the northern GOM. This 

species constitutes the majority of the deepwater grouper catch in the GOM. As with other 

deepwater groupers, this species is considered by the American Fisheries Society to be “at risk of 

extinction” due to its vulnerability to overfishing (Musick et al., 2000).

Tilefish: Lopholatilus chamaeleonticeps

Geographic Distribution

The tilefish occurs along the outer continental shelf and upper continental slope from the Scotian 

shelf, the entire eastern U.S. Coast, and the GOM to Campeche Bank.

Habitat and Biology

Tilefish occur in depths of 165 to 411 m in the GOM. They prefer soft bottom sediments where it 

constructs burrows. This species reaches a maximum length of 110 cm, and a weight of 18 kg 

(CSA 2002). 

Fishery Importance

Tilefish are an important deepwater species in the GOM and Atlantic coast, and is fished by 

commercial longlining and electric reels throughout the northern GOM. This species is vulnerable 

to overfishing, but not officially listed. Tilefish are often caught as part of a mixed species 

assemblage that included yellowedge and other deepwater groupers. The commercial quota of 

tilefish is set at 440,000 lbs.

Barrelfish: Hyperoglyphe perciformes

Geographic Distribution

The barrelfish occurs off the Atlantic coast of North America from Nova Scotia to the Florida 

Keys, and the eastern GOM. This species also occurs in the eastern North Atlantic and western 

Mediterranean.
566

Habitat and Biology

Barrelfish occur at depths between 200 to 800 m, over natural hard bottom or artificial habitats. 

This species reaches a maximum length of 104 cm, a weight of 12 kg, and can live up to 85 years 

(Filer and Sedberry 2008). Barrelfish enter the fishery between 12-16 yrs of age.

Fishery Importance

Barrelfish are primarily caught as bycatch in the deepwater wreckfish fishery of the Charleston 

Bump and Blake Plateau off the coast of the southeast United States. There also appears to be a 

limited fishery for this species in the GOM, possibly as bycatch in the longline fishery for tilefish, 

yellowedge and snowy groupers (Cass-Calay and Bahnick 2002), or specifically targeted on a 

limited basis by recreational or small charter vessels, particularly around deepwater petroleum 

platforms (Olander 2001).

Red Bream: Beryx decadactylus

Geographic Distribution

The red bream occurs worldwide in tropical and temperate latitudes.

Habitat and Biology

Red bream occur at depths between 110 to 1000 m, usually between 200 and 400 m over natural 

hard bottom, sand or muddy bottoms. This species reaches a maximum length of 100 cm, and a 

weight of 10 kg. 

Fishery Importance

The red bream is primarily caught as bycatch in the deepwater wreckfish fishery of the Charleston 

Bump off the coast of the southeast United States (Goldman and Sedberry In Review). This species 

has been observed during submersible surveys in associated with Lophelia coral mounds and other 

high profile hard bottom features (Reed et al. 2006, Ross and Quattrini 2007, D. Weaver personal

observation). Red bream are also a small component of a deepwater fishery worldwide that 

focuses on populations of the splendid alfonsino, B. splendens, on deep slopes and seamounts.

Splendid Alfonsino: Beryx splendens

Geographic Distribution

The splendid alfonsino occurs worldwide in tropical and temperate latitudes.

Habitat and Biology

Splendid alfonsinos occur at depths between 25 to 1240 m, and are commonly fished over 

seamounts in the Pacific at depths between 500 and 900 m. This species reaches a maximum 

length of 60 cm, and a weight of 2.5 kg, and reach an age of at least 17 years. 

Fishery Importance

The splendid alfonsino is caught as bycatch in the deepwater wreckfish fishery of the Charleston 

Bump off the coast of the southeast United States (Goldman and Sedberry In Review). There are 

directed deepwater longlining fisheries, trawl fisheries, and artisanal handline fisheries for this 

species throughout the world, particularly on seamounts and isolated islands bearing limited 

continental shelves (Vinnichenko 1997, Dürr and González 2002). This species does not appear 

to be abundant on Lophelia reefs in the GOM, but could be caught as bycatch for other deepwater 

species such as barrelfish.
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Wreckfish: Polyprion americanus

Geographic Distribution

Wreckfish have an antitropical distribution and are found in temperate waters of the northern and 

southern hemisphere, from Newfoundland to the Florida Keys, Southern Brazil to Argentina, and 

Bermuda. Wreckfish also occur throughout deepwater of the eastern North Atlantic including the 

Azores, Madeira, and the Mediterranean and in the Pacific waters of South Africa, Australia and 

New Zealand (Sedberry et al. 1999, Vaughn et al. 2001, Shipp and Sedberry 2008). Wreckfish 

have only recently been reported from the GOM (Sulak et al. 2008, Shipp and Sedberry 2008). 

Habitat and Biology

Adult wreckfish occur at depths between 42 to 1000 m, and are the primary species of the 

deepwater fishery at the Charleston Bump and Blake Plateau of the southeastern United States 

(Vaughn et al. 2001). This species reaches a maximum length of 146 cm, a weight of 47 kg, and 

reach an age of at least 31 years (Sedberry et al. 1999). 

Fishery Importance

Wreckfish fisheries of the southeastern United States and Bermuda are one of the few fishes 

supporting a deepwater fishery at Lophelia depths, and illustrate the typical problems associated 

with managing a deepwater fishery. An extensive wreckfish fishery developed on the Blake 

Plateau in the mid 1980s using vertical lines on hydraulic reels (Sedberry et al. 1999). Wreckfish 

landings exceeded 4 million pounds annually before dramatically declining in the mid 1990’s. The 

fishery has been successfully managed since 1990 under an Individual Transferable Quota (ITQ) 

system with an annual total quota set at 2 million pounds and a seasonal closure on the fishery 

during the January to April spawning period (Vaughn et al. 2001, Sedberry et al. 1999). The 

wreckfish fishery in Bermuda peaked at 5 metric tons (11,000 lbs) annually, and subsequently 

collapsed over a ten year period to a level that can no longer support a fishery (Sedberry et al. 

1999). Although significant populations of wreckfish are currently unknown from the GOM, they 

are relatively abundant on the Pourtales Terrace in the Straits of Florida (Reed et al. 2006, Weaver 

personal observation). A single individual caught off of Alabama was a large, gravid female 119 

cm in length, 31 kg in weight, and estimated to be 57 years old (Shipp and Sedberry 2008), 

indicating the possibility of a spawning population in the northern GOM. A review of yellowedge 

grouper handline trips in the GOM and associated fishes indicated 41 trips landing wreckfish out 

of a total of 118,000 logged trips (Cass-Calay and Bahnick 2002). 

Invertebrate Fishery Species

Deepwater invertebrate fishery species include royal red shrimp, golden crab, and red crab. The 

following brief species descriptions have been described from Bullis (1956), Anderson and 

Lindner (1971), Lockhart et al. (1990), Jones et al. (1994), Perry et al. (1995), Waller et al. (1995), 

CSA (2002), and Kilgour and Shirley (2008). 

Royal red shrimp: Pleoticus (Hymenopenaeus) robustus

Geographic Distribution

Royal red shrimp occur from Massachusetts to Central America and northern South America, 

including the GOM.
568

Habitat and Biology

Royal red shrimp prefer sand, clay or mud bottoms in water depths ranging from 180 to 730 m, 

with highest densities in the GOM at depths ranging between 350 and 500 m. Unlike shallowwater penaeid shrimp, which complete their life cycle in a single year, royal red shrimp have a 

lifespan of several years (Jones et al. 1994).

Fishery Importance

Primary fishing grounds for royal red shrimp occur over sand, silt, and muds of the Mississippi 

Delta and calcareous muds of the Dry Tortugas (Anderson and Lidner 1971). This species requires 

specialized equipment for capture and storage, including storage in brine and quicker freezing, 

contributing to the relatively limited fishery. Fishing gear requires larger vessels than shallow 

water shrimp species, and trawling gear includes a configuration that may include one, two, or four 

nets towed simultaneously behind two benthic sleds (Figure 14-3). Megalops or pinspeckled 

shrimp (Penaeopsis serrata) have also been reported in landings of royal red shrimp (Jones et al. 

1994). Ten other species of large deepwater shrimps are known to occur throughout the western 

Atlantic Ocean (Table 14-5), and could also contribute to regional fisheries.

Golden Crab: Chaceon fenneri

Geographic Distribution

Golden crabs occur on the upper continental slope from New England to Brazil, including the 

GOM. The species is reported to be rare in the northern Gulf, where red crabs are the dominant 

large crab on slope habitats.

Habitat and Biology

Golden crabs prefer soft or hard bottom in water depths ranging from 200 to 800 m, with primary 

depths in the GOM ranging between 300 and 500 m. They have been reported to occur on natural 

hard bottom among sea fans and other sessile invertebrates.

Fishery Importance

Primary fishing grounds for golden crab occur along the east coast of the U.S. from North Carolina 

to the Florida Keys. Demand for golden crab is variable, as this species is mainly marketed as a 

substitute for snow crab. Gulf Coast fisheries were historically limited to the West Florida slope 

south of Tampa, FL, but currently appear to be nonexistent in the GOM. Commercial fishing for 

golden crab is currently unregulated, although they have been recognized as a potential fishery 

species and may be taken by trap only. 

Deepsea Red Crab: Chaceon quinquedens

Geographic Distribution

Deepsea red crabs occur on the upper continental slope from New England to Brazil, including the 

GOM. This species is the dominant large crab on slope habitats in the northern GOM (Waller et 

al. 1995, Kilgour and Shirley 2008).

Habitat and Biology

Deepsea red crabs prefer silty bottom habitats in water depths ranging from 300 to 2000 m, with 

primary depths in the GOM ranging between 670 and 1,000 m. Minimum depths are reported to 

be 860 m to the west of the Mississippi River delta and 677 m east of the river, deeper than most 

of the well-developed Lophelia sites in the northern GOM.
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Fishery Importance

Primary fishing grounds for red crab occur along the East coast of the U.S. north of Cape Hatteras, 

N.C., in depths of 400 to 800 m. Red crab populations have been reported to reach densities 

capable of supporting a fishery in the northern GOM but this species is not currently exploited, 

and the increased depth of occurrence may make it economically unfeasible for a fishery to 

develop. As a result this fishery is unregulated.

14.2.6 Historical Development of the Deepwater Grouper and Tilefish Fishery

The fishery for shallow water snappers and groupers in the GOM has been well established since 

the 1870’s, expanding shortly after the end of the Civil War (Jarvis 1935, Prytherch 1983). The 

availability of natural ice, delivered by schooners from Maine, for shipping food led the 

development of a commercial fishery in Pensacola, FL, (Prytherch 1983). Fish were initially held 

onboard in live wells and later packed in ice at sea. By the 1920s over 85 vessels were engaged in 

the reef fish fishery throughout the GOM to depths of 170 m, the harvest of red snapper and 

groupers reached almost 15 million pounds annually, and the fishery showed signs of overfishing 

(Jarvis 1935). Beginning in the 1930s, investigations by the U.S. Bureau of Fisheries focused on 

the development of alternative fishing methods at different depths across the continental shelf, 

including experimental longlines and fish traps, to improve the efficiency of the fishery. The 

results of longline experiments indicated that this was a promising and effective method for the 

landing of groupers. Research cruises conducting exploratory bottom longline fishing were 

conducted in the 1950’s and 1960’s, and resulted in high catch rates of tilefish, which were not 

commercially important species at that time (CSA, 2002).

Early use of handlines was replaced with by vertical lines passing through a rail-mounted davit 

with an attached motor, named a “One Arm Bandit” or “Bandit Rig” (Prytherch 1983, CSA 2002). 

Bandit rig fishing became common through the Gulf, and was supplemented with longlining on a 

commercial basis beginning in the late 1970’s. Bottom longlining activity reached a peak in the 

early 90’s, although most vessels were also equipped with bandit rigs (Prytherch 1983). The rapid 

development of bottom longline fishing in the Gulf caused concern over heavy impacts to the 

grouper and snapper fishery, coupled with the easy conversion of shrimp vessels to bottom 

longliners and rapid entry into the fishery in years where demand for shrimp was low (Prytherch 

1983).

An analysis of reef fish longlining practices was later conducted by the NMFS in the 1960’s on 

fishing vessels to depths of 340 m (Prytherch 1983) to investigate gears and effectiveness of 

harvest for different species, and provide information to the Gulf of Mexico Fishery Management 

Council for the development of the first Reef Fish Management Plan. The reef fish management 

plan has repeatedly been amended to prevent the overfishing of many species, including groupers 

and red snapper. The initial quota was set at 1.8 million pounds, and was twice reduced to the 

current quota of 1.02 million pounds.

14.2.7 Current status of the Deepwater Reef Fish Fishery

Large predatory reef fishes in the GOM, including groupers and snappers, are highly susceptible 

to overfishing, and populations have dramatically declined in both GOM and Atlantic shelf-edge 

reef sites (Coleman et al. 2000, Koenig et al., 2000, Reed et al. 2007). Fishing on hard bottom reef 
570

ecosystems below approximately 50 m results in elevated mortality of juveniles and undersized 

adults due to barotrauma, further complicating management of the fishery. At greater depths, 

including Lophelia coral sites, reported populations of deepwater groupers and other fishery 

species (wreckfish, barrelfish, alfonsinos) are typically small (Reed et al. 2005, Sulak 2008), and 

would be vulnerable to depletion by very few fishing vessels. Submersible and remotely operated 

vehicle surveys also have documented lost longlines between 200 and 500 m, indicating fishing 

activity on Lophelia communities.

 

A preliminary analysis of Lophelia distribution and the NOAA reef fish logbook data indicates 

relatively low deepwater (200 to 600 m) fishing activity in the management grid areas with known 

Lophelia reefs, particularly those in the northern GOM (Figures 14-5 – 14-7). Deepwater reef 

fish effort appears to be concentrated along the west Florida shelf, in statistical grids 1-9. Recent 

(2007 to 2009) patterns indicated increased fishing activity in depths of less than 200 m in grids 

10 and 11, the region of Viosca Knoll reef sites, but current efforts below 200 m appears to be 

relatively low or are confidential in nature (Figure 14-11). The current pattern of fishing effort 

appears to be concentrated in the region of the west Florida slope Lophelia sites and the Florida 

Keys (Figure 14-11).

Landings of deepwater groupers and tilefish appear to be relatively stable during the last 20 years 

(Figures 14-12 - 14-14). A gradual increase in number of reef fish trips that landed these species 

in the GOM was reported from 1990 to 2003 (Figure 14-12). The number of trips declined between 

2004 and 2009, likely due to early closures in the fishery, rising fuel costs, and the implementation 

of Secretarial Amendment 1, which established a rebuilding plan and reduced commercial quotas 

for shallow and deepwater groupers (decreasing the deepwater grouper quota from 1.35 to 1.02 

million lbs gutted weight). While the number of trips during this period was reduced, reported 

landings per trip increased slightly, for both total landings of reef fishes and deepwater species 

(Figure 14-12, 14-15), and in 2009 was the highest for the entire 1990-2009 period. State reported 

landings display a slightly different pattern, with peaks in deepwater grouper landings in 2000 and 

2003, and relatively constant landings of ~ 1.2 million pounds in other years from 2001 to 2009. 

Deepwater fisheries in the GOM are limited in both number of vessels engaged in the fishery and 

number of trips taken annually. Early closure of the 2009 deepwater grouper and tilefish fishery 

in the GOM and subsequent implementation of an Individual Fishery Quota (IFQ) system reflects 

ongoing difficulties with management of the resource and a need for more restrictive management 

actions to regulate the fishery (GMFMC 2008, NMFS 2009a, b, NOAA 2009). During the 2009 

season, deepwater grouper fisheries were closed on June 27 and the tilefish fishery closed on May 

15th due to the early harvest of the commercial quota. Reef fish trips for deepwater groupers, 

snappers, and tilefish are now of limited entry and managed through an IFQ system, established 

on August 31st, 2009 by the NOAA Fisheries Service. Individual IFQ allocations will eliminate 

the need for early closure of the fishery and improved records of fishing activity, and the 2010 

commercial quota remained set at 1.02 million pounds. NOAA is currently considering, through 

Amendment 31 to the reef fish FMP, the reduction in number of commercial longline vessels in 

the eastern GOM through a longline endorsement, and also limiting the number of total hooks on 

vessels to 1,000 with a maximum of 750 rigged or fished at a time. The possible shift in effort to 

deepwater longlining could be hindered by the IFQ system.
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14.2.8 History of the Deepwater Shrimp Fishery

The commercial shrimp industry began in the early 1800s along the southeastern U.S. Coast, using 

cast nets and seines, and shrimping began in Galveston in the 1830s. Sailboats were positioned in 

tidal inlets to harvest shrimp as they migrated out of estuaries into the GOM. Shrimp were salted 

and shipped in barrels to distant markets. In 1910, shrimp were shipped in ice or frozen and sent 

to cities as far as Chicago and New York. During World War 1, gasoline powered vessels and 

otter trawls were used and international markets developed with Japan, as well as domestic markets 

with other Gulf coast states. Shrimping activity further increased after World War II through the 

1970s. In recent years high fuel costs and the import of farmed shrimp has led to fluctuations in 

the market, but the fishery remains one of the most valuable in the United States, in terms of 

economic value and weight (Table 14-6).

As with bottom longlining, deepwater exploratory trawling by the Bureau of Commercial 

Fisheries, Pascagoula lab identified exploitable populations of royal red shrimp in the 1950’s in 

300 to 800 m (Bullis 1956, CSA 2002). Commercial fishing for royal red shrimp began in 1960 

(Figure 14-9), but landings have been very small compared to the shallow water penaeid shrimp 

fishery. Fewer than 25 vessels have fished for royal red shrimp in any given year, compared to an 

estimated 20,000 shrimp vessels operating in state or federal waters for brown, white and pink 

shrimp. `

14.2.9 Current status of the Deepwater Invertebrate Fishery

The red and golden crab fishery is managed by fishery management plans in North and South 

Atlantic Coast regions, but management plans are lacking for the GOM (Kilgour and Shirley 2008, 

S. Branstetter personal communication). The initial development of a management plan to avoid 

potential conflicts with the royal red shrimp trawl fishery was discontinued when the value of the 

fishery was considered to be too low (GMFMC 1995, 2001, 2005). Despite suggestions of a viable 

fishery for red and golden crab in the literature, there appears to be no active vessels fishing for 

either species in the GOM. Only three reports of catch of golden crab were reported in the NMFS 

fishery logbook databases from 1990 to 2009, although there are reports of over 220,000 pounds 

per year harvested in the GOM Commercial fisheries (Table 14-6). These landing may occur as 

bycatch during the royal red shrimp fishery. Population densities of golden crab and deepsea red 

crab appear to be too low for an economically viable entry into the fishery (S. Branstetter, personal 

communication). 

The royal red shrimp trawl fishery currently appears to be limited to three full time vessels in the 

GOM with up to sixteen vessels historically participating on a part-time basis in recent years 

(Jones et al. 1993, GMFMC 2001, GMFMC 2005, Stiles et al. 2007) (Table 14-1). Current 

trawling activity primarily occurs on the west Florida slope and the area surrounding the DeSoto 

Canyon, including the Viosca Knoll region (Stiles 2008, J. Nance, NOAA Fisheries, personal 

communication) (Figures 14-8, 14-10). Fishing historically has concentrated in NMFS Statistical 

Grid 2, 4 and 5 off the west coast of Florida, and grids 9-11 in the northeastern GOM. Recent 

fishing activity is concentrated in the Dry Tortugas and northern GOM around the Mississippi 

Delta and DeSoto Canyon, in both number of trips and landings (Figure 14-10). Trawling for 

royal red shrimp occurs in the depth range of known Lophelia communities, and could have 

considerable impacts on the region of the central west Florida slope and northern Gulf where 
572

deep coral reefs occur. Unfortunately the exact locations of trawls in this fishery are classified as 

confidential, and a more detailed analysis of fishing effort will have to be made to identify 

potential interaction with deepwater coral sites. 

The following data are based on 520 tows from 16 ELB trips where royal red shrimp were the 

primary catch: The total catches were 512,948 pounds of tails equivalent of royal red shrimp. 

Mean tow time: 6.71 hours, standard error of tow time: 0.089 hours (J. Cole, L.G.L. pers.

comm.). Royal red shrimp boats are typically larger than shallow water vessels, in excess of 40 

m in length, to accommodate extra cable for deep trawling. Fishermen typically deploy the quad 

net arrangement common in the shallow penaeid shrimp fisheries (B. Gallaway, LGL, pers. 

comm.).

Table 14-1.

Number of vessels and trips for royal shrimp in the Gulf of Mexico, 2004-2008, from 

the NMFS logbook system SEFSC.

Year Unloaded Vessels Dedicated Vessels Unique Triptickets Unique Trips

2004 16 12 44 56

2005 11 4 27 31

2006 6 0 25 25

2007 8 0 30 30

2008 8 3 24 27

Impacts of fuel costs on the shallow water shrimp fleet and fluctuating imports of farmed shrimp 

could lead to increased levels of activity in the royal red shrimp fishery by dedicated vessels 

(GMFMC 2005). The GMFMC and NOAA Fisheries have also considered increasing the total 

allowable catch (TAC) above the current level of 392,000 lbs, an action that could stimulate 

conversion to the fishery. Historically the overall harvest has been relatively low, has declined in 

recent years and is at approximately 50% of the quota (Figure 14-4).

14.2.10 Oculina Banks Ecosystem Impacts

While current deepwater fisheries in the GOM appear to be conducted by a limited number of 

vessels in fairly restricted geographic areas, the potential impact of commercial longline and trawl 

fisheries to deep coral communities have been well documented in the Oculina ecosystems along 

the east coast of Florida (Koenig et al. 2000, Reed et al. 2007). Heavy commercial and recreational 

fishing pressure resulted in removal of large populations of adult groupers, and resulted in a drastic 

change in ecosystem structure of the resident fish communities. Commercial trawling for rock 

shrimp and brown shrimp in unprotected areas resulted in a nearly complete removal of living 

coral, with live coral remaining only in areas protected as a habitat area of particular concern 

(HAPC) established in 1984 (Reed et al. 2007, Stiles et al. 2007). 

Because of the potential for future expansion of deepwater shrimp and crab fisheries, and possible 

targeting of high profile coral banks for deepwater fishes, the establishment of deepwater coral 

HAPCs for future protection of these areas is warranted. Currently regulated HAPC’s in the GOM 
573

are limited to the shelf edge reefs and banks of the northwestern Gulf and West Florida Shelf 

(GMFMC 2005), and reef fish Essential Fish Habitat (EFH) is only considered to depths of 200 

m. The only exception is the Tortugas South Ecological Reserve of the Florida Keys National 

Marine Sanctuary, which extends from depths of 30 to 1000 m, and protects known spawning 

habitat for reef fishes on Riley’s Hump coral reef ecosystem and a number of deepwater groupers 

(Weaver et al. 2006). An extensive hard bottom community occurs between depths of 80 and 145 

m thoughout the reserve, but no deepwater coral ecosystems are known to occur below 200 m. 

Although the EFH Amendment to the Reef Fish Management plan does not consider habitat below 

200 m, many species listed in the amendment occur below these depths on deepwater coral 

ecosystems (Table 14-7).

14.2.11 Coral Habitat HAPCs in the South Atlantic

The South Atlantic Fishery Management Council has identified deep sea coral ecosystems (DSCE) 

off the east coast of the U.S. as Coral Habitat Areas of Particular Concern (CHAPCs), and 

recommended designation of four areas (Figure 14-16) to protect against destructive impacts of 

trawling for royal red shrimp and benthic finfish (SAFMC 2009). Approved by the SAFMC in 

September, 2009, the action is part of the Comprehensive Ecosystem-Based Amendment 1, is 

awaiting final approval by the Secretary of Commerce, and expected to be effective in early 2010. 

The council has justified this action to protect potential fisheries and the discovery of 

pharmaceutical compounds from the diverse deepwater reef fauna in depths of 400 to 700 m, while 

maintaining deepwater fisheries in the region. Council members worked closely with golden crab 

and royal red shrimp fisherman to insure both protection of deepwater coral areas and continuation 

of the deepwater fisheries by establishing both “Allowable Golden Crab Fishing Areas” and 

“Shrimp Fishery Access Areas” within two of the proposed HAPCs (SAFMC 2009). 

Designation of CHAPC zones for known Lophelia sites in the GOM would provide the equivalent 

protection for these ecosystems, and the collaborative process followed by the SAFMC serves as 

a guideline for the GMFMC, MMS, and collaborating agencies.

14.3SUMMARY

1. Deepwater fisheries in the GOM are limited with respect to number of vessels engaged in 

the fishery and number of trips taken annually. Regulatory closures also constrain the 

fishery. During the 2009 season, deepwater grouper fisheries were closed on June 27 and 

the tilefish fishery closed on May 15th due to the early harvest of the commercial quota. 

Reef fish trips for deepwater groupers, snappers, and tilefish are now of limited entry and 

managed through an Individual Fishing Quota (IFQ) system, established on August 31st, 

2009 by the NOAA Fisheries Service. Individual IFQ allocations will eliminate the need 

for early closure of the fishery and improve regulation of the industry. An amendment 

under review to reduce shallow water bottom longlining activity in the eastern Gulf could 

cause vessels to shift to deeper waters, but an increase in the overall harvest of deepwater 

groupers and tilefish will be prevented by the IFQ system. It is possible that vessels could 

target barrelfish on Lophelia reefs, as landings are unregulated for this species, to increase 

the overall catch.
574

2. The spatial distribution of deepwater grouper and tilefish trips primarily occurs on the west 

Florida shelf, based on the non-confidential component of the reef fish log books. 

Confidential records include between 30 and 100 trips per year that occur between the 

Mississippi River Delta and Brownsville. Based on the percent of landings, most of these 

trips appear to target yellowedge grouper at depths less than 300 m (maximum reported 

depth for this species is 275 m), and to a lesser extent snowy and warsaw groupers. Few 

vessels appear to target deeper communities where Lophelia reefs occur, based on the low 

catch of barrelfish, which regularly occurs as bycatch in the deepwater grouper fishery. 

(Note: A breakdown of reef fish trips and landings by 100 m depth horizons will be 

provided by J. Bennett, NOAA Fisheries, for inclusion in a future draft).

3. Royal red shrimp fisheries have historically been conducted by 3 to 12 full time vessels in 

the GOM per year, and primarily in the areas of the Dry Tortugas and east of the Mississippi 

Delta. Electronic logbook records for 2008 indicate trawling activity in the vicinity of 

known Lophelia reefs, most likely by a single vessel. Recent trends in the fishery show a 

decline in fishing effort and harvest, but the fishery for this species has been highly variable 

over the last 50 years. NOAA Fisheries has considered raising the quota to accommodate 

expansion of the fishery under favorable market conditions, and low demand for or 

restrictions on shallow penaeid shrimp species could shift efforts to deeper waters. 

Because of the restricted depth range of royal red trawling between ~350 and 500 m, this 

activity could have significant effects on known Lophelia communities.

4. The focused golden and deepsea red crab fishery currently appears to be extremely limited 

or nonexistent, other than as possible bycatch in the royal red shrimp fishery. NOAA 

Fisheries has limited gear to traps for deepwater geryonid crabs, but the fishery is otherwise 

unregulated. Although golden crab populations appear to be south of the main area of 

known Lophelia beds, and red crabs in deeper slope waters of the northern Gulf, 

exploratory trap fishing for these species could significantly damage deepwater corals.

5. The South Atlantic Fishery Management Council has identified deep sea coral ecosystems 

(DSCE) of the east coast of the U.S. as Habitat Areas of Particular Concern (HAPCs), and 

recommended designation of four areas to protect against potentially destructive impacts 

of trawling for royal red shrimp and benthic finfish. The council has justified this action 

to protect potential fisheries and the discovery of pharmaceutical compounds from the 

diverse deepwater reef fauna. Designation of DSCE areas for the GOM therefore has 

precedent as a management option for protection of Lophelia pertusa and other deepwater 

coral ecosystems.
575

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584

Figure 14-1. A typical bottom longline used for reef fish in the Gulf of Mexico (from CSA 2002).
585

Figure 14-2. Configuration of a standard shrimp trawl used for shallow water penaeid shrimp in the Gulf of Mexico. Image courtesy 

NOAA Fisheries.
586

Figure 14-3. . Diagram of shrimp trawl configuration typically used for shallow water penaeid shrimp in the Gulf of Mexico. 

This arrangement is also used in deepwater trawling for royal red shrimp. Image courtesy NOAA Fisheries.
587

Figure 14-4. Historical landings for royal red shrimp in the Gulf of Mexico.

0

50,000

100,000

150,000

200,000

250,000

300,000

350,000

400,000

1960196219641966196819701972197419761978198019821984198619881990199219941996199820002002200420062008

Year

Pounds (Tail Weight)
588

Figure 14-5. NMFS statistical areas for the Gulf of Mexico, grids 1 to 21.
589

Figure 14-6. Known Lophelia pertusa sites in the Gulf of Mexico, with 200 and 600 m contours. Open circles represent sites 

discussed in Shroeder et al. 2005. Open triangles are sites visited during Lophelia II cruises
590

Figure 14-7. Known Lophelia pertusa sites in the Gulf of Mexico with NMFS grid overlay.
591

Figure 14-8. Electronic Logbook (ELB) records of shrimp trawl locations for the Gulf of Mexico made in 2008. The deep locations 

suggests trawling for royal red shrimp in the vicinity of known Lophelia coral sites. Data from Gallaway et al. 2009.
592

Figure 14-9. Royal red shrimp trawling grounds in the vicinity of known Lophelia coral sites. From Bullis 1956.
593

Figure 14-10. Summary of landings and trips for royal red shrimp, 2000-2008, by NMFS 

Statistical Grid. Data provided by J. Nance, NOAA Fisheries Galveston Lab. Highest 

activity occurs in the Dry Tortugas (1) and Mississippi Delta/DeSoto Canyon (10) 

regions.

Tail Weight (pounds)

NMFS Statistical Grid

Royal Red Shrimp Landings from 2000 -2008 by NMFS Statistical Grid

Number of trips

NMFS Statistical Grid

Royal Red Trips from 200 - 2008 by NMFS Statistical Grid
594

Figure 14-11. Summary of trips targeting deepwater reef fishes, per NMFS statistical grid 2007-

2009, from the non-confidential portion of the reef fish logbooks. Number of Trips

NMFS Statistical Grid

2009

0-200m

200-600 m

Number of Trips

NMFS Statistical Grid 

2008

0 to 200 m

200 to 600 m

Number of Trips

NMFS Statistical Grid

2007

0 to 200 m

200 to 600 m
595

Figure 14-12. Summary of trips targeting deepwater reef fishes from the reef fish log book (top), 

and catch in pounds per trip, 1990-2009 summed across the Gulf of Mexico.

Number of Trips

Year

Reef Fish Trips in GOM from Logbook Database

confidential

non-conficential

Landings ( Pounds)

Year

Landings per trip

Total Reef Fish

DWG/Tilefish/Barrelfish
596

Table 14-2.

Effort in miles of line and number of hooks from reef fish longline records showing depth information and landing selected 

species of deepwater grouper and tilefish. Data are from the NMFS logbook system, SEFSC.

YEAR Depth (m) Max (mi) Min (mi) Avg (mi) Mode (mi)

Max no. 

hooks

Min no. 

hooks

Ave no. 

hooks Mode hooks

No. 

records

2004 0-200m 7 2 4.81 2 1000 200 687.5 1000 8

2005 0-200m 26 1 6.32 4 2500 100 1018.7 1000 308

2006 0-200m 20 1 6.23 5 2500 100 1151.8 1500 456

2007 0-200m 24 1 6.09 5 3000 50 1177.29 1000 329

2008 0-200m 15 1 6.1 5 3000 5 977.13 500 379

2009 0-200m 17 1 5.26 6 3000 60 911.73 1000 356

2005 201-600m 18 1.5 6.17 5 3500 300 1075 500 60

2006 201-600m 16 1 6.99 5 2200 12 1132.99 1500 91

2007 201-600m 16 1 6.9 5 2500 50 1197.63 1200 158

2008 201-600m 14 1 6.98 10 3000 16 1224.1 1000 149

2009 201-600m 15 2.5 6.99 5 3000 200 1185.78 1000 147
597

Figure 14-13. Landings in pounds for deepwater groupers (top) and tilefish (bottom), total catch 

from 2000 through 2009, based on reported state landings summed across the Gulf of 

Mexico.

Landings (pounds)

Year

Tilefish Landings (State)

2000

Landings (Pounds)

Year

Total Deepwater Grouper Landings (State)

warsaw grouper

snowy grouper

yellowedge
598

Figure 14-14. Landings in pounds for select deepwater species, total catch from 2000 through 2009, based on reported state landings 

summed across the Gulf of Mexico.

Year

Barrelfish 

confidential

non-confidential

Snowy Grouper

confidential

non-confidential

Warsaw Grouper

confidential

non-confidential

Yellowedge Grouper

confidential

non-confidential
599

Figure 14-15. Summary of deepwater grouper landings in pounds per trip, (top), and total 

barrelfish landings (bottom) summed across the Gulf of Mexico for years 1990-2009.

Landings (pounds)

Year

Deepwater Groupers - Landings per trip

warsaw grouper

snowy grouper

yellowedge grouper

Landings (pounds)

Year

GOM barrelfish landings

1990
600

Figure 14-16. Habitat Areas of Particular Concern (HAPCs) designated in the Comprehensive 

Ecosystem-Based Amendment 1, by the South Atlantic Fisheries Management Council 

in September 2009, pending final approval by the Secretary of Commerce. From 

SAFMC 2009.
601

Table 14-3.

Lophelia sites known from the Gulf of Mexico. Sites no. 1 to 24 taken from Schroeder et al. 

2005. Sites 25 to 42 visited during Lophelia II project cruises.

Site Species Area Lat Long Depth_m Source

1 Lophelia pertusa W. Florida Slope 26.500000 -84.833333 640 (Cairns, 2000)

1 Madrepora oculata W. Florida Slope 26.500000 -84.833333 640 (Cairns, 2000)

2 Lophelia pertusa DeSoto Canyon 29.233333 -87.000000 878 (Cairns, 1979)

3 Lophelia pertusa Mississippi Canyon 29.158333 -88.016667 430-520 (Schroeder,2002)

4 Lophelia pertusa Mississippi Canyon 29.200000 -88.050000 457-549 (Cairns, 1979)

5 Lophelia pertusa** Mississippi Canyon 29.083333 -88.316667 421-512 (Moore and Bullis, 1960)

6 Lophelia pertusa Mississippi Canyon 29.166667 -88.333333 519 (Cairns, 2000)

7 Lophelia pertusa Mississippi Canyon 29.106667 -88.381667 343 NOAA RON BROWN

8 Lophelia pertusa Mississippi Canyon 28.066667 -89.716667 616-630 NOAA RON BROWN

8 Madrepora oculata Mississippi Canyon 28.066667 -89.716667 616-630 NOAA RON BROWN

9 Madrepora oculata Mississippi Canyon 28.028333 -89.726667 650 JSL3340

10 Lophelia pertusa Mississippi Canyon 27.893333 -90.118333 635 Boland 1986

11 Madrepora oculata Green Canyon 27.733333 -91.045000 720 JSL4398

12 Lophelia pertusa Green Canyon 27.716667 -91.266667 N/A (Cairns, 2000)

13 Lophelia pertusa Green Canyon 27.781667 -91.506667 540-570 (MacDonald et al, 1989)

14 Lophelia pertusa Green Canyon 27.705000 -91.548333 543-783 (Viada and Cairns, 1987)

15 Madrepora oculata Green Canyon 27.783333 -91.550000 300 JSL2064

16 Madrepora oculata Green Canyon 27.783333 -91.550000 524-539 JSL 4577

16 Lophelia pertusa Green Canyon 27.596667 -91.826667 524-539 NOAA RON BROWN

17 Madrepora oculata Garden Banks 27.533333 -93.033333 732-823 (Cairns, 1979)

18 Madrepora oculata Tuxpan 23.916667 -97.000000 937 (Cairns, 1979)

19 Madrepora oculata Tuxpan 23.500000 -97.183333 732 NMNH Database

20 Madrepora oculata Yucatan 24.366667 -87.783333 549 NMNH Database

21 Madrepora oculata Yucatan 23.300000 -86.550000 914 (Cairns, 1979)

22 Madrepora oculata Yucatan 23.183333 -86.466667 914 (Cairns, 1979)

23 Lophelia pertusa W. Florida Slope 26.333525 -84.750075 428-466 HBOI-Reed

24 Lophelia pertusa B.P. Pompano 28.973033 -88.625983 204-292 HBOI-Reed

25 Lophelia pertusa VK826 29.142 -88.037833 610 Lophelia II_Cruise 2

26 Lophelia pertusa GC140 27.786 -91.703333 330 Lophelia II_Cruise 2

27 Lophelia pertusa GB201 27.761167 -92.729833 na Lophelia II_Cruise 2

28 Lophelia pertusa EB478 27.3895 -93.600167 627 Lophelia II_Cruise 2

29 Lophelia pertusa GB535 27.498167 -94.065667 nr Lophelia II_Cruise 2

30 Lophelia pertusa GC234 27.7355 -91.263833 555 Lophelia II_Cruise 2

31 Lophelia pertusa GC246 27.711333 -90.676 755 Lophelia II_Cruise 2

32 Lophelia pertusa GC535 27.578333 -91.8355 nr Lophelia II_Cruise 2

33 Lophelia pertusa MC751 28.154 -89.738 nr Lophelia II_Cruise 2

34 Lophelia pertusa AT47 27.893333 -89.762333 nr Lophelia II_Cruise 2

35 Lophelia pertusa MC885 28.0825 -89.7185 nr Lophelia II_Cruise 2

36 Lophelia pertusa VK906 29.037833 -88.393333 500 Lophelia II_Cruise 2

37 Lophelia pertusa EW1009 27.991667 -90.00929 Lophelia II_Cruise 2

38 Lophelia pertusa MC539 28.436667 -89.443333 Lophelia II_Cruise 2

39 Lophelia pertusa EW1008 27.991667 -90.081667 EW Shipwreck

40 Lophelia pertusa GC245 27.743333 -90.725 Green Lantern Shipwreck

41 Lophelia pertusa MC497 28.478333 -89.345 Gulfpenn Shipwreck

42 Lophelia pertusa MC796 28.17 -89.781667 Gulfoil Shipwreck
602

Table 14-4.

Fishes with potential commercial value associated with deep hard bottom or coral communities below 200 m.

Family Name Common Name Depth Reported (m) Source

Carcharhinidae

Carcharhinus falciformis silky shark 335-522 Reed et al. 2006

Carcharhinus signatus night shark Cass-Calay and Bahnick 2002 

Carcharhinus obscurus dusky shark Cass-Calay and Bahnick 2002 

Lamnidae

Isurus paucus longfin mako Cass-Calay and Bahnick 2002 

Alopiidae

Alopias superciliosus bigeye thresher 0 - 500 m Weaver, pers. obs.

Squalidae

Squalus cubensis Cuban dogfish 267-525 Reed et al. 2006, Matlock et al. 1990

Triakidae

Mustelus sp. dogfish Reed et al. 2006

Congridae

Conger oceanicus conger eel Reed et al. 2006

Macrouridae

Nezumia sp. grenadiers 322-752 Reed et al. 2006

Moridae

Laemonema barbatulum shortbeard codling 521 Reed et al. 2006

Laemonema melanurum codling 186-770 Reed et al. 2006

Phycidae

Phycis spp. hakes 557-767 Reed et al. 2006

Urophycis floridana southern hake 267-311 Reed et al. 2006, Matlock et al. 1990

Urophycis cirrata gulf hake 267-311 Matlock et al. 1990

Urophycis chuss red hake Matlock et al. 1990

Polymixidae

Polymixia lowei beardfish 267-414 Reed et al. 2006, Matlock et al. 1990

Berycidae

Beryx decadactylus red bream 287-671 Reed et al. 2006

Trachichthyidae

Gephyroberyx darwinii big roughy 392-518 Reed et al. 2006

Centrolophidae

Hyperoglyphe perciformis barrelfish 267-311 Reed et al. 2006, Matlock et al. 1990

Serranidae

Antias nicholsi yellowfin bass 179-283 Reed et al. 2006

Epinephelus flavolimbatus yellowedge grouper 267-311 Matlock et al. 1990

Epinephelus niveatus snowy grouper 70-308 Reed et al. 2006

Epinephelus mystcinus misty grouper Cass-Calay and Bahnick 2002 

Hemanthias leptus longfin bass 267-311 Matlock et al. 1990

Polyprionidae

Polyprion americanus wreckfish 283-693 Reed et al. 2006
603

Table 14-4 Continued. 

Family Name Common Name Depth Reported (m) Source

Lujanidae

Etelis oculatus queen snapper Cass-Calay and Bahnick 2002 

Lutjanus buccanella blackfin snapper Cass-Calay and Bahnick 2002 

Lutjanus vivanus silk snapper Cass-Calay and Bahnick 2002 

Lophiidae

Lophiodes reticulatus reticulate goosefish 267-311 Matlock et al. 1990

Malacanthidae

Caulolatilus microps blueline tilefish Reed et al. 2006

Scorpaenidae

Helicolenus dactylopterus blackbelly rosefish 179-754 Reed et al. 2006

Pontinus longispinus longspine scorpionfish 267-311 Matlock et al. 1990

Xiphiidae

Xiphias gladius swordfish Reed et al. 2006
604

Table 14-5.

Deepwater shrimps of the western Atlantic Ocean associated soft bottom communities below 200 m. From Jones et al. 

1994, originally described in Cervignon et al. 1993).

Family Name Maximum size Distribution Habitat Depth/Temperature Range

Inches cm

Solenoceridae

Royal Red Shrimp 8.9 22.5 Massachusetts to northern Sand, clay, mud and 70-915 m

Pleoticus (Hymenopenaeus) robustus South America including Gulf muddy clay bottoms (250-475 m)

(Smith, 1885) of Mexico and coasts of central 9 -12° C

America.

Salmon shrimp 4.3 11 North Carolina to Brazil including n/a 30-915 m

Mesopenaeus tropicalis Florida, Gulf of Mexico and (>200 m)

(Bouvier, 1905) Caribbean Sea

Penaeidae

Rose shrimp 4.9 12.5 Massachusetts to Venezuela Mud and sandy mud 3-752 m

Parapenaeus politus bottoms (65-275 m)

Smith, 1881

Megalops or pinkspeckled 5.9 15 Massachusetts to Brazil including Sandy and Muddy 120-750 m

shrimp the Bahamas, Gulf of Mexico, and bottoms

Penaeopsis serrata Caribbean Sea

Bate, 1881

Pandalidae

Armed nylon shrimp 4.9 12.4 North Carolina to Guianas including Muddy bottoms 40-880 m

Heterocarpus ensifer the Caribbean Sea

A. Milne Edwards, 1881

Lesser striped shrimp 3.3 8.4 South Carolina to Brazil Muddy bottoms 190-1350 m

Plesionika acanthonotus

(S. I. Smith, 1882)

Striped soldier shrimp 6.5 16.6 North Carolina to Surinam including Muddy bottoms 50-690 m

Plesionika edwardsii the Gulf of Mexico & Antilles

(Brandt, 1851)

Striped gladiator shrimp 4.7 12 Florida, Western Gulf of Mexico, Muddy bottoms 100-1250 m

Plesionika ensis Antilles, Guianas, & Brazil

(A. Milne Edwards, 1881)

Longtail shrimp >3.1 >8 Gulf of Mexico to northern South Soft bottoms 55-410 m

Plesionika longicauda America

(Rathbun, 1901)
605

Table 14-5. Continued

Family Name Maximum size Distribution Habitat Depth/Temperature Range

Inches cm

Aristeidae

Giant red shrimp 8.9 22.5 Massachusetts to northern South Muddy bottoms 170-1350 m

Aristaeomorpha foliacea America including the Gulf of Mexico

(Risso, 1827) & Caribbean Sea

Purplehead gamba prawn 7.6 19.3 North Carolina to Surinam including Soft bottoms 200-820 m

Aristeus antillensis the Gulf of Mexico & Caribbean Sea

(Milne Edwards and Bouvier, 1909)

Scarlet shrimp 13.1 33.4 Newfoundland to northern South Muddy bottoms 270-1850 m

Plesiopenaeus edwardsianus America including the Gulf of Mexico (400-900 m)

(Johnson, 1868) & Caribbean Sea
606

Table 14-6. 

Fish and invertebrate taxa taken commercially in the northern GOM (U.S. waters) in 

decreasing order of commercial dollar value. Deepwater Species designated in bold. 

All values are annual averages for the period 2000-2007. Source: Fisheries Statistics 

Division ST1 (FSD) of the NMFS (NMFS 2008). From LGL 2009.

Common Name Scientific Name Pounds Dollar Value (US) Percent Dollar

Value (US)

Shrimp, Brown Farfantepenaeus aztecus 127,426,610 203,525,795 28.4

Shrimp, White Litopenaeus setiferus 101,305,075 177,981,856 24.8

Oyster, Eastern Crassostrea virginica 23,681,186 58,168,167 8.1

Menhaden, Gulf Brevoortia patronus 1,081,127,556 54,144,592 7.6

Crab, Blue Callinectes sapidus 61,128,125 43,619,711 6.1

Shrimp, Pink Farfantepenaeus duorarum 13,237,192 27,809,743 3.9

Crab, Florida Stone Claws Menippe mercenaria 5,800,380 24,171,885 3.4

Lobster, Caribbean Spiny Panulirus argus 3,932,025 20,156,482 2.8

Grouper, Red Epinephelus morio 6,300,903 12,944,474 1.8

Snapper, Red Lutjanus campechanus 4,394,552 10,945,823 1.5

Tuna, Yellowfin Thunnus albacares 3,349,396 10,491,828 1.5

Shrimp, Dendrobranchiata Shrimp Suborder 2,762,392 8,407,760 1.2

Mullet, Striped (Liza) Mugil cephalus 12,401,802 8,358,186 1.2

Gag Mycteroperca microlepis 2,510,539 6,441,548 0.9

Snapper, Vermilion Rhomboplites aurorubens 1,957,037 3,902,361 0.5

Drum, Black Pogonias cromis 5,095,562 3,575,429 0.5

Snapper, Yellowtail Ocyurus chrysurus 1,258,740 2,717,862 0.4

Grouper, Yellowedge Epinephelus flavolimbatus 1,017,550 2,658,727 0.4

Shrimp, Rock Sicyonia brevirostris 1,681,983 2,249,763 0.3

Sharks 874,311 2,019,884 0.3

Shrimp, Seabob Xiphopenaeus kroyeri 4,653,430 1,970,282 0.3

Swordfish Xiphias gladius 814,694 1,822,322 0.3

Catfish, Blue Ictalurus furcatus 3,433,441 1,614,270 0.2

Mackerel, King and Cero Scomberomorus cavalla/regalis 1,317,458 1,466,095 0.2

Mackerel, King Scomberomorus cavalla 985,712 1,211,584 0.2

Amberjack, Greater Seriola dumerili 1,087,468 1,056,163 0.1

Grouper, Black Mycteroperca bonaci 417,192 1,054,001 0.1

Shrimp, Royal Red Pleoticus robustus 470,095 1,048,030 0.1

Pompano, Florida Trachinotus carolinus 308,544 995,822 0.1

Ladyfish Elops saurus 1,437,907 862,799 0.1

Scamp Mycteroperca phenax 325,697 846,620 0.1

Flatfish Pleuronectiformes 407,373 797,752 0.1

Finfishes, Unc General 2,098,136 794,144 0.1

Mackerel, Spanish Scomberomorus maculatus 1,335,034 731,828 0.1

Tilefish Malacanthidae 439,419 682,412 0.1

Sheepshead Archosargus probatocephalus 2,037,239 671,438 0.1

Catfish, Channel Ictalurus punctatus 1,315,173 662,955 0.1

Buffalofishes Ictiobus spp. 3,370,904 581,891 0.1

Shrimp, Marine, Other 214,729 581,576 0.1

Snapper, Gray Lutjanus griseus 312,223 578,521 0.1

Finfishes, Unc Bait/Animal Food 1,700,423 570,156 0.1

Grouper, Snowy Epinephelus niveatus 243,299 547,017 0.1

Ballyhoo Hemiramphus brasiliensis 657,657 504,102 0.1

Scads Carangidae 721,776 484,118 0.1

Dolphinfish Coryphaena hippurus 349,132 455,029 0.1

Croaker, Atlantic Micropogonias undulatus 86,695 451,349 0.1

Snapper, Mutton Lutjanus analis 215,000 403,587 0.1

Sardine Spanish Sardinella aurita 1,589,857 378,855 0.1

Butterfish, Gulf Peprilus burti 802,857 361,029 0.1

Tuna, Bluefin Thunnus thynnus 76,600 345,746 0.0

Shrimp, Atlantic & Gulf, Roughneck Trachypenaeus similis 568,143 331,652 0.0

Grouper, Warsaw Epinephelus nigritus 164,097 316,489 0.0

Shark, Blacktip Carcharhinus limbatus 1,201,625 313,022 0.0

Grunts Haemulidae 435,912 309,195 0.0

Herring, Atlantic Thread Opisthonema oglinum 1,950,158 277,850 0.0

Crab, Deepsea Golden Chaceon fenneri 233,354 258,468 0.0

Shad, Gizzard Dorosoma cepedianum 1,149,656 252,390 0.0

Cobia Rachycentron canadum 115,774 241,807 0.0
607

Table 14-6. Continued

Common Name Scientific Name Pounds DollarValue (US) Percent Dollar

Value (US)

Mullets Mugil spp. 300,736 235,563 0.0

Shark, Sandbar Carcharhinus plumbeus 822,699 235,166 0.0

Jack, Crevalle Caranx hippos 387,572 233,819 0.0

Scups or Porgies Sparidae 243,998 231,214 0.0

Pinfish Lagodon rhomboides 44,340 215,985 0.0

Finfishes, Unc For Food 674,433 197,774 0.0

Mojarras Gerreidae 249,333 187,975 0.0

Snapper, Silk Lutjanus vivanus 80,838 177,109 0.0

Hind, Speckled Epinephelus drummondhayi 79,726 165,502 0.0

Seatrout, Spotted Cynoscion nebulosus 82,966 160,853 0.0

Wahoo Acanthocybium solandri 135,889 158,912 0.0

Herrings Clupeidae 1,007,150 156,300 0.0

Tuna, Little Tunny Euthynnus alletteratus 392,580 144,981 0.0

Tuna, Bigeye Thunnus obesus 38,511 132,672 0.0

Leatherjackets Carnagidae 103,665 127,437 0.0

Catfish, Flathead Pylodictis olivaris 255,478 121,971 0.0

Mackerel, Chub Scomber colias 204,110 121,699 0.0

Runner, Blue Caranx crysos 253,723 120,967 0.0

Bowfin Amia calva 137,670 113,640 0.0

Bonito, Atlantic Sarda sarda 80,325 112,630 0.0

Tilefish, Blueline (DW) Caulolatilus microps 122,561 109,760 0.0

Sea Bass, Black Centropristis striata 161,843 109,325 0.0

Porgy, Red Pagrus pagrus 96,938 103,239 0.0

Flounder, Southern Paralichthys lethostigma 83,869 99,322 0.0

Snapper, Lane Lutjanus synagris 52,884 90,369 0.0

Escolar Lepidocybium flavobrunneum 121,980 87,031 0.0

Groupers Serranidae 38,315 84,480 0.0

Mullet, white Mugil curema 149,670 83,001 0.0

Drum, Freshwater Apoldinotus grunniens 541,676 82,136 0.0

Pigfish Orthopristis chrysoptera 28,247 80,737 0.0

Hogfish Lachnolaimus maximus 36,141 79,411 0.0

Amberjack, Lesser Seriola fasciata 66,655 73,224 0.0

King Whiting Menticirrhus americanus 126,338 73,057 0.0

Triggerfish, Gray Balistes capriscus 68,194 70,827 0.0

Seatrout, Sand Cynoscion arenarius 105,370 67,330 0.0

Shark, Atlantic Sharpnose Rhizoprionodon terraenovae 140,138 55,309 0.0

Tilefish, Goldface Caulolatilus chrysops 36,846 52,706 0.0

Jack, Almaco Seriola rivoliana 52,718 48,527 0.0

Lobster, Slipper Sycllarides squammosus 10,512 46,370 0.0

Snapper, Queen Etelis oculatus 19,694 41,868 0.0

Shark, Finetooth Carcharhinus isodon 77,303 41,690 0.0

Scad, Bigeye Selar crumenophthalmus 247,372 40,873 0.0

Bluefish Pomatomus saltatrix 126,246 39,503 0.0

Oilfish Ruvettus pretiosus 44,373 36,005 0.0

Jacks Carangidae 59,810 34,820 0.0

Drum, Red Sciaenops ocellatus 24,317 34,414 0.0

Cutlassfish, Atlantic Trichiurus lepturus 35,776 33,237 0.0

Suckers Catostomidae 81,078 31,501 0.0

Jack, Bar Caranx ruber 38,080 31,259 0.0

Barrelfish Hyperoglyphe perciformis 14,912 29,069 0.0

Snapper, Black Apsilus dentatus 14,888 25,052 0.0

Permit Trachinotus falcatus 17,361 24,949 0.0

Snappers Lutjanidae 13,304 24,053 0.0

Anchovies Engraulidae 106,489 23,212 0.0

Shark, Great Hammerhead Sphyrna mokarran 89,196 21,795 0.0

Wenchman Pristipomoides aquilonaris 16,674 21,318 0.0

Tuna, Blackfin Thunnus atlanticus 31,901 21,077 0.0

Shark, Shortfin Mako Isurus oxyrinchus 23,747 20,444 0.0

Shark, Bull Carcharhinus leucas 70,871 19,604 0.0

Brotula, Bearded Brotula barbata 16,608 18,401 0.0

Spadefish, Atlantic Chaetodipterus faber 36,118 15,995 0.0

Black Driftfish Hyperoglyphe bythites 11,137 15,591 0.0

Margate Haemulon album 22,334 13,481 0.0
608

Table 14-6. Continued

Common Name Scientific Name Pounds Dollar Value (US) Percent Dollar

Value (US)

Grouper, Yellowfin Mycteroperca venenosa 5,948 13,415 0.0

Scorpionfishes Scorpaeniformes 11,904 13,033 0.0

Porgy, Knobbed Calamus nodosus 19,803 13,020 0.0

Spot Leiostomus xanthurus 32,853 12,550 0.0

Shark, Lemon Negaprion brevirostris 44,990 12,211 0.0

Tilefishes (DW) Malacanthidae 26,584 12,128 0.0

Rudderfish, Banded Seriola zonata 12,880 11,028 0.0

Snapper, Blackfin (DW) Lutjanus buccanella 4,987 10,551 0.0

Shark, Spinner Carcharhinus brevipinna 30,884 10,359 0.0

Tuna, Albacore Thunnus alalunga 15,321 10,022 0.0

Mackerel, (Scomber) Scombridae 15,479 9,363 0.0

Barracudas Sphyraena spp. 14,835 9,324 0.0

Hind, Red Epinephelus guttatus 5,447 9,202 0.0

Amberjack Seriola spp. 8,738 7,778 0.0

Shark, Blacknose Carcharhinus acronotus 21,928 7,656 0.0

Grouper, Marbled Dermatolepis inermis 3,009 5,953 0.0

Grouper, Misty Epinephelus mystacinus 2,557 5,557 0.0

Hake, Atlantic, Red/White Urophycis chuss/tenuis 5,178 5,313 0.0

Tunas Scombridae 2,298 5,212 0.0

Porgy, Whitebone Calamus leucosteus 4,815 4,953 0.0

Flyingfishes Exocoetidae 33,991 4,829 0.0

Porgy, Jolthead Calamus bajonado 5,251 4,340 0.0

Tripletail, Atlantic Lobotes surinamensis 3,755 3,448 0.0

Sea Catfishes Ariidae 12,567 3,411 0.0

Puffers Tetradontidae 4,997 3,394 0.0

Rays Rajiformes/Myliobatiformes 19,400 3,383 0.0

Shark, Longfin Mako Isurus paucus 4,037 3,083 0.0

Drums Sciaenidae 4,864 2,267 0.0

Snapper, Dog Lutjanus jocu 1,699 1,889 0.0

Rosefish, Blackbelly (DW) Helicolenus dactylopterus 1,590 1,789 0.0

Scorpionfish, Spotted Scorpaena plumieri 1,208 1,780 0.0

Snapper, Cubera Lutjanus cyanopterus 1,476 1,603 0.0

Creolefish, Atlantic Paranthias furcifer 2,193 1,546 0.0

Ray, Stingrays Rajiformes/Myliobatiformes 4,953 1,360 0.0

Shark, Silky Carcharhinus falciformis 4,152 1,357 0.0

Parrotfishes Scaridae 1,207 1,192 0.0

Shark, Tiger Galeocerdo cuvier 3,708 1,157 0.0

Bigeye Priacanthus arenatus 1,964 1,149 0.0

Sand Perch Diplectrum formosum 612 1,141 0.0

Grouper, Yellowmouth Mycteroperca interstitialis 489 1,061 0.0

Pompano, African Alectis ciliaris 795 971 0.0

Scorpionfish, Spinycheek Neomerinthe hemingwayi 838 898 0.0

Eel, Conger Congridae 1,004 876 0.0

Hind, Rock Epinephelus adscensionis 425 791 0.0

Snapper, Caribbean Red Lutjanus purpureus 816 749 0.0

Bass, Longtail ( Hemanthias leptus 680 667 0.0

Triggerfish, Queen Balistes vetula 582 599 0.0

Tuna, Skipjack Katsuwonus pelamis 572 469 0.0

Lookdown Selene vomer 680 467 0.0

Opah Lampris guttatus 346 445 0.0

Squirrelfishes Holocentridae 607 357 0.0

Runner, Rainbow Elagatis bipinnulata 560 315 0.0

Eels, Snake Ophichthidae 231 312 0.0

Sea Chubs Kyphosidae 538 283 0.0

Tilefish, Sand Malacanthus plumieri 166 244 0.0

Shark, Thresher Alopias vulpinus 531 214 0.0

Jack, Horse-eye Caranx latus 248 172 0.0

Graysby Cephalopholis cruentata 64 117 0.0

Snapper, Schoolmaster Lutjanus apodus 82 111 0.0

Shark, Bonnethead Sphyrna tiburo 338 96 0.0

Pomfrets Bramidae 82 78 0.0

Jack, Black Caranx lugubris 139 76 0.0
609

Table 14-7.

Species listed in the Essential Fish Habitat Amendment to Gulf of Mexico Fishery 

Management Plans. Deepwater species in bold. Source: GMFMC (2005b). Used with 

permission from LGL 2009.

FMP Common name Scientific Name

Red Drum (1) Drum, Red Sciaenops ocellatus

Reef Fish (43) Balistidae - Triggerfishes (1)

Triggerfish, Gray Balistes capriscus

Carangidae - Jacks (4)

Amberjack, Greater Seriola dumerili

Amberjack, Lesser Seriola fasciata

Jack, Almaco Seriola rivoliana

Rudderfish, Banded Seriola zonata

Labridae - Wrasses (1)

Hogfish Lachnolaimus maximus

Lutjanidae - Snappers (14)

Snapper, Queen Etelis oculatus

Snapper, Mutton Lutjanus analis

Snapper, Schoolmaster Lutjanus apodus

Snapper, Blackfin Lutjanus buccanella

Snapper, Red Lutjanus campechanus

Snapper, Cubera Lutjanus cyanopterus

Snapper, Gray Lutjanus griseus

Snapper, Dog Lutjanus jocu

Snapper, Mahogany Lutjanus purpureus

Snapper, Lane Lutjanus synagris

Snapper, Silk Lutjanus vivanus

Snapper, Yellowtail Ocyurus chrysurus

Wenchman Pristipomoides aquilonaris

Snapper, Vermilion Rhomboplites aurorubens

Malacanthidae - Tilefishes (5)

Tilefish, Goldface Caulolatilus chrysops

Tilefish, Blackline Caulolatilus cyanops

Tilefish, Anchor Caulolatilus intermedius

Tilefish, Blueline Caulolatilus microps

Tilefish, Golden Lopholatilus chamaeleonticeps

Serrinidae - Groupers (18)

Sand Perch, Dwarf Diplectrum bivittatum

Sand Perch Diplectrum formosum

Hind, Rock Epinephelus adscensionis

Hind, Speckled Epinephelus drummondhayi

Grouper, Yellowedge Epinephelus flavolimbatus

Hind, Red Epinephelus guttatus

Grouper, Goliath Epinephelus itajara

Grouper, Red Epinephelus morio

Grouper, Misty Epinephelus mystacinus
610

Table 14-7. Continued.

FMP Common name Scientific Name

Grouper, Warsaw Epinephelus nigritus

Grouper, Snowy Epinephelus niveatus

Grouper, Nassau Epinephelus striatus

Grouper, Marbled Dermatolepis inermis

Grouper, Black Mycteroperca bonaci

Grouper, Yellowmouth Mycteroperca interstitialis

Gag Mycteroperca microlepis

Scamp Mycteroperca phenax

Grouper, Yellowfin Mycteroperca venenosa

Coastal Migratory Mackerel, King Scomberomorus cavalla

Pelagic (3) Mackerel, Spanish Scomberomorus maculatus

Cobia Rachycentron canadum

Shrimp (4) Shrimp, Brown Farfantepenaeus aztecus

Shrimp, White Farfantepenaeus setiferus

Shrimp, Pink Farfantepenaeus duorarum

Shrimp, Royal Red Pleoticus robustus

Stone Crab (2) Crab, Florida Stone Claws Menippe mercenaria

Crab, Florida Stone Claws Menippe adina

(Ceder Key N)

Spiny Lobster (2) Lobster, Caribbean Spiny Panulirus argus

Lobster, Slipper Sycllarides squammosus

611

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