Technical Summaries from

Selected Environmental Studies

of the Northeastern Gulf of Mexico

U.S. DeDartment of the Interior

Minerals Management Service Gulf of Mexico OCS Region

OCS Report

MMS 96-0025
Technical Summaries from

Selected Environmental Studies

of the Northeastern Gulf of Mexico

Compiled by

Minerals Management Service

Gulf of Mexico OCS Region

Published by

U.S. Department of the Interior Minerals Management Service Gulf of Mexico OCS Region

OCS Report

MMS 96-0025

New Orleans

July 1996
Availability

The technical summaries contained in this OCS report were prepared by various

contractors (refer to individual studies) under contract to the Minerals Management Service (MMS). The summaries were compiled and prepared for publication by the MMS, Gulf of Mexico OCS Region, Environmental Studies Section, located in New

Orleans, Louisiana.

Copies of the publication can be obtained from the MMS Public Information Office

at the address below. Questions about individual studies should be addressed to

the Environmental Studies Section (MS 5430), 1 201 Elmwood Park Boulevard,

New Orleans, Louisiana 70123-2394.

Minerals Management Service

Gulf of Mexico OCS Region

Public Information Office (MS 5034)

1201 Elmwood Park Boulevard

New Orleans, Louisiana 70123-2394

(504) 736-2519

(800) 200-GULF

FAX (504) 736-2620

AvaiabiIity lii
Preface

The Outer Continental Shelf (OCS) Environmental Studies Program, administered by the

Minerals Management Service (MMS) of the U.S. Department of the Interior, has sponsored

hundreds of environmental and socioeconomic studies in the Atlantic and Pacific Oceans,

Alaskan waters, and the Gulf of Mexico OCS Region since the program's inception in 1 973.

More than $550 million has been spent in gathering the data that support OCS decisions.

Most of the reports are available through the MMS Public Information Office, the National

Technical Information Service, and regional libraries. The Gulf of Mexico OCS Region of the

MMS initiated a project to summarize this vast collection of data and made the condensed

information more readily available to potential users. The resulting technical summaries are

anticipated to serve the purposes of many users of the information generated by the OCS

Environmental Studies Program.

This publication represents a collection of MMS technical summaries of 39 Northeastern

Gulf of Mexico final reports. These technical summaries represent selected studies in the

northeastern Gulf of Mexico only.

The summaries are prepared following a standard format designed to provide the reader

with a synopsis of administrative and technical information. A map is included, when

available, to show the area of study. In this publication, the summaries are organized by

studies series representing aspects of the OCS Environmental Studies Program. Topics

include Environmental Mapping, Physical Oceanography, Marine Ecosystems, Coastal

Studies, Living Marine Resources, Ecological Effects, Socioeconomics, Cultural Resources,

and Information Management.

Summarizing information contained in hundreds of lengthy "grey literature" reports is a

major undertaking. Many individuals contributed to this effort. Under contract to the MMS,

Continental Shelf Associates, Inc. (CSA) furnished a team of scientifically qualified technical

writers and editors to produce the tightly written summaries contained in this publication.

Their attention to detail has resulted in summaries that accurately characterize the scientific

findings of the complex, and often lengthy, original reports. Technical summaries of the

more recent studies have been prepared by the original contractor.

Preface V
Table of Contents

Preface v

Introduction ix

Section I: Environmental Mapping 1

Baseline Monitoring Studies, Mississippi, Alabama, Florida, Outer

Continental Shelf 1975-1976 3

Eastern Gulf of Mexico Marine Habitat Study 7

Florida Big Bend Seagrass Habitat Study 11

Assessment of Hurricane Damage in the Florida Big Bend Seagrass

Beds 15

Mapping of Submerged Vegetation Using Remote Sensing

Technology 19

Section II: Physical Oceanography 23

Southwest Florida Shelf Circulation Model 25

Gulf of Mexico Satellite Radar Altimetry 29

Gulf of Mexico Physical Oceanography Program Final Report,

Year 4. Vol. 1, Executive Summary; Vol. II, Technical Report . . 33

Gulf of Mexico Circulation Modeling Study Annual Progress

Report, Year 1 37

Gulf of Mexico Modeling Study Annual Progress Report.

Year 2 41

Compilation and Summation of Historical and Existing Physical

Oceanographic Data from the Eastern Gulf of Mexico 45

Table of Contents vii
Section III: Marine Ecosystems 49

The Ecological Communities of the Continental Slope and

Adjacent Regimes of the Northern Gulf of Mexico 51

Northern Gulf of Mexico Topographic Features Study.

Vols. I through VI 55

Annual Report for Northern Gulf of Mexico Continental Slope

Study 59

Tuscaloosa Trend Regional Data Search and Synthesis Study

Vol. I, Synthesis Report; Vol. II, Supplemental Report 63

Southwest Florida Shelf Benthic Communities Study, Year 5

Annual Report. Vol. I, Executive Summary; Vol. II, Technical

Discussion; Vol. III, Appendices. 67

Gulf of Mexico Continental Slope Study Annual Report, Year 2 . . . 71

Final Report on the Baseline Environmental Survey of the MAFLA

Lease Areas 75

Final Report on the Quality Control of Trace Metal Analysis for

the MAFLA Baseline Environmental Survey 79

Multivariate Analysis of the MAFLA Water Column Baseline Data 83

lchthyoplankton Abundance and Diversity in the Eastern

Gulf of Mexico 87

Section IV: Coastal Studies 91

Rare, Threatened, and Endangered Vertebrates of Southwest

Florida and Potential OCS Activity Impacts 93

Rare, Threatened, and Endangered Vertebrates of Southwest

Florida and Potential OCS Activity Impacts 95

Alabama Coastal Region Ecological Characterization. Vol. 1,

Coastal Bibliography; Vol. 2, A Synthesis of Environmental Data 97

Alabama Coastal Region Ecological Characterization. Vol. 3,

viii Tab'e of Contents
A Socioeconomic Study 101

Florida Coastal Ecological Characterization: A Socioeconomic

Study of the Northwestern Region 107

The Ecology of Irregularly Flooded Salt Marshes of the

Northeastern Gulf of Mexico: A Community Profile 111

Northwestern Florida Ecological Characterization: An Ecological

Atlas 115

Ecological Characterization Atlas of Coastal Alabama: Map

Narrative 11 9

Section V: Living Marine Resources 123

A Review of the Ecology, Behavior, and Life History of the

Bottlenose Dolphin 125

Proceedings of a Workshop on Cetaceans and Sea Turtles in the

Gulf of Mexico: Study Planning for Effects of Outer Continental

Shelf Development 1 29

Marine Birds of the Southeastern United States and Gulf of

Mexico Part I, Gaviiformes through Pelecaniformes; Part II,

Anseriformes; Part Ill, Charadriiformes 133

Section VI: Ecological Effects 135

Habitat Impacts of Offshore Drilling: Eastern Gulf of Mexico 137

Dispersed Oil Toxicity Tests with Species Indigenous to the

Gulf of Mexico 139

Quality Control for MAFLA IV and South Texas II Investigations 143

A Numerical Modeling and Observational Effort to Develop

the Capability to Predict the Currents in the Gulf of Mexico for

Use in Pollutant Trajectory Computation: A Guide to a General

Circulation Model of the Gulf of Mexico 149

Section VII: Socioeconomics 153

Table of Contents ix
Indicators of the Direct Economic Impacts Due to Oil and Gas

Development in the Gulf of Mexico. Results of Year I.

Executive Summary; Vol. I, Narrative; Vol. II, Exhibits 155

Section VIII: Cultural Resources 1 61

Cultural Resources Evaluation of the Northern Gulf of Mexico

Continental Shelf. Vols. I through III 1 63

Section IX: Information Management 167

Bibliography of Benthic Studies in the Coastal and Estuarine

Areas of Florida 169

The Mississippi, Alabama, Florida, Outer Continental Shelf

Baseline Environmental Survey MAFLA 1977/1 978 173

Taxonomic Guide to the Polychaetes of the Northern Gulf of

Mexico 177

Mississippi-Alabama Shelf Pinnacle Trend Habitat Mapping

Study. Final Report 181

x Table of Contents
SELECTED ENVIRONMENTAL

STUDIES OF THE

NORTHEASTERN

GULF OF MEXICO

Introduction

As the Nations designated steward of the mineral resources on the Outer

Continental Shelf (OCS), the Department of the Interior's Minerals Management

Service (MMS) is committed to achieving the proper balance between providing

energy for the American people and protecting unique and sensitive coastal and

marine environments. MMS's primary responsibilities are prudent leasing and safe

management of Federal lands for exploration and development of natural gas and

oil on the OCS; and the collection and distribution of bonuses, rentals, and

royalties from companies that lease and produce minerals from onshore and

offshore Federal and Indian lands.

MMS responds to these challenges through a commitment to quality science,

judicious leasing, and safe, clean operations. MMS works diligently to protect the

environment and to achieve excellence in every aspect of our Congressionally

mandated mission.

Quality Science

Quality science is fundamental to MMS's approach to identifying and assessing

areas for potential resource development, determining potential environmental

risks, and ensuring safe, clean offshore operations.

MMS conducts, funds, and publishes the results of hundreds of scientific and

technical projects and studies that enable us to balance environmental concerns

with leasing decisions. These scientific findings may result in revised regulations,

stipulations in lease agreements, or special orders to offshore operators.

After analyzing the results of these findings, MMS often determines that good

leasing decisions require additional wide-ranging oceanographic, environmental,

marine life, socioeconomic, or ecological studies. MMS scientists and engineers
determine ways of protecting environmentally sensitive areas or species, or

mitigating potential harm from offshore activities.

MMS conducts rigorous engineering, geological, geophysical, and other scientific

assessments on which we base decisions for approval of or modification to

lessees' plans for OCS activity. These assessments also enable MMS to measure

the long-term environmental and ecological effects of offshore natural gas and oil

production.

Upholding Judicious Leasing

MMS provides the Nation with a schedule of lease sales that will produce critically

needed domestic energy resources. We base leasing decisions on a 5-year

Program of schedules, which shows dates and locations of proposed lease sales.

In addition, the 5-year Program gives information relating to geographical,

geological, and environmental studies.

MMS balances environmental considerations, the potential for discovery of natural

gas and oil, and the potential impact on coastal communities. Interested parties,

including State and local governments and the general public, have several

opportunities to participate in the decisionmaking process and to review and

submit comments to MMS on the program.

The Comprehensive 5-Year Program is adopted only after MMS has reviewed the

comments and balanced them with national interest considerations, and has

obtained approval from the Secretary of the Interior after a review by the President

and the Congress. Developing an approved, final 5-Year Program is a process that

takes two to three years.

Ensuring Safe and Clean Operations

From the day a bidder is awarded a lease to operate on the OCS until drilling and

production cease--often up to 30 years later--MMS devotes constant attention to

safety through a combination of required plans, permits, training, inspections, and,

if necessary, penalties for noncompliance with the regulations.

Numerous Federal laws--some under the jurisdiction of MMS, others under the

jurisdiction of agencies such as the Environmental Protection Agency or the

U.S. Coast Guard--govern offshore activities. These are interpreted and explained

in regulations that specify the procedures operators must follow to ensure safe

offshore operations. Among the many issues addressed in these regulations are

xii ntrod u cti on
requirements for inspections, safety training and drills, and accident prevention

procedures.

Before and during OCS operations, operators and lessees must prepare and secure

approval of detailed plans for exploration and development; they must also secure

permits for drilling and for construction or modifications to platform structures and

pipelines. These plans and procedures must meet MMS's stringent regulations and

operating procedures, which are based on the best available and safest

technologies.

A crucial tool in maintaining safe operations is the inspection of offshore facilities.

Federal law and regulations require a complete inspection of every offshore

platform. Petroleum engineering technicians conduct these inspections and

evaluate the overall condition of a facility and its operations.

In the rare event that an accident does occur, MMS strives to minimize harm to

individuals and damage to the environment. MMS may revise regulations and

operating orders for a particular facility based on results from program

investigations and accident reports. Revisions to regulations may be done in an

effort to prevent future accidents.

MMS enforces its network of safety regulations and procedures through warnings

and penalties. Penalties may include a component or facility shut-in, or civil

penalties of up to $20,000 per day for failure to correct an offshore operations

violation. Penalties may be as high as $500,000 per day or 10 years in prison or

both, for knowing and willful violation of OCS rules, regulations, leases, or

permits.

Protecting the Environment

MMS conducts a multifaceted Environmental Studies Program, which generates

the scientific research essential to making sound leasing and operating decisions

before exploration and development can begin on any particular OCS tract.

In addition, MMS conducts a special program designed to identify and protect

valuable underwater prehistoric and historic sites on the OCS. MMS's extensive,

constantly evolving Environmental Studies Program supplies the scientific and

technical information needed to determine which offshore areas are acceptable for

leasing, as well as to predict, assess, and manage the impact of OCS natural gas

and oil activities on the human, marine, and coastal environments.

The Studies Program provides information for the environmentally safe operation

of natural gas and oil activities and for developing the 5-Year Program. MMS

Introduction
publishes draft and final environmental impact statements for all proposed leasing

areas, describing the existing environment, analyses of possible effects of offshore

activities on the environment, oil-spill risk analyses and proposed mitigating

measures, as well as thorough environmental assessments, which are conducted

after leases are awarded but before OCS operations may begin.

MMS protects underwater archaeological sites by using remote-sensing

instruments that detect shipwrecks of whaling, fishing, and military vessels,

allowing MMS to determine specific measures that are necessary to protect them.

Managing Royalties

Natural gas, oil, geothermal energy, coal, and other minerals constitute some of

our Nation's most important natural resources. These resources belong to all

Americans, and Congress has entrusted MMS with ensuring that the Nation

receives a fair and appropriate return from interests that lease or develop them.

The Royalty Management Program (RMP) of the MMS collects and distributes the

bonuses, rents, and royalties from companies that lease and produce minerals

from onshore and offshore Federal and Indian lands. These revenues are one of

the largest non-tax sources of income to the U.S. Treasury, ranging from about

$3.4 billion to $10 billion annually, depending on the volume of production, prices,

and amounts of offshore leasing. Sources of these revenues include 26,000

Federal and Indian producing offshore and onshore leases in rental status.

The RMP collects these funds from the mineral industry and distributes them to

State governments, Indian tribes, individual Indian mineral owners, and the public

at large through several U.S. Treasury funds.

Federal law requires that these funds be distributed to several types of recipients.

The Federal Government, which receives the largest share, disburses the revenues

among the General Fund of the U.S. Treasury; special Federal funds for acquisition

of National and State Parks, conservation, and recreation areas; the Historic

Preservation Fund; and coastal states, Indian tribes, and some 29,000 individual

Indian recipients.

These funds are used to acquire and maintain recreational and conservation lands;

they are used for State-sponsored education, roads, and other projects; for

development of the National Park System; and for acquisition and management of

historic properties.

To carry out the complex tasks of collecting, accounting for, and disbursing

revenues from thousands of companies to thousands of recipients, the RMP has

xiv Introduction
developed and implemented automated systems that provide accounting data and

tract production information, and account for bonuses and rentals from onshore

Federal leases that are not yet producing.

The People of MMS

The MMS workforce consists of about 1 ,800 individuals in more than 100

occupations. About half of these individuals occupy positions officially classified

as professional. About 50 percent of this group have specialized positions as

biologists, oceanographers, petroleum engineers, geologists, geophysicists,

paleontologists, economists, and automated data processing specialists, among

others. Another 30 percent are accountants and auditors, some of who are

certified public accountants. More than 20 percent of MMS biologists and

physical scientists hold doctoral degrees, while more than one-quarter of all

professional personnel have their Master's degrees.

Environmental Studies Program

MMS supports and administers a multidisciplinary Environmental Studies Program

(ESP) to develop information needed for assessment and management of impacts

to marine and coastal environments that may be affected by OCS oil and gas

activities. Since its beginning, the ESP has sponsored over $139 million through

more than 220 environmental studies in the Gulf of Mexico, and over $550 million

throughout the agency. These funds have supported studies in all aspects needed

for a thorough understanding of the complex nature of the Gulf of Mexico and aid

in the wise protection of the valuable resources of the Gulf of Mexico.

The gas and oil activities on the Gulf of Mexico OCS are a large contributor to our

National energy needs. As the most mature area where OCS gas and oil

production occurs, it is the primary focus of MMS's research, regulation, and

monitoring effort with regard to the production of offshore gas and oil.

The Environmental Studies Program provides the MMS with the environmental,

social, and economic information necessary for the bureau to carry out its

mandate as specified in the Outer Continental Shelf Lands Act, as amended in

1978. The studies are specifically designed to provide information for

management decisions both before and after lease sales. Study development is a

continuing process and recognizes the need for modification, addition, or deletion

of identified studies as information is developed by other efforts, as new

environmental or management concerns are recognized, and as modifications in

the OCS leasing process are implemented.

Introduction xv
Each study produces information that is published by MMS and made available to

the public through the MMS Gulf of Mexico OCS Region's Public Information

Office. The MMS uses information from the ESP to judge the potential

environmental problems associated with all levels of gas and oil activities. Final

reports, maps, digital data, and photographic or video products resulting from

these contracted environmental, social, or economic studies are available to the

public from the MMS and from the National Technical Information Service (NTIS),

and occasionally from other sources.

Technical Summaries

This document is a compilation of Technical Summaries for studies performed in

the Northeastern Gulf of Mexico. Technical Summaries provide a brief synopsis of

each study and are grouped by studies series and then listed by contract number.

Most of the studies contained in this document were funded during the 1 970's

and 1980's and on rare occasion into the early 1 990's. Listed studies that begin

with an alpha character were done during the 1970's when the program was

under the Bureau of Land Management.

For More Information

MMS receives a limited number of copies of each report from the study contractor

and makes those original copies available to a fixed distribution list including

Federal and State agencies, regional libraries, etc. Extra copies are available to the

general public. Some publications authored or published by the Gulf of Mexico

OCS Region are sold at a minimal price to recover printing costs. Persons wanting

copies of reports available from MMS should contact the Public Information Office

at the address provided. Persons wanting to inspect a copy of a specific report or

borrow a copy for short-term use or photocopying should also contact the Public

Information Office.

Minerals Management Service

Gulf of Mexico OCS Region

Public Information Office (MS 5034)

1201 Elmwood Park Boulevard

New Orleans, LA 701 23-2394

(504) 736-2519 or 1-800-200-GULF

FAX: (504) 736-2620

XVI Introduction
Persons desiring additional information regarding the MMS Environmental Studies

Program should contact

Minerals Management Service

Gulf of Mexico OCS Region

Office of Leasing and Environment

Chief, Environmental Studies Section (MS 5430)

1201 Elmwood Park Boulevard

New Orleans, LA 70123-2394

(504) 736-2789, FAX: (504) 736-2901

For information concerning the activities of the Gulf of Mexico OCS Region or the

MMS OCS Oil and Gas Program in general, please contact the Public Affairs

Officer (MS 5002) at the same address or by telephone at (504) 736-2595. Other

sources for study reports, such as original contractors or cooperating Federal

agencies, are listed under each report available from such a source.

The Minerals Management Service has made digital versions of many of the

documents cited in this report available through the Internet and the MMS WorldWide Web Home Page. The Technical Summaries and the full text of many

(without figures and tables) of the final reports are maintained by MMS in the

Environmental Studies Program Information System (ESPIS). This searchable

database is located at http://www.mms.gov/espis/.

Introduction xvii
ENVIRONMENTAL MAPPING

This study series seeks to produce and synthesize environmental information into

maps, preferably in an atlas format, for use by specialists and managers faced by

localized or regional proposals. By using the maps, space or proximity conflicts may be

identified, alternatives may be weighed, and the state of knowledge may be assessed.

When the database for a given area is large, many topics may be displayed;

alternatively, reduced information availability may restrict mapping at the present, but

the initial products may stimulate or guide work by other agencies to help fill these

gaps.

Environmental Mapping 1
REPORT TITLE: Baseline Monitoring Studies, Mississippi, Alabama, Florida, Outer

Continental Shelf 1975-1976.

MMS PUBLICATION NUMBER: Contract No. 08550-CT5-30.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico.

BACKGROUND: In 1974, the U.S. Department of the Interior funded a study to obtain

multidisciplinary, short-term, benchmark data on the Mississippi-Alabama-Florida (MAFLA)

Outer Continental Shelf (OCS) prior to oil and gas exploration in that region. The project

was extended to a long-term, three-year major study in 1975. The results of the

1975-1976 MAFLA investigations are contained in this report.

OBJECTIVES: (1) To conduct seasonal biological, geological, and physical surveys of the

water column and seafloor within the MAFLA region; (2) to determine range in

concentrations of high molecular weight hydrocarbons and trace metals in sediments, water

column, and selected benthic macrofauna; and (3) to conduct histopathological evaluations

on selected benthic macrofauna.

DESCRIPTION: The MAFLA/OCS study area was bounded by 81 °30' to 89° W long and

25°30' to 30°15 N lat. Depths ranged from 10 to 200 m. Sampling included water

column and benthic collections. A box corer (21 .3 x 30.5 x 43.2 cm) was used to obtain

sediment samples. Forty-five stations were occupied along six transects for box coring. A

9.1-m semi-balloon trawl with 9.5 mm mesh cod-end liner was used to take one sample per

station. Two dredge samples were taken at each station using a standard Capetown

dredge. Selected biota from trawl and dredge samples were removed for trace metal,

hydrocarbon, and histopathological analyses. The Florida Middle Ground area was sampled

(photography, observation, and collection) by divers at eight stations during summer and

winter.

Temperature and salinity were recorded using salinity-temperature-depth sensors,

expendable bathythermographs, water samplers, and reversing thermometers. A

transmissometer was used to determine the distribution of light transmission in the water

column. Thirty-liter Niskin bottles were used to collect water samples from surface and near

bottom. Duplicate zooplankton samples were collected during each of three sampling

seasons using 0.5-rn Nitex plankton nets with 0.202-mm mesh. Neuston samples were

collected using a 1-m floating plankton sampler with 0.202-mm mesh. In the laboratory,

sediment samples were analyzed for grain size, percent carbonate, total organic content,

benthic clay mineralogy, foraminifera, meiofauna, macrofauna, trace metals, adenosine

triphosphate, and hydrocarbons. Macrofauna, macroflora, and demersal fishes were

analyzed for hydrocarbons and trace metals. Water samples were analyzed for suspended

sediment mineralogy, particulates, primary productivity, chlorphyll , trace metals,

particulate organic carbon, dissolved organic carbon, dissolved hydrocarbons, and salinity

following standard methods.

Two ancillary projects were a'so undertaken. First was the compilation of a lithological map

using available geophysical information from the MAFLA area. Second was a pre-, during-,

Environmental Mapping 3
and post-operational monitoring of selected biological, chemical, and geological aspects of

the environment surrounding an exploratory drillsite.

SIGNIFICANT CONCLUSIONS: No petrogenic hydrocarbons were found in sediments,

water column, benthic organisms, or zooplankton. Abundance and diversity of organisms

suggested that the area was essentially a pristine environment. There was no evidence of

stress owing to influx of pollutants. Histopathological tests were also negative. Trace

metal concentrations in the samples were normal. The Mississippi-Alabama Shelf did show

evidence of hydrocarbon contamination due to input from the Mississippi River. Major

oceanographic influences were the Mississippi River, Loop Current, and Hurricane "Eloise."

STUDY RESULTS: Sedimentary zones were identified for the MAFLA area using particle

size ratios, percent carbonate, and mineralogy. The major influence on sediments of the

Mississippi-Alabama Shelf was input from the Mississippi River. Fine sediments, mostly

quartz sand and smectite, predominated in this deltaic region. Eastern and western flanks

of De Soto Canyon were comprised of lime muds and carbonate sands, respectively. East

of Cape San Bias, a transition to carbonate and kaolinite was evident. The West Florida

Shelf was covered by a carbonate sediment sheet; an inshore band of quartz sediment was

detected near the coastline.

Infaunal species variability was more closely correlated with depth than grain size. Epifaunal

taxa also displayed depth related patterns of abundance and diversity. Four epifaunal

assemblages were determined: Middle Shelf, 30 to 60 m; North Middle Shelf, 30 to 60 m

and high relief; Deep Middle Shelf, 60 to 140 m; and Deep Shelf, 140 to 200 m. Species

abundance, biomass, and diversity for benthic communities were lowest in areas west of

Cape San Bias. High microbial biomass and foraminiferans indicated environmental stress.

In general, the area east and south of Cape San Bias was considered high in species

diversity and relatively stable. The Florida Middle Ground supported diverse communities

which exhibited tropical affinities. Epibiota of this area were subjected to natural

perturbations (i.e., Hurricane "Eloise") and proved to be resilient. Macroalgae were usually

detached by severe storms.

Trace metal concentrations in sediments were variable. Iron used as a mineralogical

indicator in predictive plots (iron vs. all other metals) showed no evidence of present-day

pollution. Trace metal concentrations were variable within and between epifaunal phyla;

corals were the exception, while sponges typified the pattern. Crustaceans and tunicates

concentrated copper and vanadium, respectively; both metals are components of respiratory

pigments.

Hydrocarbon analysis disclosed that MAFLA area sediments are essentially free of

contamination. Exceptions to this were sites south of Mobile, Alabama where stations were

characterized by abundant high molecular weight terrigeneous n-alkanes and low molecular

weight n-alkanes typical of weathered petroleum. Again riverine input was responsible for

these observations. No discernabie changes in either the amounts or composition of

hydrocarbons in the epifaunal samples were detected between stations or seasons. All

hydrocarbons found were biogenic. Some algae did contain hydrocarbons indicative of

petrogenic contamination. These findings were seasonal and apparently related to

circulation patterns and not petroleum residues in the adjacent sediments.

4 Environmental Mapping
At the rig-monitoring site, small benthic forarniniferans indicative of rigorous (i.e., stressed)

conditions were present before drilling operations began. Foraminiferan populations

declined after drilling. Sand, clay, and carbonate levels increased while silt levels decreased

during drilling; these trends reversed following drilling operations. Cuttings were found at

100-rn and 500-rn periphery stations. No significant changes in hydrocarbon content of

sediments occurred between the three monitoring phases. Barium was the only trace metal

with significantly higher concentrations in sediments during and after drilling.

STUDY PRODUCT(S): State University System of Florida, Institute of Oceanography.

1977. Baseline Monitoring Studies, Mississippi, Alabama, Florida, Outer Continental Shelf

1975-1976. A final report for the U.S. Department of the Interior, Bureau of Land

Management Gulf of Mexico OCS Office, New Orleans, LA. Vol. I (Executive Summary) -

NTIS No. PB-282-801; Vol. II (Introduction and Methods) - NTIS No. PB-282-802; Vol. III

(Results) - NTIS No. PB-282-803; Vol. IV (Discussion) - NTIS No. PB-282-804; Vol. V

(Geophysical Investigations for Biolithologic Mapping of the MAFLA-OCS Lease Area) - NTIS

No. PB-282-806; Vol. VI (Rig Monitoring) - NTIS No. PB-282-805. Contract No.

08550-CT5-30.

STUDY TITLE: MAFLA Environmental Monitoring Program.

COMPLETION DATE OF REPORT: June 1977.

CUMULATIVE PROJECT COST: $3,872,317.

KEY WORDS: Eastern Gulf; Central Gulf; baseline; hydrocarbons; trace metals; sediment;

water column; tissue; Mississippi; Alabama; Florida; macrofauna; meiofauna; maps;

zooplankton; histopathology; shelf; DeSoto Canyon; faunal zones; biology; geology;

monitoring.

Environmental Mapping 5
'a. LOUISIANA MORGAN CITY CINTRAL GULF OF 14(XICO (OION MISS. Ad' ULFJORJ - TRANSECTS SAMPLED DURING THE MAFLA ENVIRONMENTAL MONITORING PROGRAM, FY 1076. o z O 

o 16 60 76 00 

I I I I I 
REPORT TITLE: Eastern Gulf of Mexico Marine Habitat Study.

MMS PUBLICATION NUMBER: Contract No. AA551-CT8-22.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico.

BACKGROUND: In preparation for Oil and Gas Lease Sale 65 (October 1 978), the

U.S. Department of the Interior sponsored several biological and geological studies on the

continental shelf offshore west Florida. Results of these studies showed that several areas

contain features that favor accumulation of marine biota by providing substratum for

attachment of benthic epibiota and shelter and food for demersal fishes. This study was

funded to identify and delineate such areas so that they could be considered for further

study and/or protection from possible effects of offshore oil and gas activities.

OBJECTIVES: (1) To identify and delineate marine benthic habitats in 49 lease blocks

located offshore west Florida that were included in Lease Sale 65.

DESCRIPTION: Two cruises were conducted during July-August 1 978 to provide data for

mapping of geophysical and biological features of 49 lease blocks in the eastern Gulf of

Mexico. The blocks included 3 in the Pensacola Area, 1 7 in the Destin Dome Area, 5 in the

Tarpon Springs Area, 4 in the Elbow Area, 8 in the St. Petersburg Area, and 12 in the

Charlotte Harbor Area. The first cruise involved collection of geophysical data within each

block using a precision depth sounder, dual side-scan sonar, and high resolution subbottom

profilers. East-west survey lines were spaced at 0.2-km intervals, and north-south lines at

2.4-km intervals; the survey grid for each block was designed to complement that of

previous geophysical surveys. The second cruise was conducted to provide visual "ground

truth" for habitat delineations and to allow a description of associated biota. Twenty-three

transects were selected following a review of geophysical data. Transects were surveyed

using a towed television/still camera system in conjunction with navigational and

bathymetric instrumentation.

For mapping purposes, the 49 blocks were grouped into 10 "areas," or sets of contiguous

blocks. These were: Area 1--Pensacola Area Blocks 884, 928, and 972, and Destin Dome

Area Block 4; Area 2--Destin Dome Area Blocks 313, 314, 357, and Dome Area Blocks 529,

573, 574, 618, 661, and 662; Area 4--Destin Dome Area Blocks 473, 474, 518, 519, 562,

and 563; Area 5--Tarpon Springs Area Blocks 233, 234, 277, 278, and 279; Area 6--Elbow

Area Blocks 567, 609, 696, and 697; Area 7--St. Petersburg Area Blocks 661, 662, 705,

and 706; Area 8--St. Petersburg Area Blocks 753, 754, 797, and 798; Area 9--Charlotte

Harbor Area Blocks 143, 144, 145, 187, 188, and 231; and Area 10--Charlotte Harbor Area

Blocks 583, 584, 627, 628, 671, 672, 715, and 716.

Navigational post-plot maps (scale: 1:48,000) were produced for each group. A second set

of maps (scale:1:48,000) was prepared to show bathymetry and seafloor characteristics for

each group. Six categories of seafloor type were assigned: pinnacles, hard bottom,

scattered hard bottom, coarse bottom, bedforms, and soft bottom. A third set of maps

(scale:1:24,000) presented geologic cross sections for each group.

Environmental Mapping 7
SIGNIFICANT CONCLUSIONS: The study successfully mapped the distribution of seafloor

types within each lease block and provided descriptions of the associated biota at selected

locations. Further study to assess and describe potentially sensitive and valuable habitats

was recommended for 6 of the 10 groups of blocks surveyed.

STUDY RESULTS: Soft bottom (thick sand or silt) was the most widespread seafloor type,

but coarse bottom (soft bottom with a surface rubble layer), hard bottom (low-relief, often

scattered and/or partially buried outcrops), and high-relief pinnacles were locally abundant in

some blocks. The biota associated with hard bottom and pinnacles typically included

(depending on location) sea feathers and fans, hard corals, sponges, encrusting coralline

algae, starfishes, sea urchins, and a variety of bottom fishes. The biota was sparse where a

silt or sand veneer partially covered the hard substrate, as in several of the Destin Dome

Area blocks. The most luxuriant and diverse epibiota was noted in association with large

areas of scattered low-relief (<2 m) carbonate outcrops in Charlotte Harbor Area Blocks

143, 144, 145, and 188.

Locations recommended for further study included: areas of extensive pinnacles (up to 12 m

relief) in Destin Dome Area Blocks 573, 574, and 661; localized carbonate outcrops (up to

11 m relief) in Destin Dome Area Blocks 473, 518, and 562; extensive hard-bottom areas in

Tarpon Springs Area Blocks 233, 234, 277, 278, and 279; small (<2 m relief)

outcrops in portions of Elbow Area Block 567; areas of scattered, low-relief, limestone

outcrops in St. Petersburg Area Blocks 661, 662, 705, and 706; and extensive areas of

scattered, low-relief (<2 m) outcrops in Charlotte Harbor Area Blocks 143, 144, 145, and

188.

STUDY PRODUCT(S): Woodward-Clyde Consultants. 1979. Eastern Gulf of Mexico

Marine Habitat Study. A final report for the U.S. Department of the Interior, Bureau of Land

Management Gulf of Mexico OCS Office, New Orleans, LA. Vol. I (Technical Report) - NTIS

No. PB294-152; Vol. II (Maps and Cross Sections) - NTIS No. PB294-153; Vol. III

(Operations Report) - NTIS No. PB8O-164122. Contract No. AA551-CT8-22.

STUDY TITLE: Eastern Gulf of Mexico Habitat Mapping Study.

COMPLETION DATE OF REPORT: January 1979.

CUMULATIVE PROJECT COST: $373,225.

KEY WORDS: Eastern Gulf; biology; geology; geophysical; habitat; maps; videotapes;

photographs; hard-bottom.

8 Environmental Mapping
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LEASE BLOCK AREAS SURVEYED DURING THE EASTERN GULF OF MEXICO HABITAT MAPPG STUDY.

,
REPORT TITLE: Florida Big Bend Seagrass Habitat Study.

MMS PUBLICATION NUMBER: MMS 85-0088.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico.

BACKGROUND: The crescent-shaped portion of Florida's west coast from Ochlockonee

Bay south to Tarpon Springs is referred to as the Florida Big Bend. The expanse of

continental shelf area within the Florida Big Bend is important to fisheries and environmental

interests. When this area became the focus of oil and gas developers, the State of Florida

indicated that the lack of information on live-bottom and seagrass distribution within the

area would not permit responsible management of exploratory activities. Consequently, the

U.S. Department of the Interior initiated the Florida Big Bend Seagrass Study to provide

supporting data for development of biological stipulations and evaluation of lease block

specific plans of exploration or development.

OBJECTIVES: (1) To inventory and map seagrass beds in the Florida Big Bend area by

combining aerial remote sensing and extensive ground truthing data; (2) to determine the

seaward extent of major seagrass beds within the study area; and (3) to classify and

delineate major ecological habitat types in the study area.

DESCRIPTION: The study area encompassed approximately 1.5 million ha of seafloor

extending from the coastline to the 20-rn isobath. The study was conducted in three parts:

(1) a pre-overflight ground truthing cruise; (2) a remote sensing overflight encompassing the

study area; and (3) a post-overflight ground truthing cruise to verify interpretation of remote

sensing data. During the first cruise (Cruise 1) conducted from 24 October to 1 November

1 984, 1 ,232 km of seafloor between the 10- and 20-m depth contours were surveyed using

a towed underwater television system. Navigational fixes consisting of Loran-C time delays

and bottom-type descriptions were recorded at 5-mm intervals along the transects.

Additionally, 50 signature control stations ranging in water depths from 3 to 23 m were

established to assist aerial photographic interpretation in locations of known seagrass

coverage. At each station, large floating targets were deployed; divers then took

quantitative (343.6 cm2) and qualitative 35-mm photographs of the seafloor under the

targets to estimate seagrass density and species composition. Aerial overflights were made

between 30 October and 1 5 November 1984 along 26 north-south flight lines. Photographs were taken using 23 cm x 23 cm color print film. The scale on all photographs was

1:40,000. During Cruise 2 conducted from 1 9 to 27 February 1985, nine additional

transects (1 74 km) were surveyed using towed divers and underwater television. Eleven of

the 50 signature control stations established during Cruise 1 were resampled using the same

methods employed during the earlier cruise. Aerial photographs were analyzed

stereoscopically, and seagrass beds were classified by density (dense, sparse, and patchy).

Due to signature similarities between seagrass beds and low relief coral, sponge, and

gorgonid assemblages frequently seen between them, live bottom could not be

differentiated from seagrass habitat at the 1:40,000 imagery scale.

SIGNIFICANT CONCLUSIONS: Within the Florida Big Bend study area, 16% of the area

was described as dense seagrass beds, 33% as sparse seagrass beds, and 1 9% as patchy seagrass beds. Seagrass associations occurred in two general zones based on depth. In

Environmental Mapping 11
waters shallower than 10 m, dense associations of turtle grass, manatee grass, and

shoalgrass provided dense images in the aerial photography. Seaward of this zone, sparse

associations of seagrasses, macroalgae, and live bottom were identified extending to at

least the 23-rn depth contour. The extended nature of this sparse, offshore zone was

considered a unique feature of the Florida Big Bend area zonation pattern. Seasonal

variation in seagrass blade density and species composition was observed at the offshore

signature control stations. Little information is available concerning the ecology of the

fringing zone seagrass beds of the Florida Big Bend area.

STUDY RESULTS: Approximately 1 .5 million ha were mapped during overflights of the

Florida Big Bend study area. Two maps were produced: one at 1:40,000 scale and another

at 1:250,000 scale. The second map was a composite, produced to be superimposed on

existing Minerals Management Service Protraction Diagrams. Results from combined aerial

mapping and ground truthing delimited 232,893 ha of dense seagrass beds; 498,034 ha of

sparse seagrass beds; and 279,722 ha of patchy seagrass beds within the study area.

On a broad scale, the Florida Big Bend seagrass stands exhibited zonation typical of

southern Florida or Caribbean seagrass beds. An inshore association of turtle grass

(Thalassia testudinum), manatee grass (Syringodium fiiforme), and shoalgrass (Halodule

wrightii occurred in water depths less than 10 m. Turtle grass and manatee grass formed

dense beds that were easily detected by aerial photographs. At the seaward margin of

these dense beds, an overlap area consisting of five species (manatee grass, turtle grass,

and shoalgrass, as well as Halophila decipiens and H. engelmanni) was detected. Offshore,

from 10 rn out to at least 23 m a sparse fringing zone occurred. This zone was composed

of a mixed association of seagrasses, macroalgae, and live bottom. The only true

seagrasses present were the Ha/ophila species.

Blade density determined from the nearshore association ranged from 41 to 309 blades m2.

In the offshore association, blade densities ranged from 374 to 2,657 blades m2. Blade

density was not indicative of bottom coverage by seagrasses within the two zones. Blade

densities at 9 of the 11 signature control stations resampled during Cruise 2 were 50 to

90% lower and H. decipiens was completely absent. Temperature, light, and wave action

probably contributed to the observed spatial and seasonal patterns in the grass beds.

STUDY PRODUCT(S): Continental Shelf Associates, Inc. and Martel Laboratories, Inc.

1985. Florida Big Bend Seagrass Habitat Study. A final report for the U.S. Department of

the Interior, Minerals Management Service Gulf of Mexico OCS Region, Metairie, LA.

Contract No. 14-12-0001-30188. 89 pp.

Continental Shelf Associates, Inc. and Martel Laboratories, Inc. 1 985. Florida Big send

Seagrass Habitat Study Photographic Atlas. A final report for the U.S. Department of the

Interior, Minerals Management Service Gulf of Mexico OCS Region, Metairie, LA. Contract

No. 14-12-0001-30188. 6 pp. + 557 plates.

STUDY TITLE: Florida Big Bend Seagrass Habitat Study.

COMPLETION DATE OF REPORT: December 1985.

1 2 Environmental Mapping
CUMULATIVE PROJECT COST: $385,946.

KEY WORDS: Eastern Gulf; Florida Big Bend; biology; seagrasses; inventory; maps; aerial

photography; survey; photographimetric technique; benthic photographs; habitat; zonation;

hard-bottom.

Environmental Mapping 1 3
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ACCESS NUMBER:30 188

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REPORT TITLE: Assessment of Hurricane Damage in the Florida Big Bend Seagrass Beds.

MMS PUBLICATION NUMBER: MMS 87-0001.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico.

BACKGROUND: During fall and winter of 1984 and 1985, the Minerals Management

Service (MMS) funded a seagrass mapping study of the Florida Big Bend area. Following the

passage of major hurricanes in summer 1985, the MMS decided to sponsor a follow-up

study to assess hurricane impacts and seagrass recovery in the area. New field data were

collected during a survey in August 1986, and all previously collected data on seagrasses of

the Big Bend area were reviewed and compared with new data sets.

OBJECTIVES: (1) To provide follow-up data to those collected in 1984 and 1985 during

the Florida Big Bend Seagrass Study; and (2) to assess hurricane damage and seagrass

recovery in the area.

DESCRIPTION: The study area encompassed approximately 1 .5 million ha of seafloor

extending from the coastline to the 20 m isobath. Two approaches used during the

previous study were repeated approximately one year after the passage of major

hurricanes. The first involved qualitative observations made along transects surveyed by

divers and/or television. The second involved photographic sampling at selected stations in

the area. During Cruise 1 of the previous survey, conducted from 24 October to

1 November 1984, 232 km of seafloor between the 10- and 20-rn depth contours were

surveyed using a towed underwater television system. During Cruise 2, conducted from 1 9

to 27 February 1985, nine additional transects (174 km) were surveyed using towed

divers/television. During the previous study, 50 signature control stations ranging in water

depths from 3 to 23 m were established to assist aerial photographic interpretation in

locations of known seagrass coverage. Quantitative photographs of the seafloor were taken

at these stations using a Nikonos 35-mm underwater camera with a 0.03 rn2 framer.

Counts of seagrass blades in each photograph provided estimates of blade density.

From June through October 1985, a seagrass monitoring program was conducted in

Gainesville Area Block 707. The aim of this study was to monitor impacts of discharged

drilling muds on live-bottom areas and deep seagrass communities. Data collected during

this study, particularly dry weight biomass estimates of seagrass leaves (Ha/ophila dec/p/ens

and H. eng/emanni) and seagrass density estimates from photoquadrats, were used to

augment the effort.

The new field surveys were conducted between 14 and 19 August 1986. Days of sampling

signature control stations were alternated with days of television/diver transect surveys.

Most transects were surveyed with both diver and television in the water at the same time.

Navigational fixes consisting of Loran-C time delays and bottom-type descriptions were

Environmental Mapping 1 5
recorded at 5-mm intervals along the transects. Twenty of the original signature control

stations were resampled photographically in August 1986. Four of these stations were live

bottom, and a live-bottom reference station from the monitoring program was also

resampled. At this station 10 staked quadrats were sampled photographically with a 0.1 m2

framer.

SIGNIFICANT CONCLUSIONS: It was apparent that seagrass, algal, and live-bottom

communities on the west Florida shelf are resilient to storm impacts. Areas of Halophila sp.

denuded by Hurricane "Elena" in 1985 appeared fully recovered after the 1986 growing

season. Live-bottom organisms, particularly octocorals, seem to be adapted to withstand

both wave energy and sand scour associated withstorms.

STUDY RESULTS: Resurveyed transect data were compared with the original survey

data. Little change in percent cover by major habitat types was evident. Along one

transect, there was an observed increase in seagrass coverage; however, this was

apparently due to an extension of the transect length during the second survey and not to

increased seagrass cover.

Comparisons of 1984 and 1986 data from the H. decipiens stations showed leaf density and

biomass were higher at some stations and lower at others, but the mean values were

comparable. There was no demonstrable relationship between standing stock estimates and

hurricane tracks that could be shown. Three of the signature control stations dominated by

H. engelmanni in October 1 984 had only sparse Ha/ophila shoots and rhizomes present

during August 1 986. The elimination of H. enge/manni at these stations was not

considered a hurricane impact. Dense nearshore beds, composed of mixed stands of turtle

grass (Tha/assia testudinum), manatee grass (Syringodium fiuforme), and shoalgrass

(Halodule wrightii, showed no noticeable changes between the 1 984 and 1 986 surveys.

Biotic coverage and gross taxonomic composition of the epifaunal communities at the

live-bottom stations were comparable between 1 984 and 1 986 surveys.

In 1985, when divers visited the monitoring site in the Big Bend area where Hurricane

"Elena" had passed through eight days earlier, tremendous destruction of seagrasses,

macroalgae, and sessile invertebrates was found. Considerable sediment movement had

also occurred in some places. The August 1 986 survey, conducted approximately one year

after the passage of the hurricane, showed that seagrasses were again present in areas that

had been completely denuded. The seagrass/algal and live-bottom areas of the west Florida

shelf were considered resilient to the occasional passage of major hurricanes.

STUDY PRODUCT(S): Continental Shelf Associates, Inc. 1987. Assessment of Hurricane

Damage in the Florida Big Bend Seagrass Beds. A final report for the U.S. Department of

the Interior, Minerals Management Service Gulf of Mexico OCS Region, New Orleans, LA.

Contract No. 14-12-0001-30188. 95 pp.

STUDY TITLE: Florida Big Bend Sea Grass Habitat Study.

COMPLETION DATE OF REPORT: February 1987.

CUMULATIVE PROJECT COST: $386,998.

1 6 Environmental Mapping
KEY WORDS: Eastern Gulf; Florida; Big Bend; biology; seagrasses; hurricane; recovery;

observations; benthic photographs; videotapes; density; hard-bottom; West Florida Shelf.

Environmental Mapping 1 7
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REPORT TITLE: Mapping of Submerged Vegetation Using Remote Sensing Technology.

MMS PUBLICATION NUMBER: Contract No. AA551-1A8-27.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico.

BACKGROUND: Seagrasses have a potential role as indicators of the impact of man's

activities on estuarine and coastal ecosystems. Information on changes in seagrass

distribution, abundance, and diversity can aid in decisions and guidelines for coastal zone

management. However, it is first necessary to develop a technique to provide distribution

and abundance data accurately and economically. Aerospace color remote sensing could

satisfy this requirement. This project was designed to investigate the potential for utilizing

this technology with modifications for mapping seagrass distributions.

OBJECTIVES: (1) To evaluate a 21-channel solid state array spectroradiometer (SAS);

(2) to determine if common seagrasses and other bottom types can be detected and

differentiated with high resolution spectral data; (3) to develop and document applicable

computer algorithms for processing, analyzing, and classifying spectral data into charts of

seagrass distribution; and (4) to determine any deleterious effects of water depth and

optical properties on spectral signatures of seagrasses.

DESCRIPTION: Two types of data were collected. The first type involved surface truth

data collected from 20 stations in St. Joseph Bay, Florida on 17 May 1978. Remote

sensing data were collected on 18 and 19 May 1978. Surface truth data were used to

identify indigenous seagrasses and to describe respective environments. The remotely

sensed data were collected from a Beechcraft E-18S equipped with a 70-mm Hasselblad

camera, Zeiss RMK 15/23 camera with a 15.24-cm focal length lens, a RS-18 multispectral

scanner, and the SAS. Flights were flown at 1 ,520 m for the RS-1 8 and at 3,050 m for the

SAS data collection efforts. Remote sensing data were analyzed using spectral information

from the training fields and a discriminant function analysis computer program to develop

algorithms used in a supervised pattern recognition approach. Secondarily, spectral data

were combined with supervised data groupings in a hybrid supervised-unsupervised

maximum likelihood pattern recognition approach.

SIGNIFICANT CONCLUSIONS: The project demonstrated the ability to use remotely

sensed data and advanced computer techniques to map monospecific benthic vegetation in

a fairly stable environment. However, the project was unsuccessful in evaluating the

feasibility of mapping multispecies benthic vegetation assemblages in complex open coastal environments.

STUDY RESULTS: The project failed to produce a usable classification product for the

user community. It was determined that several modifications were needed before the SAS

could be considered an operational sensor, including: (1) a wider field of view so that

ground track and aircraft attitude are not so critical; (2) a greater dynamic range for the

signal in order to accommodate varying signal levels encountered in a mission; (3) a higher data rate to lower the aspect ratio thereby giving better ground resolution; (4) inclusion of

aircraft attitude data in the SAS data stream to allow correction of the data for pointing errors; and (5) overall system noise reduction to achieve true 8-bit resolution.

Environmental Mapping 1 9
Qualitative comparison of the classification results with ground truth data led to the

conclusion that the classification maps were detailed and accurate. However, some

imperfections were noted in the maps. Comparisons were made of seagrass distributions in

the bay using historical data and the remotely sensed information from this study. The

estimate of 2,300 to 2,400 hectares of vegetation covering the bay measured in this study

compared well with an estimate of 2,560 hectares reported in 1972. This supported a

finding that the bay macroplant community distribution is relatively stable on an annual

basis.

The multispectral scanner sensor used in this investigation offered advantages over surface

based mapping or mapping from conventional aerial photography in terms of resolution of

different water depths, bottom types, and types and densities of submerged vegetation

coverage.

STUDY PRODUCT(S): Savastano, K. J., K. H. Faller, L. W. McFadin, and H. Holley. 1981.

Mapping of Submerged Vegetation Using Remote Sensing Technology. A final report by the

National Marine Fisheries Service, Southeast Fisheries Center for the U.S. Department of the

Interior, Bureau of Land Management Gulf of Mexico OCS Office, New Orleans, LA. NTIS

No. PB82-163072. NOAA Technical Memorandum NMFS-SEFC-73. Contract No.

AA551-1A8-27. 68 pp.

STUDY TITLE: Mapping of Seagrasses by Remote Sensing in the Eastern Gulf of Mexico.

COMPLETION DATE OF REPORT: 1981.

CUMULATIVE PROJECT COST: $5,000.

KEY WORDS: Eastern Gulf; Florida; baseline; seagrasses; aerial photography;

photographs; subtidal; St. Joseph Bay; estuarine; coastal zone; maps; historical review;

ma crophytes.

20 Environmental Mapping
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PHYSICAL OCEANOGRAPHY

Winds, waves, and currents in and around areas of oil and gas activities determine the

extent of pollutant transport, the dispersion of waste products, and the expected

impacts on nearby biologically sensitive areas. A good understanding of the physical

nature of a system is basic to other primary disciplines. Circulation affects recruitment

of juvenile organisms, the transport of smothering sediments (including muds and

cuttings), and the flushing of waste material from the region. A good understanding of

the physical dynamics of a region is necessary to support other disciplines, including

biological, chemical, engineering, and geological, and to support diagnostic and

predictive modeling efforts. An important use of physical oceanographic data is an

input to the Oil Spill Risk Analysis performed by MMS.

Physical Oceanography 23
REPORT TITLE: Southwest Florida Shelf Circulation Model.

MMS PUBLICATION NUMBER: Contract No. AA851-CTO-72.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico.

BACKGROUND: The southwest Florida shelf has been the subject of environmental

scrutiny since the U.S. Department of the Interior (USD01) made lease blocks available for

oil and gas exploration. There was an attendant need to have a predictive circulation model

that would forecast the possible transport of pollutants associated with petroleum

activities. This study incorporates available hydrographic data for use in such a model

applicable to the southwest Florida shelf.

OBJECTIVES: (1) To adapt an existing numerical hydrodynamic model to the shelf; (2) to

test the model with appropriate existing data from the shelf; (3) to recommend additional

data collection efforts needed to improve the models effectiveness; and (4) to document

the model for use by USD01 personnel.

DESCRIPTION: This study was comprised of four separate phases: (1) Literature review

and data search; (2) Model modifications and basic sensitivity studies; (3) Model verification

and tuning; and (4) Prediction of seasonal circulation patterns. In Phase 1, existing literature

pertaining to the Loop Current or the West Florida Shelf circulation was reviewed for raw

data needed for input to the model. Phase 2 consisted of the following model

modifications: provision for model forcing due to horizontal density gradients, improvement

of lateral shear stress parameterization, selection of suitable grid system for the West

Florida Shelf, provision for a spatially variable Coriolis parameter, and reorganization of the

program coding into modular units. Phase 3 involved comparisons of model simulations

with available real time data. Wind data were input into the model, then results were

compared to low-frequency, real-time velocity and sea level data. Model parameters were

then adjusted to achieve a best fit between model results and data. At the completion of

this phase, the model was considered theoretically sound and able to accurately simulate

West Florida Shelf dynamics. During Phase 4, long-term reproductions of shelf circulation

were accomplished by separately modeling the effects of the Loop Current, differential

heating, and wind. These results were superimposed to produce a composite atlas of

residual circulation.

To accommodate model requirements, the study area was from 30°N Lat, south to the

Florida Keys, and west to the 200-rn isobath. This area encompasses the entire West

Florida Shelf.

The basic model is a primitive, diagnostic model based on momentum and continuity

equations. A weighted residual technique used in model formulation eliminates vertical

dependency of the velocity components. All significant forcing mechanisms are included:

Coriolis force, horizontal density gradient, surface pressure gradients, wind stress, bottom

friction, horizontal and vertical eddy viscosity coefficients, and lateral shearing stresses from

the Loop Current.

Physical Oceanography 25
SIGNIFICANT CONCLUSIONS: Additional data, especially pertaining to circulation

patterns, is needed to advance the understanding of West Florida Shelf hydrodynamics.

Comparisons of model simulations with available data showed that hindcasts were good for

surface elevation and current velocity. A hindcast of winter 1973 data predicted eddies

propagating from the Loop Current shoreward. Seasonal (long-term) simulations of surface

currents predicted southerly flow during winter and northerly during spring and summer;

these simulations agreed with available drift bottle data. Actual model parameterization for

the Loop Current was impeded by lack of current meter data.

STUDY RESULTS: Circulation in the eastern Gulf of Mexico is dominated by the Loop

Current; annual cycles of this current are subject to considerable variability. The Loop

Current abuts the lower portion of the West Florida Shelf during most of the year, and

during northward incursions it abuts the entire shelf. Cyclonic eddies, meanders, and

tongues from the Loop Current often traverse the shelf. Spin-off eddies may be 200 km in

length and have periods of 1 5 days; short-term hydrographic measurements recorded over

similar length scales as the eddies could be serious biased. Lateral shear mechanisms

generated by the Loop Current also contribute to shelf circulation. Maximum tidal currents

on the shelf were 10 cm s1, causing advection of about 1 km. Thus, tidal forcing, only

important as an advective mechanism near the coastline, was not included in the model. In

Phase 2, a grid composed of 12 by 24 elements (30 km on a side) with land, seaward, and

lateral open boundary types was developed. Bathymetry was limited to 200-m which did

not affect simulations of on-shelf circulation, another modification of slope bathymetry in

the southwest corner of the grid was also accomplished with little effect on model output.

Sensitivity studies suggested that reasonable values for drag coefficient (bottom friction)

and horizontal eddy viscosity range from 0.02 to 0.08 cm s' and io to iO cm s1,

respectively. Surface phenomena (wind-induced flow, surface velocity, and coastal surface

elevations) were insensitive to changes in drag coefficients, but velocities lower in the water

column were sensitive to drag coefficient changes. Addition of a boundary current with an

assumed magnitude of 100 cm s1 along the western margin of the grid generated spin-off

eddies depending on where the current was imposed. By temporally varying the boundary

current, northward migrating barotropic waves were generated. Stratification decreased

currents in the lower layer and increased currents in the mixed layer. During Phase 3,

comparisons were restricted to synoptic time periods of 2 to 30 days using data sets

(current velocity and surface elevation) collected during February-March 1973 and

February-March 1978. From the 1978 data, the model predicted real time residual currents

usually to within 5 cm s1 over a range of 40 cm s1, and surface elevations to ±2 cm over a

range of 40 cm. Discrepancies between modeled and observed currents were due to

measurement error, inadequately modeled wind field, unmodeled effects of the Loop

Current, or horizontal density gradients and not to an inadequate choice of model dissipation

coefficients. For winter 1973, surface elevations were modeled within 5 cm in amplitude

and 5 h in phase. The model underestimates the surge peaks by about 10 cm. Forcing by

the Loop Current over-predicted the surface elevations using a barotropic eddy wave. Using

an alternative lateral shear mechanism to model the Loop Current, reasonable comparisons

to observed current data were given. Current meter data were affected by the passage of frontal systems. Summer 1 974 observed surface elevations were consistent with modeled

elevations but the phase was consistently in error. Complications with the wind field was

also a problem during simulations.

26 Physical Oceanography
During Phase 4, seasonally averaged wind fields, density gradients, and Loop Current

effects were modeled to achieve a realistic shelf circulation model. Winds were divided into

three seasons: fall-winter with northeasterly winds of 4.5 m s1; spring with

south-southeasterly winds of 5.5 m s1; and summer with southeasterly winds of 4 m s.

Modeled fall-winter surface currents were about 10 cm s1 and displayed a net movement to

the south, implying that drifters will be entrained in the Loop Current and advected to the

Florida Keys or the eastern coast of the United States. Spring surface currents were about

3 cm s1 and displayed net movement to the north. Summer surface currents were less than

1 cm s1 and exhibited net movement to the north.

STUDY PRODUCT(S): Cooper, C. 1982. Southwest Florida Shelf Circulation Model. A

final report by New England Coastal Engineers, Inc. for the U.S. Department of the Interior,

Minerals Management Service Gulf of Mexico OCS Office, Metairie, LA. Vol. I (Technical

Report) - NTIS No. PB84-1 1 3240; Vol. II (Appendices - Programmer's Guide) - NTIS No.

PB84-129857; Vol. III (Data Report) - NTIS No. PB84-1 13364.

Contract No. AA851-CTO-72.

STUDY TITLE: West Florida Shelf Circulation Modeling Study.

COMPLETION DATE OF REPORT: October 1982.

CUMULATIVE PROJECT COST: $233,455.

KEY WORDS: Eastern Gulf; West Florida Shelf; Loop Current; physical oceanography;

hydrodynamics; modeling; currents; meteorology.

Physical Oceanography 27
QALV$ TON L :4W ORLAN$ MOe I.E 2' PANAMA CITY 

I 200 WESTERN CENTRAL GULF OF MEXICO REGION TROPIC OF CANCER GENERAL AREA FOR THE SOUTHWEST FLORIDA SHELF CIRCULATION MODELING STUDY. EASTERN 22STATUTE 11ILC 0 50 00 F I I KII.OW(TERS 0 00 100 50
REPORT TITLE: Gulf of Mexico Satellite Radar Altimetry.

MMS PUBLICATION NUMBER: Contract No. AA85 i-lAO-i 1.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico;

Western Gulf of Mexico.

BACKGROUND: The GEOS-3 satellite, the first dedicated radar altimeter used to obtain

oceanographic data, was employed in an altimetry study of the South Atlantic Bight.

Principal data products were ocean dynamic heights, significant wave heights, and surface

wind speeds. In the present study, GEOS-3 in conjunction with another satellite, SEASAT,

gathered similar information for the Gulf of Mexico.

OBJECTIVES: (1) To provide satellite altimetry information for the Gulf of Mexico; and

(2) to compare results (sea surface elevation, significant wave heights, surface wave

heights) from two satellites over the same area.

DESCRIPTION: Data from passes of each satellite over the Gulf of Mexico from Spring

1 975 to Fall 1978 for GEOS-3 and from Spring to Fall 1 978 for SEASAT were recorded and

analyzed. GEOS-3 operates on a frequency of 1 3.9-GHz with both global and intensive

mode. The intensive mode produces a compressed pulse of 12.5 ns and provides

measurements with precision of about 20 cm for a is average. This configuration yields a

footprint 3.6 km wide and ii km along the track from an orbit of 840 km in altitude, an

inclination of 115°, and a period of 101.8 mm. SEASAT was also designed to operate at a

frequency of 13.9 GHz but was compressed to 3 ns providing a precision of about 10 cm

for a P average. The SEASAT footprint configuration was 1 .6 km wide and 12 km along

the track from an orbit of 800 km in altitude, an inclination of 108°, and a period of

100.75 mm. Analytic procedures and algorithms used for data reduction were essentially

the same for both satellites; sea surface elevation profiles were resolved on a 30-minute

geoid of the Gulf of Mexico; this method resulted in considerable resolution variability. To

determine overall variability associated with the geoid, a three-year mean topographic map

and a three-year standard deviation map were generated using all satellite passes over the

Gulf of Mexico by both satellites. These topographic maps are then the average of the

pass-by-pass variation calculated over a 1 5-minute grid over the entire Gulf of Mexico and

processed seasonally. Significant wave height was computed aboard SEASAT at 10 s_i,

reduced to 4.6 s', while GEOS-3 was computed on the ground at major frame rates of

3.2 s_i for high data rates and 2.0 s_i for low data rates. Surface wind speeds were

calculated using two formulae; correction factors were applied for different wind speeds.

Data rates for SEASAT and GEOS-3 were the same as for the significant wave height data.

Anomalous GEOS-3 data passes recorded during July, August, September, and October

1 975 were omitted from the final data set.

SIGNIFICANT CONCLUSIONS: The 30-minute grid contributed to appreciable lack of

dynamic height geoid resolution and variation maps were biased by the large number of

passes recorded during the last few months of the study. Only large dynamic height

features could be determined. Significant wave height was generally small for the Gulf of

Mexico; only in Winter 1976 did mean wave height exceed 2 m. Surface wind speed data

exhibited reduced variability, and distinct seasonal fluctuations were observed.

Physical Oceanography 29
STUDY RESULTS: The gravimetric geoid method used to extract the residuals from the

altimeter heights was inadequate; geoidal undulations of small horizontal scales but ranging

in amplitude from 1 to 4 m were poorly modeled and caused inaccurate results in the

dynamic height analyses. Surface topography maps were only accurate if a sufficient

number of passes had been recorded for that particular map. Of 1 5 maps analyzed, 2 were

totally unusable because of poor coverage, 8 showed sufficient coverage for the Eastern Gulf but not for the Western Gulf, and 5 were excellent with respect to coverage. Only

large surface features could be accurately discerned; features in excess of 1 50 cm were

due to dynamic heights. Significant wave height displayed relatively low values from April 1 975 to October 1 978. A mean value of 2.3 m recorded in January 1 976 was the only

instance where mean wave height exceeded 2.0 m. Variance was generally constant

during the study period. Altimeter readings for waves smaller than 2.0 m tend to be noisy

thus precluding quantitative representation of this data. Wind speed measurements were

most reliable, and distinct seasonal variations were seen. Highest values were recorded

during winter months (8.5 m s1 in November 1977) and lowest values were recorded during

summer months (3.3 m s1 in July 1976). There were no appreciable differences in wind

speeds between the Eastern or the Western Gulf of Mexico.

STUDY PRODUCT(S): Parra, C. G., R. G. Forsythe, and C. L. Parsons. 1981. Gulf of

Mexico Satellite Radar Altimetry. A joint report by the National Aeronautics and Space

Administration and the U.S. Department of the Interior, Bureau of Land Management Gulf

of Mexico OCS Office, New Orleans, LA. NTIS No. N81-33760/2. Contract

No. AA851-IAO-1 1. NASA Tech. Memo. 73295. 230 pp.

STUDY TITLE: Gulf of Mexico Satellite Oceanography Study.

COMPLETION DATE OF REPORT: August 1981.

CUMULATIVE PROJECT COST: $223,000.

KEY WORDS: Eastern Gulf; Central Gulf; Western Gulf; physical oceanography;

meteorology; satellite imagery; seasonality; wave height.

30 Physical Oceanography
CORPUR CHIITI GALVESTON NEW ORLEANS uOaa.E OULFPORT ,o PENSACOLA PANAMA CITY "TAM

20 kILOUfl053 0 50 100 ISO 200 WESTERN CENTRAL GULF OF MEXICO REGION STATUTC IL(S 0 00 00 TROPIC OF CANCER AREA INCLUDED IN THE GULF OF MEXICO SATELLITE RADAR ALTIMETRY STUDY. EASTERN 
REPORT TITLE: Gulf of Mexico Physical Oceanography Program Final Report, Year 4. Vol.

I, Executive Summary; Vol. II, Technical Report.

MMS PUBLICATION NUMBER: MMS 87-0007.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico;

Western Gulf of Mexico.

BACKGROUND: In 1982, the U.S. Department of the Interior initiated a multi-year

investigation of physical oceanographic conditions related to or resulting from deep

circulation patterns in the Gulf of Mexico. During the first, second, and fourth study years,

measurements and interpretation focused on the southeastern Gulf of Mexico with emphasis

on the Loop Current and its interaction with the adjacent west Florida shelf and slope. The

third study year focused on the western portion of the Gulf of Mexico. The present report

includes field measurements from the fourth year and is considered an addendum to the first

and second year report.

OBJECTIVES: (1) To develop a better understanding of conditions and processes

governing Gulf of Mexico circulation; and (2) to provide a data base to be used as initial and

boundary conditions in companion numerical circulation modeling studies.

DESCRIPTION: During the first two study years, data necessary to describe Loop Current

behavior and associated circulation patterns were obtained from Lagrangian drifters, satellite

thermal imagery, regional shipboard hydrographic surveys, moored current meters, and

ships-of-opportunity. The fourth year program continued data collection using current

meters, Lagrangian drifters, and ships-of-opportunity only.

Two drifting buoys equipped with position transmitting instrumentation were used to track

rings. One buoy was deployed on 18 June 1985 in a newly formed warm core ring at

approximately 26°N Lat and 88°W Long; on 18 July 1985, another buoy equipped with a

200-m thermistor string was deployed in another newly formed warm core ring at

approximately 26°24'N Lat and 89°24'W Long. Vertical profiles of horizontal currents

obtained during the previous years. Work using hull mounted acoustic doppler currents

profilers were further analyzed. Current meters were used to measure temperature,

subsurface currents, and pressure. In January 1 985, six moorings were redeployed on the

west Florida shelf and slope. The redeployment of these meters served as a continuation of

field measurements that began in this region in January 1983. Five tautline moorings were

deployed along a heading perpendicular to the west Florida shelf in water depths ranging

from 50 to 3,275 m, while one was placed 1 67 km north on the 1 80-rn isobath. The

ships-of-opportunity program continued to provide information and support the field efforts.

SIGNIFICANT CONCLUSIONS: An anticyclonic feature embedded in the Loop Current was

tracked. This revealed that the basic closed pattern of clockwise rotating water may exist

regularly in that region interior to high speed flow regimes and can develop at least during or

after Loop Current eddy separation. Inertial currents were important to the dynamics of the

west Florida shelf oceanography. They were found to be energetic, with amplitudes often

exceeding magnitudes of mean currents, low-frequency fluctuations, and tides. Nearshore

currents on the west Florida shelf were primarily wind driven.

Physical Oceanography 33
STUDY RESULTS: A buoy was deployed in June 1985 in what was believed to be a

pinched off Loop Current eddy. Actually, separation was not complete and the drifter

travelled 525 km southeast, entrained within the Loop Current, by mid-September 1985.

There were three complete rotations observed before the drifter moved out of the Gulf

through the Straits of Florida. The second buoy was in an actual Loop Current separated

eddy. The rotation velocities decreased as the buoy neared the eddy center. Drifter

velocities ranged from 30 to 90 cm sec1 and appeared to decrease with time. In both

features, the buoys indicated closed circulation. During the hydrographic cruise, 268

hydrographic stations were occupied. These data were obtained on 20 sections, 13 of

which were in the vicinity of the Loop Current boundary and three were through a large cold

perturbation of the Loop Current front. The general pattern had wave-like boundary

features. Higher speed currents were located in a 1 00 to 1 50-km near surface band which

was adjacent to the Loop Current frontal boundary. Maximum speeds near or at the surface

decreased by approximately 50% or more in the upper 250 m. This zone moved laterally

from the shelf break to 100 km seaward of the shelf break.

Inertial currents determined from current meter data on the west Florida shelf were

energetic with peak amplitudes from 15 to 30 cm sec1. Peak amplitudes were thought to

be associated with the pycnocline. Amplitudes were intermittent in space and time and not

well correlated between moorings. Mid-depth maxima of inertial amplitudes were common

at moorings which sampled at the base of the mixed layer. Two hurricanes in 1 985 (Elena

and Kate) had similar tracks and produced sharp peaks of inertial

amplitudes at all sites to a maximum of 42 cm sec1.

Circulation patterns having periods longer than one day were Loop Current- and

wind-forced. Wind signals exhibited a seasonal modulation with a summer minimum and a

fall-winter-spring maximum. The primary signal was related to frontal passage. Nearshore

currents were primarily wind driven. Wind forcing occurred in preferential frequency bands

encompassing periods of 3 to 10 days. There was appreciable wind-current coherence

which was variable with season. The Loop Current boundary moved onshore and offshore

at periods of greater than two weeks.

STUDY PRODUCT(S): Science Applications International Corporation. 1987. Gulf of

Mexico Physical Oceanography Program Final Report, Year 4. Vol. I, Executive Summary. A

final report for the U.S. Department of the Interior, Minerals Management Service Gulf of

Mexico OCS Region, New Orleans, LA. NTIS No. PB88-170402. MMS Report 87-0006.

Contract No. 14-12-0001-29158. 14 pp.

34 Physical Oceanography
Science Applications International Corporation. 1987. Gulf of Mexico Physical

Oceanography Program Final Report, Year 4. Vol. II, Technical Report. A final report for the

U.S. Department of the Interior, Minerals Management Service Gulf of Mexico OCS

Region, New Orleans, LA. NTIS No. PB88-170782. MMS Report 87-0007. Contract No.

14-12-0001-29158. 378 pp.

STUDY TITLE: Gulf of Mexico OCS Physical Oceanography Field Study, Year I, II, and III.

COMPLETION DATE OF REPORT: 1987.

CUMULATIVE PROJECT COST: $5,499,579.

KEY WORDS: Eastern Gulf; Central Gulf; Western Gulf; Florida; Louisiana; Texas; physical

oceanography; Loop Current; currents; satellite imagery; hydrography; survey; shipboard

observations; nutrients; West Florida Shelf; slope; shelf; eddy; wind forcing;

hurricane.

Physical Oceanography 35
colpu' caTI OALVI.$TOH p11w OILIANIguLrpoR'T ,.. SILl PIN$ACOLA PANAMA crTY 25 IILOMflEII 0 10 00 00 100 WESTERN GENERAL STUDY .- AREA BOUNDARY IAUTI p1ILCI 0 50 00 - '1⁄4 CENTRAL GULF OF MEXICO REGION GENERAL STUDY AREA FOR GULF OF MEXICO OCS PHYSICAL OCEANOGRAPHY FIELD STUDY, YEAR 4. FLORIDA SHELF/SLOPE CURRENT METFR ARRAYS :' EA8TERN 1OPICOFCANCEI
REPORT TITLE: Gulf of Mexico Circulation Modeling Study Annual Progress Report,

Year 1.

MMS PUBLICATION NUMBER: MMS 85-0025.

APPLICABLE PLANNING AREA(S): Straits of Florida; Eastern Gulf of Mexico; Central Gulf

of Mexico; Western Gulf of Mexico.

BACKGROUND: Accurate understanding of circulation patterns in the Gulf of Mexico are

essential when predicting dispersal of pollutants or any other transportable contaminants.

Conventional methods of obtaining circulation data are time consuming and costly.

Computer simulations obviate some of the time and expense involved in characterizing or

predicting oceanic circulation patterns. The U.S. Department of the Interior sponsored a

four-year effort to upgrade and test an existing computer model of Gulf of Mexico

circulation patterns that will provide management personnel with quick and reliable

simulations of particular circulation patterns in the absence of field collected data.

OBJECTIVES: (1) To progressively upgrade in modest increments an existing numerical

ocean circulation model of the Gulf of Mexico so that the final model has horizontal

resolution of about 10 km and vertical resolution approaching 1 to 10 m in the mixed layer,

10 m at the thermocline, and 100 m in deep water.

DESCRIPTION: During this four-year project, the validity of the upgraded model will be

continuously tested, and velocity field time series delivered periodically based on the most

realistic simulation of Gulf circulation available. Experiments during this first year were with

the existing NORDA/JAYCOR two layer hydrodynamic primitive equation ocean circulation

model of the Gulf of Mexico on a 0.2 degree grid. Particular attention was given to

specifying the coastline and bottom topography for maximum realism. Model parameters

included: upper layer inflow transport, lower layer inflow transport, wind stress, horizontal

eddy viscosity, grid spacing, upper layer reference thickness, lower layer reference

thickness, minimum depth of bottom topography, Coriolis parameter, gravitational

acceleration, reduced gravity, interfacial stress, coefficient of quadratic bottom stress, and

time step. Experiments were conducted by adjusting these parameters to achieve best

simulations when compared with existing data.

SIGNIFICANT CONCLUSIONS: Changes to the original model parameters such as inflow

transport of the upper and lower layers improved the simulations. The experiment yielding

the best results included the addition of wind forcing after port forcing had fully spun up.

The use of seasonal climatological winds introduced considerable variability and was not a

successful experiment. This experiment also revealed that ocean circulation climatologies

were inappropriate for use in oil spill risk analyses in the Gulf of Mexico.

STUDY RESULTS: Five experiments (Experiments 9, 34, 40, 60, and 68) were included in

the Year 1 report. Experiment 9 gave the best simulation of the Gulf of Mexico at the

beginning of the project, based on available comparative data. The model was driven from

rest to statistical equilibrium solely by a steady inflow through the Yucatan Straits. The

model effectively simulated eddy shedding by the Loop Current. As shed eddies propagate

westward, the model spontaneously develops a counter-rotating vortex pair, a structure

Physical Oceanography 37
observed in the western Gulf of Mexico. The simulation sheds an eddy once every 390

days, and observed eddy shedding cycles were very similar. The eddies generated in

Experiment 9 were large with high maximum currents. In the two layer model, upper layer

transport can be reduced to produce smaller eddies. The use of wind forcing based on

seasonal climatology was used in Experiment 34. Basic circulation patterns exhibited much

more variability in this case. Experiment 40 employed 20 Sverdrup (Sv) upper layer

transport and 10 Sv lower layer transport, as opposed to 26 Sv (upper) and 4 Sv (lower)

used in Experiment 9. This experiment produced sea surface variability maps that were

consistent with maps produced from hydrographic and satellite altimeter data. Experiment

40 was considered the best mean sea surface variability model for the Gulf of Mexico.

Experiment 60 was identical to Experiment 40, except that horizontal eddy viscosity was

reduced. Some new circulation features not seen in Experiment 40 were revealed.

Experiment 68 was identical to Experiment 40 except for the addition of wind forcing after

the port-forced circulation had fully spun up. This experiment produced the furthest

northward penetration of the Loop Current ever attained by simulation. Similar intrusions

have been seen in the Gulf of Mexico. The model's inadequate representation of shelf

topography makes it likely that the currents simulated in shallow water (<1 00 m) were too

high. Simulated surface currents from Experiment 68 were considered the best simulation

data available at the end of Year 1. They consist of velocity component (u and v) fields on

a 0.2 degree rectangular grid covering the Gulf area, sampled every three days for 3,780

model days (10.3 years).

STUDY PRODUCT(S): Wallcraft, A. J. 1984. Gulf of Mexico Circulation Modeling Study

Annual Progress Report, Year 1. A final report by JAYCOR for the U.S. Department of the

Interior, Minerals Management Service Gulf of Mexico OCS Region, Metairie, LA. NTIS No.

PB87-128641. MMS Report 85-0025. Contract No. 14-12-0001-30073. 106 pp.

STUDY TITLE: Gulf of Mexico Circulation Modeling Study.

COMPLETION DATE OF REPORT: November 1984.

CUMULATIVE PROJECT COST: $78,663.

KEY WORDS: Straits of Florida; Eastern Gulf; Central Gulf; Western Gulf; physical

oceanography; currents; modeling; transport; patterns; Loop Current; wind forcing;

seasonality; eddy.

38 Physical Oceanography
kOtTtI C O 110 IDO LIATUTE 0 - - - TOOPIC OF CANCEO GULF OF MEXICO REGION Base map of the entire Gulf of Mexico area.EASTERN
REPORT TITLE: Gulf of Mexico Circulation Modeling Study Annual Progress Report,

Year 2.

MMS PUBLICATION NUMBER: MMS 86-0027.

APPLICABLE PLANNING AREA(S): Straits of Florida; Eastern Gulf of Mexico; Central Gulf

of Mexico; Western Gulf of Mexico.

BACKGROUND: In 1983, the U.S. Department of the Interior funded a four-year

circulation modeling program for the Gulf of Mexico. The first study year tested the two

layer hydrodynamic primitive equation ocean circulation on a 0.2 degree grid. Important

aspects of the first year were correctly specifying coastline and bottom topography for

maximum circulation simulation, and how best to include wind forcing. During the second

study year, investigators utilized the same basic model with various parameter changes to

conduct experiments.

OBJECTIVES: (1) To progressively upgrade in modest increments an existing numerical

ocean circulation model of the Gulf of Mexico so that the final model has horizontal

resolution of about 10 km and vertical resolution approaching 1 to 10 m in the mixed layer,

10 m at the thermocline, and 100 m in deep water.

DESCRIPTION: During this four-year project, the validity of the upgraded model will be

continuously tested, and velocity field time series delivered periodically based on the most

realistic simulation of Gulf circulation available. Experiments during the second year were

with the existing NORDA/JAYCOR two layer hydrodynamic primitive equation ocean

circulation model of the Gulf of Mexico on a 0.1 degree grid. Simulations generated

included wind-forced only, port-forced only, and wind-forced plus port-forced. Model

parameters included: upper layer inflow transport, lower layer inflow transport, wind stress,

horizontal eddy viscosity, grid spacing, upper layer reference thickness, lower layer

reference thickness, minimum depth of bottom topography, Coriolis parameter, gravitational

acceleration, reduced gravity, interfacial stress, coefficient of quadratic bottom stress, and

time step. Experiments were conducted by adjusting these parameters to achieve best

simulations when compared with existing data.

SIGNIFICANT CONCLUSIONS: Simulations using wind forcing only did not provide realistic

Gulf wide circulation patterns. This is because wind-induced flows in the eastern Gulf of

Mexico, except on the continental shelf, are very small relative to the dominant port-forced

Loop Current system. In the western Gulf of Mexico, wind-forced currents were quite

significant. Port-forced experiments provided realistic Gulf wide circulation patterns;

however, there was little variability from one Loop Current eddy cycle to the next. The

port-forced plus wind-forced experiment provided the best simulation of Gulf surface

currents during this study.

STUDY RESULTS: Two wind sets were used in the wind-forcing experiment (seasonal ship

winds and monthly modeled geostrophic winds). Both gave similar results everywhere

except in the southwestern Gulf in winter and spring. The ship observation-based wind

fields generally tended to overestimate wind strengths. Interannual wind variability had

significant effects on the simulation. The port-forcing experiment produced the best

Physical Oceanography 41
simulation and had a horizontal eddy viscosity (A) of 50 m2 sec1 and a coefficient of

quadratic bottom friction of 0.0003. Surface currents were sampled every three days for

complete eddy shedding cycles. Little variability was generated in terms of eddy movement

as all simulated eddies followed the same south of west path across the Gulf. It was

believed that this was the preferred path of actual Loop Current eddies in the Gulf of

Mexico. Generally, the port-forced simulations provide good models of a typical Loop

Current eddy cycle.

Port-forcing plus wind-forcing experiments were difficult to obtain long-term simulations

from because of the effect of wind forcing on the range of horizontal eddy viscosities.

Wind forcing produced upwellings between anticyclonic eddies and the coastline; these

upwellings stopped the simulation. Monthly averaged winds were added after six years of

port-forced spin up. Simulated surface currents were sampled every three days for more

than ten years using this experiment.

STUDY PRODUCT(S): Wallcraft, A. J. 1 986. Gulf of Mexico Circulation Modeling Study

Annual Progress Report, Year 2. A final report by JAYCOR for the U.S. Department of the

Interior, Minerals Management Service Gulf of Mexico OCS Region, Metairie, LA. NTIS No.

PB87-107421. MMS Report 86-0027. Contract No. 14-12-0001-30073. 94 pp.

STUDY TITLE: Gulf of Mexico Circulation Modeling Study.

COMPLETION DATE OF REPORT: April 1986.

CUMULATIVE PROJECT COST: $158,935.

KEY WORDS: Straits of Florida; Eastern Gulf; Central Gulf; Western Gulf; physical

oceanography; currents; modeling; transport; patterns; Loop Current; wind forcing;

seasonality; eddy.

42 Physical Oceanography
GULF OF MEXICO REGION sotwTcLcao io, ------ TOIC OrCANCE 

II Lont. a so oo ISO aoo Base map of the entife Gulf of Mexico area.
REPORT TITLE: Compilation and Summation of Historical and Existing Physical

Oceanographic Data from the Eastern Gulf of Mexico.

MMS PUBLICATION NUMBER: Contract No. 08550-CT4-16.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico.

BACKGROUND: A consortium of oceanographers were contracted by the Bureau of Land

Management to summarize available information concerning the physical oceanography of

the Mississippi-Alabama-Florida (MAFLA) shelf region. The resulting synthesis was to guide

future biological, chemical, geological, and physical oceanographic studies targeted for the

MAFLA region prior to oil and gas exploration activities.

OBJECTIVES: (1) To assemble the historical and contemporary physical and associated

meteorological data of the northeastern Gulf of Mexico for submission to the National

Oceanographic Data Center (NODC); (2) to construct a zero-order synthesis of

oceanographic conditions in the northeastern Gulf and have them graphically displayed; (3)

to describe the general circulation and oceanographic conditions of the northeastern Gulf

continental shelf and in the Loop Current of the deeper Gulf areas; (4) to describe

qualitatively the interaction between the shelf circulation of the northeastern Gulf and the

Loop Current; (5) to describe the seasonal distribution of the fish spawning intensity and

zooplankton productivity on the West Florida Shelf and relate these to temperature and

salinity data; (6) to develop a first-order understanding of the trajectory of a pollutant in the

northeastern Gulf; and (7) to provide recommendations on sampling locations for future

biological, chemical, geological, and physical oceanographic investigations.

DESCRIPTION: Data assembled and synthesized for this report relied on archived and

recently entered hydrographic data (e.g., salinity, temperature, depth) from NODC files.

This information was obtained with expendable bathythermographs, mechanical

bathythermographs, salinity-temperature-depth hydrocasts, current meters, and cyclesonde

meters. Data sets were generated from the general region bounded by 21 to 30°N Lat and

81 to 90°W Long. NODC established a separate file for MAFLA data. At the request of

individual investigators, analyses and graphic displays were produced. Climatic information

was provided by the National Climatic Center.

From 1972 to 1974, ichthyoplankton and zooplankton were sampled with paired 60-cm

Bongo net plankton samplers. Stations were spaced 24 or 48 km apart on a grid from Dry

Tortugas to Cape San BIas and from the 10- to 200-m isobaths at the shelf edge.

SIGNIFICANT CONCLUSIONS: Primary motion inducing forces on the West Florida Shelf

were atmospheric disturbances and the Loop Current. Summer or winter tradewinds

coupled with tropical cyclones, cold fronts, warm fronts, and hurricanes induce

compensatory mass water movements. Primary Loop Current effects include: momentum

and water mass transfer from the Loop Current to the shelf; direct incursions of the Loop

Current onto the shelf; incursions of Loop Current related eddies, and their associated

eddies, onto the shelf; and fluxes of mass from the shelf to the deep basin instigated by

Loop Current features.

Physical Oceanography 45
Three control volumes should be considered for an appropriate sampling grid from which to

gather data to be used in forecasting, monitoring, and numerical modeling: the immediate

vicinity of a drilling unit, the continental shelf from the Mississippi Delta to the Florida Keys,

and the deep basin waters of the eastern Gulf of Mexico. For the first two control volumes,

transheif spacing of current meter moorings should be 25 km. and alongshelf spacing of

moorings should be 100 km. A surface current meter should be attached directly to the

drilling unit. For the shelf volume, additional meters should be deployed at the shelf break.

Monitoring for the deep basin should employ satellite altimeter, satellite imagery, satellite

film loops, moored buoys with thermistor chains, tide gauges, and hydrographic sections.

Process-oriented studies for the shelf should include surface and bottom mixed layer

dynamics during strong meteorological events, surface gravity wave dynamics during strong

meteorological events, dispersal of surface and subsurface materials, and bottom sediment

transport dynamics. Suggested deep basin studies were mainly of Loop Current dynamics.

Particular areas that might receive attention included De Soto Canyon, Cape San Bias, and

the shelf break.

STUDY RESULTS: Meteorologically, there are two distinct seasons in the eastern Gulf of

Mexico: winter and summer. Primary atmospheric disturbances during winter months are

cold fronts, warm fronts, stationary fronts, and occluded fronts. Cold fronts, most

prevalent during winter, move southeast at an average speed of 1 5 to 20 kn and affect

shelf circulation during their passage. Summer atmospheric conditions are primarily affected

by the Bermuda-Azores high pressure ridge; however, tropical waves and tropical cyclones

also occur that exert pronounced effects on hydrographic conditions. Cumulative river

runoff, another hydrographic feature in the MAFLA area, was 18,784 m3 s or 60 x

1010 m3 yr1. The Mississippi River contributes 72% of the total discharge to the MAFLA

area. Tidal and inertial motions produce particle orbits with a radius on the order of several

kilometers and an orbital period on the order of 12 to 28 h. Such particle motions are likely

to play a significant role in horizontal dispersion. Two water masses, the Subtropical

Underwater and the Antarctic Intermediate Water, were traversed by the Loop Current in

deep basin waters of the eastern Gulf of Mexico. Water mass properties, salinity,

temperature, and dissolved oxygen increased in variability with distance from the core of

this current. Based on available data, an annual cycle of the Loop Current was proposed. A

spring intrusion of the Loop Current was followed by maximum penetration in summer. An

anticyclonic eddy then separates from the main flow. During fall, the Loop recedes and

with minimum intrusion occurs during winter. Temporal variability of this cycle was

unknown, but was believed to be substantial. Detached eddies and the Loop Current often

flow directly onto the shelf, usually during summer, and considerably influence shelf

circulation. Mean current flow on the shelf usually parallels local depth contours, although

near-surface currents on the outer shelf often flow perpendicular to depth contours. This

indicates the presence of surface currents and undercurrents operating within the system.

Low frequency components, with periods of 5 to 20 days, are important contributors to

shelf circulation patterns. Low frequency components were 50 cm s as opposed to

10 cm s for tidally induced flows. On a time scale of several days to a week, the

advective flow field is dominated by low frequency fluctuations. Thermal stratification on

the shelf intensified in a shoreward direction during summer. In winter, shelf waters were

well mixed vertically, mainly due to atmospheric (wind) forcing. A 25-rn thermocline

advances shore from January-February to May-June, and moves seaward in August.

46 Physical Oceanography
Lowest average surface salinities (21 ppt) of shelf waters were recorded during March, and

lowest bottom salinities never dropped below 30 ppt at any time. Seasonal cycles in

surface salinities were associated with riverine discharges.

Many of these circulation characteristics were responsible for the observed distribution of

zooplankton and ichthyoplanktori. Mean zooplankton volumes ranged from 69.1 to

287.8 ml 1,000 m3. Mean fish egg abundances ranged from 163.1 to 927.1 under 10 m2

of sea surface. Mean larval fish abundances were 55.3 to 825.4 under 10 m2 of sea

surface. Zooplankton, fish eggs, and fish larvae had standing crop values that peaked

during summer and dropped during winter. Generally, zooplankton and ichthyoplankton

were concentrated in the northern half of the study area, but pooled means did not differ

greatly between sectors. Seasonal abundance patterns of fish eggs and larvae were more

pronounced within the 50-m isobath. In general, correlations among biological variables

(concentrations of organisms) and other environmental variables (temperature and salinity)

were not apparent. A biological phenomenon known as red tide is dependent on circulation

pattern and is due to massive blooms of the dinoflagellate Gymnodinium breve. The actual

triggering mechanisms for these blooms is unknown, but ambient currents are important in

transporting the red tide and determining subsequent effects.

STUDY PRODUCT(S): State University System of Florida, Institute of Oceanography.

1975. Compilation and Summation of Historical and Existing Physical Oceanographic Data

from the Eastern Gulf of Mexico. A report for the U.S. Department of the Interior, Bureau

of Land Management Gulf of Mexico OCS Office, New Orleans, LA. NTIS

No. PB8O-1 901 68. Contract No. 08550-CT4-16. 97 pp. + app.

STUDY TITLE: MAFLA OCS Hydrographic Study.

COMPLETION DATE OF REPORT: July 1975.

CUMULATIVE PROJECT COST: $174,040.

KEY WORDS: Eastern Gulf; Central Gulf; Mississippi; Alabama; Florida; baseline; physical

oceanography; hydrography; Loop Current; fish; spawning; meteorology; seasonality.

Physical Oceanography 47
LOUISIANA MORGAN CITY MISS. ' I: ,,.\,: PENSACOLA S4 

STUDY AREA FOR THE COMPILATION AND SUMMATION OF HISTORICAL AND EXISTING PHYSICAL OCEANOGRAPHIC DATA FROM THE GULF OF MEXICO.
MARINE ECOSYSTEMS

The Marine Ecosystem Studies Series includes major field efforts addressing

multidisciplinary data gathering, analysis, and interpretation. The objectives of these

studies were to gather data characterizing the physical environment and biological

communities prior to the onset of oil and gas activities in so-called "frontier" areas, so

that changes in these characteristics following oil and gas exploration and development

could be ascertained and perhaps mitigated. The baseline studies were brought to an

abrupt halt in late 1 978 following criticism by various individuals and agencies that the

studies did not provide information in a timely manner for lease-management decisions.

That is, information describing the physical environment, biological habitats and

communities, and naturally occurring regional hazards is needed to make management

decisions regarding advisability of leasing in particular areas. Information is also

needed for stipulations to mitigate both the hazards to the offshore operations and the

hazards to the environment caused by the offshore operations. Similarly, information is

needed to define the terms of the lease stipulations or other mitigating measures to

assure their effectiveness.

Marine Ecosystems 49
REPORT TITLE: The Ecological Communities of the Continental Slope and Adjacent

Regimes of the Northern Gulf of Mexico.

MMS PUBLICATION NUMBER: Contract No. AA851-CT1-12.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico;

Western Gulf of Mexico.

BACKGROUND: This report dealing with the deepwater ecological communities of the Gulf

of Mexico was based upon collection of the macroinfauna and megaepifauna made from

1964 to 1973 aboard Texas A&M University's (TAMU) ship the R/V ALAMINOS. The

research was sponsored by various organizations including TAMU, the Office of Naval

Research, the National Science Foundation, the Atomic Energy Commission, the Bureau of

Land Management, and others.

OBJECTIVES: (1) To describe and discuss the ecological nature and distribution of the

macroepibenthic assemblages that occur in the northern Gulf of Mexico; (2) to provide

photographic documentation of the nature of the benthic environment within which these

assemblages exist, including portrayal of some constituent species that exist within

bathymetric zones; (3) to describe, after analyzing available data generated by the present

study and found in extant literature, the important gaps in the knowledge of the area, its

assemblages, and functioning of the deep ecosystem and then suggest study approaches to

reduce these gaps; and (4) to provide an assessment of the significance of the potential

impacts on the deep macrobenthic communities by oil and gas exploration and production.

DESCRIPTION: Macro- and megaepifauna were collected using five types of dredges

including a Menzies dredge, a plow dredge, a scoop dredge, a 3-rn gape skimmer dredge,

and a 2-rn gape skimmer dredge. A 20-rn otter trawl net was also used. A Campbell grab

collecting 0.62 m2 surface area and a Phleger corer were used to collect the macroinfauna

and sediment samples, respectively. Two different cameras were used to collect

photographic data: a 35-mm underwater multi-exposure model (Alpine Geophysical

Associates, Model 314) and a 70-mm Shipek Deep-Sea Camera (Hydro Products Model

PC-700). Both cameras were equipped with a 200 watt-second strobe and were focused at

approximately 1 .5 m. The study area extended from 25°N lat northward to approximately

the 1 50-m isobath and from the east wall of the DeSoto Canyon and the easternmost

extension of the Mississippi Fan to the Sigsbee Abyssal Plain and up the slope to the shelf

break south of Brownsville, Texas. A total of 1 93 stations were sampled in water depths of

81 to 3,801 m from 1964 to 1973. Specimens were sorted and preserved in formalin in the

field, transferred to laboratories at TAMU, and then sent to taxonomic specialists for

identifications. Clustering, applied to faunal similarity indices for each 50-rn depth interval,

was used to construct a dendrogram to delineate faunal breaks across the slope, rise, and

abyssal plain.

SIGNIFICANT CONCLUSIONS: Relative abundances and distributions of various groups of

macroepifauna including echinoderms, crustaceans, fishes, gastropods, cephalopods,

sponges, coelenterates, bryozoans, brachiopods, and sipunculids, and infauna consisting of

polychaetes, bivalves, and scaphopods were discussed. Five faunal zones were recognized

to occur from the shelf to the abyss in the northern Gulf of Mexico, conforming reasonably

Marine Ecosystems 51
well with zones described for the northwest Atlantic Ocean. The DeSoto Canyon,

Mississippi Trough, and Alaminos Canyon were three canyon systems recommended for

future studies.

STUDY RESULTS: The Shelf/Slope Transition Zone assemblage (150 to 450 m) was

dominated by demersal fishes, asteroids, and brachyurans with gastropod molluscs and

polychaetes also well represented. The Archibenthal Zone assemblage (475 to 950 m) was

dominated by demersal fishes, asteroids, and gastropod molluscs with holothuroids

increasing in number and brachyurans declining drastically. The Upper Abyssal Zone

assemblage (975 to 2,250 m) showed a continuing decrease in demersal fishes and

brachyurans, a major increase in the number of species of large holothuroids, and a peak in

the number of sponge and gastropod species. The Mesoabyssal Zone (2,275 to 3,200 m)

was characterized by large declines in all major species groups. The Lower Abyssal Zone

assemblage (3,225 to 3,850 m) had the lowest species richness of all the zones but also

possessed a benthic species assemblage not occurring elsewhere in the Gulf. Key species

from each of these zones were determined based upon frequency of appearance in samples

and numbers collected per trawl.

A deep ecosystem model was proposed consisting of three distinct layers: the euphotic zone

extending from the surface to a depth of about 60 m, the aphotic zone extending from the

euphotic zone to within a meter of the bottom, and the seafloor with an approximately 1-m

thick contiguous water layer. Each of these three functionally distinct layers was further

broken down into a five-reservoir food chain. Sources of matter and energy for the

ecosystem come not only from the primary productivity of the phytoplankton being passed

down the food chain but also from dissolved organic matter, deadfalls of animal carcasses,

fallout of terrestrial and shallow marine plants, transport of animals and organically rich

sediments in slumps and turbidity flows, and active foraging of demersal fishes and large

benthic crustaceans in the midwater region.

Various potential hazards to the deep Gulf ecosystem were discussed and included various

types of chemical pollution including oil spills, increased terrestrial sediment deposition, and

bottom sediment slumping. Guidelines were proposed for avoiding significant impacts upon

the ecosystem by petroleum activities. Major information deficiencies of the deep Gulf of

Mexico were also summarized and included measurements of the organic content of the

sediments and water column, dissolved oxygen levels within 1 m of the bottom and Eh

values in adjacent sediments, the residence time of waters in the Gulf, levels of dissolved

metals and various organic pollutants in sediment pore water, information on currents

occurring on the continental slope and abyssal plain, the effects of slumping and turbidity

flows on the fauna, studies on the deepwater microbiology, comparisons of meiofaunal and

macrofaunal abundances from the same areas, and studies of benthopelagic organisms

which are capable of transferring major amounts of organic matter between the pelagic and

benthic environments.

STUDY PRODUCT(S): Pequegnat, W. E. 1983. The Ecological Communities of the

Continental Slope and Adjacent Regimes of the Northern Gulf of Mexico. A final report by

TerEco Corporation for the U.S. Department of the Interior, Minerals Management Service

Gulf of Mexico OCS Office, Metairie, LA. Vol. I - NTIS No. PB84-1 13406; Vol. II - NTIS No.

PB84-113398. Contract No. AA851-CT1-12. 715 pp.

52 Marine Ecosystems
The report also contained three appendices: Appendix A, consisting of an atlas of bottom

photographs depicting some of the biological components, physiography, and surficial

sediments of the five described faunal zones; Appendix B, containing a listing of collected

species; and Appendix C, presenting an annotated bibliography of publications dealing with

the oceanography of the Gulf of Mexico.

STUDY TITLE: Ecological Communities of OCS Slope and Adjacent Regimes of Northern

Gulf of Mexico.

COMPLETION DATE OF REPORT: August 1983.

CUMULATIVE PROJECT COST: $213,319.

KEY WORDS: Eastern Gulf; Central Gulf; Western Gulf; DeSoto Canyon; Sigsbee Abyssal

Plain; biology; benthos; epifauna; infauna; benthic photographs; sediment; slope; rise;

abyssal plain; abundance; distribution; fish; faunal zones; modeling; maps; bibliography;

community.

Marine Ecosystems 53
GALVESTON NEW ORLEANSOULFPORT P ENS AC O(.A PANAMA crry TA

2 WESTERN -. CENTRAL GULF OF MEXICO REGION STATUT( I(.($ 0 -._ TROPIC OF CANCER - - 

EASTERN RIL0MrT(S 0 00 00 00 000 GEOGRAPHIC LOCATIONS OF BENTHIC STATIONS SAMPLED BY THE R/V ALAMINOS AND DESCRIBED IN THE ECOLOGICAL CO

OCS SLOPE AND ADJACENT REGIMES OF NORTHERN GULF OF MEXICO.,
REPORT TITLE: Northern Gulf of Mexico Topographic Features Study. Vols. I through VI.

MMS PUBLICATION NUMBER: Contract No. AA551-CT8-35.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico;

Western Gulf of Mexico.

BACKGROUND: The geology and biology of 28 banks in the northwestern Gulf of Mexico

were characterized by studies that began in 1974. This study concerned eight additional

banks (i.e., Alderdice, Coffee Lump, Diaphus, Elvers, Fishnet, Geyer, Jakkula, and

Rezak-Sidner) and provided additional information on four banks previously studied [i.e.,

Applebaum (previously called Little Sister), 32 Fathom, and East and West Flower Garden

Banks]. Florida Middle Ground, a unique biotope off Floridas western coast, was also

included in this investigation.

OBJECTIVES: (1) To gather biological, chemical, geological, geophysical, and physical

oceanographic data to characterize selected topographic features and the Florida Middle

Ground; (2) to perform descriptive reconnaissance studies to assess the biology and geology

of the features; (3) to conduct chemical analyses for trace metals, high molecular weight

hydrocarbons (HMWHC), Delta 13C and total organic carbon in Coffee Lump and East and

West Flower Garden Banks sediments; (4) to analyze Spondylus and certain fish species

collected at the Flower Garden Banks for trace metals and HMWHC, and to analyze water

samples for nutrients and dissolved oxygen; (5) to study the size distribution and mineralogy

of sediments at select banks; (6) to continue study of reworked fossil coccolith

distributions; (7) to continue the East Flower Garden Bank coral, coralline algae,

zooplankton, algae, and brine seep monitoring study; and (8) to perform mapping,

hydrocarbon analysis, and monitoring studies at West Flower Garden Bank.

DESCRIPTION: Approximately 2,110 statute miles of survey data from eight northern Gulf

of Mexico banks and the Florida Middle Ground were obtained during the first mapping

cruise. The second mapping cruise was limited to West Flower Garden Bank. Two

submersible cruises were conducted for biological and geological reconnaissance and

sampling to characterize biotic communities and surficial geology; the submersible was

equipped with a manipulator arm, a wire mesh collection basket, and a scoop sediment

sampler. For dives at the brine pool, a temperature probe and vacuum collection hose were

added to the arm for collection of in situ data and water samples. Data collection

associated with sedimentary processes in the bottom boundary layer at East Flower Garden

Bank was accomplished through attachment of a transmissometer, salinity/temperature!

depth (STD) system, and profiling current meter to the submersible. The coral and coralline

algal population phase of the East Flower Garden Bank monitoring study included dive teams

that photographed random 1 0-rn line transects; photographic mosaics were used in species

identification and transect analyses. The study of recruitment and early growth of corals

and coralline algae was conducted using a stereo dissecting microscope and counting grid.

Coelenterate larvae and other zooplankton were collected with 0.333-mm mesh nets fitted

on a buoy array; nets fished at depths measured in 10-m increments from the surface to

40 m for 1 h of sampling. Water column measurements were taken with a

transmissometer, Niskin bottles, STD system, and profiling current meter. For long-term

current measurements, current meter arrays were set near East and West Flower Garden

Marine Ecosystems 55
Banks. All Spondylus samples for trace metal and HMWHC analyses were collected by the

submersible. Sediments for similar analyses, Delta 13C, fossil coccoliths, and total organic

carbon were taken with a Smith-Mcintyre grab.

SIGNIFICANT CONCLUSIONS: Significant correlation was found between biotic zonation,

substrate nature, and top depth of the nepheloid layer. There was no indication of

significant change in benthic community condition at East Flower Garden Bank. Biological

zonations at West Flower Garden, Alderdice, Elvers, Geyer, Jakkula, and Rezak-Sidner Banks

were similar to those at East Flower Garden Bank and therefore warrant a protective

classification. The Florida Middle Ground was of particular concern because of its unique

fragile biota.

STUDY RESULTS: Crests of Alderdice, Elvers, Geyer, Jakkula, and Rezak-Sidner Banks

were above the normal depth of the nepheloid layer and had reef-building populations of

coralline algae within well developed Algal-Sponge Zones. These banks also displayed

normal carbonate sands associated with biogenic reefs. Diaphus Bank might also have an

Algal-Sponge Zone, but its crest was near the lower depth limit of this zone at the Flower

Garden Banks. Applebaum, Coffee Lump, Fishnet, and 32 Fathom Banks had less diverse

benthic assemblages adapted to chronic turbid water conditions. Strong correlation was

found between biotic zonation, substrate nature, and top depth of the nepheloid layer.

Currents at the Flower Garden Banks were steered by topography. Water from the base of

East Flower Garden Bank cannot flow up to the level of the living reef. Silt and clay were

nearly absent from the bank above 80 m, an approximate depth of biotic change; a

clear-water fauna existed above that depth but was missing below it.

The crestal graben typical of most banks investigated has not developed at East Flower

Garden Bank; significant normal faulting has not yet occurred. A crestal graben has

developed at West Flower Garden Bank; continued movement along the faults is expected.

Applebaum, Coffee Lump, and 32 Fathom Banks were similar in structure and sediments

and considered relatively inactive banks underlain by salt diapirs that have not moved

appreciably upward since late Pleistocene times. The remaining banks were described as

tectonically active with geologically recent faulting common in their immediate vicinity. No

significant changes in benthic community structure or condition at East Flower Garden Bank

were noted. There were no changes in rate of accretionary growth of dominant corals over

the last decade. Rates of encrusting coral growth and coral mortality were highly variable;

there was no indication that encrusting growth had been impaired or that mortality had

increased. Larval coral settlement, early growth, and development occurred at normal

rates. Leafy algal populations appeared normal and were largest in spring. There was no

obvious change in health of benthic communities southeast of the main coral reef at East

Flower Garden Bank. The condition of corals and coralline algae within the Algal-Sponge

Zone appeared similar to that of previous years. There were no signs of mass mortalities for

any conspicuous community component. Natural brine seep effects on benthic biota at East

Flower Garden Bank were restricted to an area within a few meters of the seep and

recognizable brine-seawater mixture. West Flower Garden Bank had biological zonation

similar to that of East Flower Garden Bank (i.e., classified as a sensitive environment).

Other banks classified as sensitive included Alderdice, Elvers, Geyer, Jakkula, and

Rezak-Sidner Banks. The presence of larger areas of clear-water reefal communities in the

upper portion of these banks warrants protection. Remaining banks were classified as being

56 Marine Ecosystems
of low priority. Overall, diversity and abundance of benthic biota were low compared to

those of other shelf-edge banks in the northwestern Gulf. Applebaum, Coffee Lump, and

32 Fathom Banks were compared to south Texas fishing banks with respect to the

hard-bottom assemblage (Antipatharian Zone) of organisms. Low diversity and abundance

of berithic biota on Diaphus and Fishnet Banks were attributed to chronic turbidity and

sedimentation. Nevertheless, snapper and other game fishes were numerous in the vicinity

of these banks. Mapping, geological sampling, and physical and chemical studies

established a background for biological studies at the Florida Middle Ground. A unique

biotope and a habitat of particular concern because of the extremely fragile biota, it

supports both a Caribbean eurythermal species complex and a Caribbean restricted species

complex of algae, invertebrates, and fishes. This study explored the possibility of using

selected cryptofaunal hosts as quantitative sampling units, and elucidated which faunal

groups would yield the most useful results. It was speculated that during extremely cold

winters, a combination of storm surge and cold water (12 to 13°C) remaining in the area for

several days could bring about depauperation of the more tropical species that inhabit the

Florida Middle Ground.

STUDY PRODUCT(S): Rezak, R. and T. J. Bright. 1981. Northern Gulf of Mexico

Topographic Features Study. A final report by Texas A&M University Department of

Oceanography for the U.S. Department of the Interior, Bureau of Land Management Gulf of

Mexico OCS Office, New Orleans, LA. Vol. I (Introduction, Geology, Biotic Zones and

Banks, Water and Sediment Dynamics, Summary and Recommendations) - NTIS No.

PB81-248650 (PC/A07); Vol. II (Methods, Sediment Dispersal, Chemical Analyses) - NTIS

No. PB81-248668 (PC/A08); Vol. III (Flower Garden Banks) - NTIS No. PB81-248676

(PC/A09); Vol. IV (Coffee Lump Bank, Fishnet Bank, Diaphus Bank, Jakkula Bank, Elvers

Bank, Rezak-Sidner Bank, Alderdice Bank, 32 Fathom Bank, Applebaum Bank) - NTIS No.

PB81-248684 (PC/A09); Vol. V (Florida Middle Ground) - NTIS No. PB81-248692 (PC/Al 2);

Vol. VI (Executive Summary) - NTIS No. PB81-248643 (PC/A07); Set (6 Vol.) - NTIS No.

PB81-248635 (PC/E99). Contract No. AA551-CT8-35. Tech. Rept. No. 81-2-T.

STUDY TITLE: Gulf of Mexico Topographic Features Study.

COMPLETION DATE OF REPORT: March 1981.

CUMULATIVE PROJECT COST: $2,891,344.

KEY WORDS: Eastern Gulf; Central Gulf; Western Gulf; Alderdice Bank; Coffee Lump

Bank; Diaphus Bank; Elvers Bank; Fishnet Bank; Geyer Bank; Jakkula Bank; Rezak-Sidner

Bank; Applebaum Bank; 32 Fathom Bank; East Flower Garden Banks; West Flower Garden

Banks; geology; biology; hydrography; Florida Middle Ground; maps; bathymetry;

submersible; trace metals; hydrocarbons; sediment; water column; nutrients; fish;

monitoring; nepheloid layer; tissue.

Marine Ecosystems 57
KEY MAP! LOUISI AN A MOPSAN CITY . FISHNET COFFEE LUMP 32 FATHOM S DIAPHUS S ALDERDICE APPLEBAUM I3EYER ELVERS REZAKSIDNER JAKXULA . MISSISSIPPI MOSILE WEST FLOWER GARDEN EAST FLOWER GARDEN OULP OP MIXICO NtOION - 0 / 0 25 50 15 00 KILOMET

I I APPROXIMATE LOCATIONS OF BANKS INVESTIGATED DURING THE NORTHERN GULF OF MEXICO TOPOGRAPHIC FEATURES 

25 50 75 
REPORT TITLE: Annual Report for Northern Gulf of Mexico Continental Slope Study.

MMS PUBLICATION NUMBER: MMS 85-0058.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico;

Western Gulf of Mexico.

STUDY TITLE: Northern Gulf of Mexico Continental Slope Study.

BACKGROUND: Little information is available concerning the biology, geology, and

chemistry of continental slope environments in the Gulf of Mexico. With the growing

potential of oil and gas exploration on the slope, additional environmental data will be

required by resource managers faced with leasing decisions. The U.S. Department of the

Interior has sought to further the understanding of slope habitats by funding a four-year

investigation of the continental slope environments of the northern Gulf of Mexico.

OBJECTIVES: (1) To determine the abundance, structure, and distribution of animal

communities in the deep sea in the Gulf of Mexico; (2) to determine the hydrographic

structure of the water column and bottom conditions; (3) to determine and compare

sedimentary characteristics; (4) to relate differences in biological communities to

hydrographic, sedimentary, and geographic variables; (5) to assess seasonal changes in

biologicalcommunities in terms of abundance, structure, animal size, and reproductive

state; and (6) to measure present levels of hydrocarbon contamination in sediments and

selected animals prior to, and in anticipation of, petroleum resource development beyond

the shelf-slope break.

DESCRIPTION: All sampling efforts were confined to the northern Gulf of Mexico, north of

27°N Lat, where physical, chemical, and biological characteristics of the water column and

seafloor were obtained. Three transects were established perpendicular to the slope, each

comprised of five stations. One transect was located in each of the three Gulf of Mexico

Planning Areas (Eastern, Central, and Western). Average sample depths along each transect

were 348, 657, 839, 1,341, and 2,530 m which correspond to previously proposed faunal

zones: Shelf/Slope Transition (150-450 m); Archibenthal, Horizon A (475-750 m);

Archibenthal, Horizon B (775-950 m); Upper Abyssal (975-2,250 m); and Mesoabyssal,

Horizon C (2,275-2,700 m). In November 1983, only the Central Transect was sampled.

During April 1984, all three transects were sampled.

Field sampling consisted of taking water column measurements, sampling bottom sediments

for physical/chemical characteristics and meiofauna and macroinfauna, and collecting and

photographing demersal fishes, epifauna, and macroinvertebrates and their habitats.

Hydrographic measurements included continuous and discrete samples. Discrete sampling

employed a 12-bottle rosette sampler which provided water samples for temperature,

salinity, dissolved oxygen, and particulate organic carbon (POC) determinations. For

sediment sampling, six replicate box cores (24.5 x 24.5 x 44 cm) were taken at each of the

Central Transect stations during both cruises; three replicates were taken at each of the

Eastern and Western transect stations. Undisturbed and uncontaminated sediment samples

for analysis of hydrocarbons, grain size, carbonate, total organic carbon, meiofauna, and

infauna were subsampled from each box core. In the laboratory, sediments were analyzed

Marine Ecosystems 59
for grain size, organic carbon, and carbonate carbon content. Epifauna, macroinvertebrates,

and demersal fishes were collected using a 9-rn, semi-batlon trawl with 3.8 cm stretch mesh

and 1 .3 cm cod end mesh. A single haul was taken at each station. Benthic photography

used a Benthic Underwater Camera System (a Benthos 35 mm camera mounted on a sled

equipped with a pinger operated altimeter). Carbon isotopic analyses were performed on

sediments and selected organisms to determine carbon source. High molecular weight

hydrocarbons in macroepifauna, infauna, fishes, and sediments were determined using total

scanning fluorescence followed by gas chromatography/mass spectroscopy.

SIGNIFICANT CONCLUSIONS: After one sampling year, analyses were incomplete and no

definite conclusions could be reached. Biological and physical parameters exhibited some

spatial and temporal variability among transects. Evidence of anthropogenic hydrocarbon

contamination was not found in the slope environment or biota thus far examined. Natural

hydrocarbon seeps were prevalent in the vicinity of the Central Transect and may, in fact,

provide an additional source of energy to newly discovered chemosynthetic communities in

this region.

STUDY RESULTS: Environmental parameters of the water column follow the layers of Gulf

of Mexico, Tropical Atlantic Central, Antarctic Intermediate, and Gulf Deep Waters. Water

mass characteristics were uniform across the Gulf as observed by temperature, salinity, and

transmissometry profiles. Water temperature decreased with depth, ranging from 10.8°C in

346 m to 4.3°C in 2,567 m. Sediment data from the Central Transect revealed clay sized

particles from the three shallow stations grading into sandy or silty clays at the deepest

stations. The western transect stations graded from sand-silt-clay mixtures to silty clays at

the deeper stations. The Eastern Transect contained mostly sandy clay. Eastern and

Western Transect sediments contained a higher proportion of sand-sized particles than the

Central Transect. Organic carbon levels in bottom sediments were generally higher for the

shoreward stations; highest on the Central Transect at all sampling depths, and lowest on

the Eastern Transect. The Eastern Transect contained the highest calcium carbonate levels

of the three transects. Carbon isotope analyses from Central Transect stations indicated

organic carbon derived from planktonic algae with no trends related to depth or distance

offshore. Sediments in all three transects contained a mixture of thermogenic, terrigerious,

and planktonic hydrocarbons. The influence of riverborne hydrocarbons was greatest at the

Central Transect. Hydrocarbon distributions at the Central Transect were consistent with

mixed biogenic and thermogenic sources. In general, hydrocarbons were only present in low

concentrations, especially at the Eastern Transect. Aliphatic hydrocarbon levels ranged

from 10 to 50 ppm.

Meiofaunal samples consisted mostly of nematodes, harpacticoid copepods, polychaetes,

ostracods, and kinorynchs. AU groups were most abundant on the Central Transect.

Nematodes and harpacticoids were the most abundant groups from a total of 36 groups.

Meiofaunal densities along the Central Transect ranged from 1 .1 39 to 274 organisms

m2. The most abundant macroinfaunal groups were polychaetes and nematodes, followed

by harpacticoids, isopods, bivaLves, ostracods, and tanaidaceans. Most macroinfaunal

densities ranged from 2,435 to 8,628 organisms m2. Macroinfaunal densities from the

Eastern and Central Transects were greater than the Western Transect. Megafaurial

invertebrates collected by trawling included 78 decapod (mostLy galatheids and anomurans)

species and 33 echinoderm species (not including brittle stars). A total of 94 species of

60 Marine Ecosystems
demersal or benthopelagic fishes in 42 families was collected on the three transects.

Species from the families Macrouridae, Rajidae, Ophidiidae, Synaphobranchidae, and

Halosauridae accounted for 38% of the total collected.

Benthic photography was refined and developed during this study phase. Preliminary results

of photographic analysis, conducted at one station of each transect, indicates that the

Central Transect station was characterized by a greater density of both biota and

lebensspuren than the other two stations.

STUDY PRODUCT(S): LGL Ecological Research Associates, Inc. and Texas A&M

University. 1985. Annual Report for Northern Gulf of Mexico Continental Slope Study.

Vol. II, Annual Report. A final report for the U.S. Department of the Interior, Minerals

Management Service Gulf of Mexico OCS Region, Metairie, LA. NTIS No. PB86-246352.

Contract No. 14-12-0001-30046. 290 pp.

LGL Ecological Research Associates, Inc. and Texas A&M University. 1 985. Annual Report

for Northern Gulf of Mexico Continental Slope Study. Vol. I, Executive Summary. A final

report for the U.S. Department of the Interior, Minerals Management Service Gulf of Mexico

OCS Region, Metairie, LA. NTIS No. PB86-246345. MMS Report 85-0058. Contract No.

14-12-0001-30046. 18 pp.

COMPLETION DATE OF REPORT: May 1 985.

CUMULATIVE PROJECT COST: $1,136,128.

KEY WORDS: Eastern Gulf; Central Gulf; Western Gulf; biology; hydrography; physical

oceanography; sediment; seasonality; community; benthos; hydrocarbons; slope; fish;

infauna; epifauna; benthic photographs.

Marine Ecosystems 61
LOUISIANA MOflOAN CITY Is. PANAMA I? 

Cf MT S At. OULP OP MIXICO SIOION LAITIPIM SAMPLING STATIONS FOR THE GULF OF MEXICO CONTINENTAL SLOPE STUDY, YEAR 1. I 5$ SO 

0 55 50 TI 10
REPORT TITLE: Tuscaloosa Trend Regional Data Search and Synthesis Study. Vol. I,

Synthesis Report; Vol. II, Supplemental Report.

MMS PUBLICATION NUMBER: MMS 84-0056.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico.

BACKGROUND: The Tuscaloosa Trend Region, extending from southern Louisiana into

offshore waters of the Chandeleur Islands and eastward to DeSoto Canyon, may prove to be

highly productive in terms of recoverable oil and natural gas reserves. The area supports

significant recreational and commercial fisheries and a portion lies within Breton National

Wildlife Refuge and Gulf Islands National Seashore. Information describing the environment

is needed by the Minerals Management Service to make management decisions regarding

leasing a particular area and to define lease stipulation terms.

OBJECTIVES: (1) To identify and summarize important information pertaining to the

environmental and socioeconomic characteristics of the Tuscaloosa Trend Region of the Gulf

of Mexico.

DESCRIPTION: The Tuscaloosa Trend Region is located in the north-central Gulf of Mexico

adjacent to Louisiana, Mississippi, and Alabama. The boundaries are defined as South Pass

on the west (i.e., southeast corner of the Mississippi River Delta), a line from the DeSoto

Canyon head to the Alabama-Florida boundary on the west, and the 200 m contour

offshore. This report characterizes the area with respect to physiography, geology, physical

oceanography, chemical oceanography, biology, socioeconomics, and an area-wide

conceptual ecosystem model. Conceptual representation of physical, chemical, geological,

and ecological processes were developed for the Tuscaloosa Trend ecosystem as part of the

data search and synthesis effort. These representations were developed to provide a

framework for this effort and to direct future research.

SIGNIFICANT CONCLUSIONS: The conceptual representation of the Tuscaloosa Trend

Region was hierarchical, consisting of three levels: Level 1, the whole ecosystem; Level 2,

individual subsystems (e.g., sedimentological, biogeochemical, and ecological); and Level 3,

specific ecological applications (e.g., nekton life history, marsh-estuarine interactions,

pelagic and benthic food webs). The conceptual model provides a management device

which clearly identifies interrelationships and potential multiple use conflicts among

resources. Significant data gaps exist particularly regarding open shelf geology, physical

and chemical oceanography, ecosystem structure and function, and interrelationships

between open shelf and nearshore ecosystems.

STUDY RESULTS: The coastal portion of the Tuscaloosa Trend Region is separated from

the oceanic portion by islands and passes. Chandeleur and Breton Sounds are shallow (2 m

average depth) areas behind several clusters of islands associated with subsidence of the

now-abandoned St. Bernard Delta complex. Lake Borgne lies north of these features and

forms the west end of Mississippi Sound, a shallow (3 m average depth) area behind six

barrier islands (Cat, West and East Ship, Horn, Petit Bois, and Dauphin). The sound receives

freshwater discharges from the Pearl and Pascagoula Rivers. Shallow (3 m average depth)

Marine Ecosystems 63
Mobile Bay, a submerged river valley, and Bon Secour Bay, behind Ft. Morgan Peninsula,

form the eastern coastal portion.

The oceanic portion lies on the Mississippi-Alabama shelf, a triangular shaped region

between the Mississippi River Delta and DeSoto Canyon. The shelf width varies: 10 km off

the Mississippi Delta, 56 km at DeSoto Canyon, and 1 28 km at the widest part east of the

Delta. The shelf slope break occurs at 55 m average depth.

The primary geologic feature of the Tuscaloosa Trend Region is the Gulf coast geosyncline,

a clastic wedge extending from Alabama to northeastern Mexico. The continental shelf

topography and sediment distribution results from combined sea level transgressiveregressive episodes and deltaic progradation and destruction. The present Mississippi River

deposition seems to be shifting to the Atchafalaya Basin. Little active sedimentation is

occurring in the Trend area, which enables the persistence of the DeSoto Canyon, an

S-shaped canyon formed by late Tertiary erosion, deposition, and structural control by

diapiric activity.

Geological processes in the Trend area include relatively rapid bathymetric changes related

to the delta front depositional patterns as well as long-term geologic structure formation and

movement (e.g., salt domes and faults). Potential Trend area geohazards result from

diapirism, rapid deltaic sediment accumulation, and shelf break wasting.

The Trend area is influenced primarily by the anticyclonic Bermuda High in spring and

summer and by continental pressure systems in fall and winter. Seasonal tropical cyclones

periodically impact the area. Wave heights are primarily wind speed and direction

influenced.

Riverine discharges from the Mississippi, Pearl, Pascagoula, and Mobile Rivers strongly

affect the turbidity levels, temperature, and salinity of the Trend area coastal and shelf

waters. The Loop Current, a dominant Gulf of Mexico circulation feature, has periodic

intrusions into the area. DeSoto Canyon may act as an intrusion conduit. Sustained winds

are the dominant inner continental shelf and coastal water circulation driving force, while

riverine discharges also influence circulation in shallow Mississippi Sound and Mobile Bay.

Semidiurnal tides (average tidal range from 37 cm in the mouth of Mobile Bay, to 47 cm in

Chandeleur Sound) influence currents through the passes.

Chemical oceanography of coastal waters is better known than for outer continental shelf

waters in the Trend area. Levels of dissolved oxygen, nutrients, sediment trace metals,

sediment and water hydrocarbons, suspended particulates, heavy metals, and particulate

organics and carbon demonstrate seasonal and geographical trends. Low heavy metal

concentrations in biota reflect minimal anthropogenic contamination.

Coastal marshes fringing the Trend area seasonally contribute large amounts of organic

material to coastal waters. Net organic material export from the marshes is episodic. The

coastal area has three principal food chains: primary production and consumption of marsh

and seagrass vegetation; detritus production by the marshes and seagrasses for a

detritus-based food chain; and phytoplankton production linked to higher trophic levels by

64 Marine Ecosystems
zooplankton. Coastal area nekton and macroepifauna are relatively well-studied because of

their economic importance.

The open shelf ecosystem has two principal food chains: plankton-based (water column) and

detritus-based (benthic). Open shelf nekton is a mixture of coastal and marine organisms.

Open shelf epifaunal communities are well-described as distinct assemblages.

Trend area socioeconomic resources include waterborne commerce, travel and tourism,

sport and commercial fisheries, and oil and gas.

STUDY PRODUCT(S): Barry A. Vittor & Associates, Inc. 1985. Tuscaloosa Trend

Regional Data Search and Synthesis Study. Vol. I, Synthesis Report. A final report for the

U.S. Department of the Interior, Minerals Management Service Gulf of Mexico OCS Region,

Metairie, LA. NTIS No. PB86-245941. MMS Report 84-0056. Contract No.

14-12-0001-30048. 503 pp.

Barry A. Vittor & Associates, Inc. 1985. Tuscaloosa Trend Regional Data Search and

Synthesis Study. Vol. II, Supplemental Report. A final report for the U.S. Department of

the Interior, Minerals Management Service Gulf of Mexico OCS Region, Metairie, LA. NTIS

No. PB86-245958. MMS Report 84-0057. Contract No. 14-12-0001-30048. 374 pp.

STUDY TITLE: Tuscaloosa Trend Regional Data Search and Synthesis.

COMPLETION DATE OF REPORT: June 1985.

CUMULATIVE PROJECT COST: $285,475.

KEY WORDS: Eastern Gulf; Central Gulf; Louisiana; Mississippi; Alabama; Tuscaloosa

Trend; biology; physiography; geology; physical oceanography; socioeconomics; ecosystem

model; Mississippi-Alabama Shelf; DeSoto Canyon; shelf; estuarine; hydrography; barrier

islands.

Marine Ecosystems 65
C,NTr(At. QUIP OP MIXICO QIOK LOUISI AN A MORGAN CITY TIlE TUOCALOO8A TREND STUDY AREA. - 0 25 50 1

0 25 50 75 00 IUL
REPORT TITLE: Southwest Florida Shelf Benthic Communities Study, Year 5 Annual

Report. Vol. I, Executive Summary; Vol. Il, Technical Discussion; Vol. Ill, Appendices.

MMS PUBLICATION NUMBER: MMS 86-0074.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico.

BACKGROUND: The Southwest Florida Shelf Benthic Communities Study Program

commenced in 1980 to investigate the location, nature, and extent of benthic communities

across the southwest Florida shelf. The first three years sought to provide baseline

information, geophysical and biological habitat mapping and classification of substrates and

projection of relative coverage across the shelf in water depths of 20 to 200 m. The next

two study years sought to more accurately predict the impacts of oil and gas activities on

the southwest Florida shelf. More information on ecosystem dynamics and physical factors

was needed. The present report includes the results of the fourth and fifth year field

efforts.

OBJECTIVES: (1) To compare and contrast the community structure of both live-bottom

and soft-bottom fauna and flora to determine the differences and similarities between them

and their dependence on substrate type; (2) to determine and compare the hydrographic

structure of the water column and bottom conditions; (3) to determine and compare

sedimentary characteristics and estimate sediment transport; and (4) to relate differences in

biological communities to hydrographic, sedimentary, and geographic variables.

DESCRIPTION: Study Years 4 and 5 of the Southwest Florida Shelf Ecosystem Study

were designed to provide seasonal data for selected live-bottom and hard-bottom stations

and supplemental data for soft-bottom stations. During Year 4, two station groups were

sampled. Group I Stations (located in less than 20 m water depths) consisted of five

soft-bottom and five hard-bottom stations. Ten replicate infaunal samples were collected at

each of the soft-bottom stations. Sediment samples and hydrographic measurements were

also collected at each station. Sampling at the hard-bottom stations involved dredging,

trawling, underwater television, benthic still photography, sediments, and hydrography.

Seven other hard-bottom stations, as well as one Group I hard-bottom station, were

selected for detailed biological and physical dynamics studies. During Year 4, five of these

stations, designated as Group II were sampled similarly. In situ instrument arrays were

installed at these stations. The arrays were equipped with 10 sets of artificial setting

plates, three sets of sediment traps (0.5, 1 .0, and 1 .5 m) above the bottom, and a current

meter capable of measuring current velocity and temperature. Two arrays also had wave

and tide gauges and all but one, the deepest station, had time-lapse camera/strobe

systems. Arrays were retrieved and serviced at three month intervals.

Field efforts during Year 5 included intensive quarterly sampling of the five Group II hard

bottom stations and three other stations. These stations were located in water depths

ranging from 13 to 1 25 m. Triangle dredge tows were conducted at only two new stations

of the eight. Also, seven of the eight arrays were equipped with time-lapse cameras. At

each station, conductivity, salinity, temperature, pH, dissolved oxygen, and transmissivity

were recorded at three depths (near-surface, mid-depth, and near-bottom) using a CSTD

sonde. Niskin bottle casts were also made at each station to provide a check on the CSTD

Marine Ecosystems 67
measurements. Two new transects were surveyed with underwater television and side-scan

sonar to supplement habitat mapping efforts completed in previous years. Transect X-1 ran

from the Tortugas Shoals southwest to a depth of 100 m; Transect X-2 ran north-south

through Station 55 at an average water depth of 27 m. Underwater television surveys were

conducted with a black and white stereo video system at seven stations. Density and

percentage cover estimates of attached and/or motile biota were made. From trawl

collections, selected fish species were analyzed for reproductive condition and stomach

contents analysis.

SIGNIFICANT CONCLUSIONS: The physical environment of the southwest Florida shelf

changed with depth across the shelf. Tidal currents and surface wave orbital motion were

most responsible for sediment resuspension and transport in shallow (50 m) waters. Loop

Current intrusions and tropical storms exerted significant influence on shelf circulation.

Biological communities were distributed as mosaics reflecting the patchy nature of the

substrate. On sandy bottoms, starfish, conch, and sand dollars were prevalent. Sponges,

corals, and other organisms protruded through the sand in some areas providing habitat for

other invertebrates and fishes. Attached biota, such as corals (soft and stony) and massive

sponges, were numerically dominant on hard-bottoms. Settling plates did not provide

information on the structure of the actual recovery of benthic communities (i.e., corals,

sponges, octocorals). There was no obvious temporal variability in the abundance of most

benthic organisms (except for algae) at most stations.

STUDY RESULTS: Near-bottom currents at the shallow stations on the southwest Florida

shelf were dominated by semidiurnal components of the tides. The diurnal component

began to predominate in deeper waters. Power spectra for summer and winter currents

were similar. Currents at the deeper stations were less consistent with respect to direction,

while currents at shallower stations exhibited considerable constancy, usually setting to the

south or southeast at less than 2 cm sec1. The current regime was affected by two

phenomena; Loop Current eddies intruding onto the shelf, and passage of major storms.

Sediment resuspension and transport was promoted by combined effects of wind-driven

currents, tidal currents, and surface wave-induced orbital velocities. Periodically recurring

storms did not cause significant amounts of sediment movement or resuspension at depths

exceeding 50 m. Stations with the greatest amount of sediment resuspension were also

where wave-induced orbital motion exceeded 20 cm sec1. In general, energy penetration,

light intensity, sediment deposition, turbidity obscurations, and wave orbital velocities at the

bottom were highest at the stations located in 1 3 m water depths.

Biological communities reflected the nature of the substrate. Stations located on hard

substrate revealed the most attached biota (gorgonians and sponges) and fishes. On hard

bottoms, corals, sponges and algae grow, providing shelter for invertebrates and fishes.

Settling plates were fouled most heavily at shallow stations where the most common

organisms were hydroids, barnacles, bivalves, bryozoans, ascidians, and serpulids. In

deeper water, serpulids were the most abundant settling organisms. The instrument arrays attracted a variety of fishes including jewfish, snappers, and grunts.

STUDY PRODUCT(S): Danek, L. J. and G. S. Lewbel. 1986. Southwest Florida Shelf

Benthic Communities Study, Year 5 Annual Report. Vol. I, Executive Summary. A final

68 Marine Ecosystems
report by Environmental Science and Engineering, Inc. and LGL Ecological Research

Associates, Inc. for the U.S. Department of the Interior, Minerals Management Service Gulf

of Mexico OCS Region, Metairie, LA. MMS Report 86-0074. Contract No.

14-12-0001-30211. 47 pp.

Danek, L. J. and G. S. Lewbel. 1986. Southwest Florida Shelf Benthic Communities Study, Year 5 Annual Report. Vol. II, Technical Discussion. A final report by Environmental

Science and Engineering, Inc. and LGL Ecological Research Associates, Inc. for the U.S.

Department of the Interior, Minerals Management Service Gulf of Mexico OCS Region,

Metairie, LA. MMS Report 86-0075. Contract No. 14-12-0001-30211. 561 pp.

Danek, L. J. and G. W. Lewbel. 1986. Southwest Florida Shelf Benthic Communities

Study, Year 5 Annual Report. Vol. III, Appendices. A final report by Environmental Science

and Engineering, Inc. and LGL Ecological Research Associates, Inc. for the U.S. Department

of the Interior, Minerals Management Service Gulf of Mexico OCS Office, Metairie, LA.

MMS Report 86-0076. Contract No. 14-12-0001-30211. 506 pp.

STUDY TITLE: Southwest Florida Shelf Reef Trend Study - Year 2.

COMPLETION DATE OF REPORT: September 1986.

CUMULATIVE PROJECT COST: $992,137.

KEY WORDS: Eastern Gulf; Southwest Florida Shelf; biology; baseline; hydrography; hardbottom; infauna; sediment; epifauna; videotapes; benthic photographs; currents; eddy; Loop

Current; faunal zones; habitat; colonization.

Marine Ecosystems 69
EqgQ I 83S/UTV TRANSECT o - SOFTBOTTOM 8TATIONS - HARDBOTTOM STATIONS BOUTFIWEST FLORIDA SHELF BENTHIC COMMUNITIES STUDY YEARS FOUR AND FIVE 8AMPLINQ STATIONS
REPORT TITLE: Gulf of Mexico Continental Slope Study Annual Report, Year 2.

MMS PUBLICATION NUMBER: MMS 86-0089, 86-0090, 86-0091.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico;

Western Gulf of Mexico.

BACKGROUND: In 1983 (Year I), the U.S. Department of the Interior initiated a four-year

study program to investigate the chemical, physical, and biological aspects of the

continental slope of the northern Gulf of Mexico. This report details the findings of the

second study year, an extension of the Year I effort.

OBJECTIVES: (1) To determine the abundance, structure, and distribution of animal

communities in the deep sea in the Gulf of Mexico; (2) to determine the hydrographic

structure of the water column and bottom conditions at selected sites within the study area;

(3) to determine and compare sedimentary characteristics at selected sites within the study

area; (4) to relate differences in biological communities to hydrographic, sedimentary, and

geographic variables; (5) to assess seasonal changes in deep-sea biological communities in

terms of abundance, structure, animal size, and reproductive state; and (6) to measure

present levels of hydrocarbon contamination in deep-sea sediments and selected animals

prior to, and in anticipation of, petroleum resource development beyond the shelf-slope

break.

DESCRIPTION: All sampling efforts were confined to the northern Gulf of Mexico, north of

27°N Lat, where physical, chemical, and biological characteristics of the water column and

seafloor were obtained. One transect, perpendicular to the slope and comprised of five

stations, was located in each of the three Gulf of Mexico Planning Areas (Eastern, Central,

and Western). Cruises were conducted to examine possible effects of seasonal changes,

and stations were located on transects in a sequence of increasing depth. During Cruise I

(November 1983), only the Central Transect was sampled at five stations (water depths of

329, 786, 850, 1,440, and 2,450 m). During Cruise II (April 1984), these Central stations

were sampled, and five stations on the Western Transect at 342, 653, 828, 1,413, and

2,314 m water depths, and five stations in the Eastern Transect at water depths of 367,

622, 828, 1,172, and 2,857 m were sampled. During Cruise III (November 1984), 12

stations were sampled, all on the Central Transect, at seven intervening depths as well as

the original five. Field sampling consisted of taking water column measurements and

sampling bottom sediments for physical/chemical characteristics, meiofauna, macroinfauna,

and collecting and photographing demersal fishes, epifauna, and macroinvertebrates and

their habitat. Hydrographic measurements included continuous and discrete samples.

Discrete sampling employed a 12-bottle rosette sampler, which provided water samples for

temperature, salinity, dissolved oxygen, and particulate organic carbon (POC).

Transmissometry profiles were taken during each cruise. For sediment sampling, six

replicate box cores (24.5 x 24.5 x 44 cm) were taken at each of the Central Transect

stations during both cruises; three replicates were taken at each of the Eastern and Western

sampling stations. Undisturbed and uncontaminated sediment samples for analysis of

hydrocarbons, grain size, carbonate, and total organic carbon, meiofauna, and infauna were

subsampled from each box core. Meiofauna were defined as those infaunal organisms

passing through a 0.3 mm sieve but retained on a 0.63 mm sieve. Epifauna,

Marine Ecosystems 71
macroinvertebrates, and demersal fishes were collected using a 9-rn, semi-balloon trawl with

3.8 cm stretch mesh and 1 .3 cm cod end mesh. A single haul was taken at each station.

Benthic photography was achieved using a Benthic Underwater Camera System (a Benthos

35-mm camera mounted on a sled equipped with a pinger operated altimeter). In the

laboratory, sediments were analyzed for grain size, organic carbon, and carbonate carbon

content. Carbon isotopic analyses were performed on sediments and selected organisms to

determine carbon source. High molecular weight hydrocarbons in macroepifauna, infauna,

fishes, and sediments were determined using total scanning florescence followed by gas

chromatography/mass spectroscopy. Benthic photographs were processed using a

microcomputer driven digitizer.

SIGNIFICANT CONCLUSIONS: Petroleum input was greatest on the Central Transect, but

all values on all transects were low. Natural hydrocarbon seepage was considered the major

source of petroleum hydrocarbons in sediments of the central and western Gulf of Mexico.

Faunal zonation patterns inferred during this study generally agreed with existing schemes.

STUDY RESULTS: Hydrographic measurements at all stations revealed the expected

layering of water masses based on previous studies: Tropical Atlantic Central Water (oxygen

minimum); Antarctic Intermediate Water (nitrate maximum, phosphate maximum, and

salinity minimum); Caribbean Water (silicate maximum); and Gulf Deep Waters. Sediments

along all three transects contained a mixture of petrogenic, terrigenous, and planktonic

hydrocarbons. In general, sediment hydrocarbons were only present in low concentrations,

especially at the Eastern Transect. The dominant normal alkane between n-C15 and n-C22

was variable; the dominant between n-C23 and n-C32 was consistently either n-C29 or n-C32.

Qualitatively, alkane distribution was similar at all sites sampled. Hydrocarbon

concentrations in macroinvertebrates and demersal fishes of the slope exhibited considerable

variability. Shrimps and crabs had the lowest occurrence of hydrocarbons in muscle while

fish had the highest. Tissue hydrocarbons were predominated by pristine (n-C17, n-C15, and

n-C19) which are primarily planktonic in origin. Sources of these hydrocarbons include

plankton input, terrestrial input of straight-chain biowaxes, and petroleum input. Extractable

organic matter, a composite material derived from both biogenic and petroleum sources,

was found in low concentrations on all transects except Western Transect Station 1.

Carbon isotope measurements made on vent-type organisms (bivalves, tubeworms, and

gastropods) were lighter (-27 to -37%) than other benthic slope organisms (crabs, shrimps).

These differences were attributed to the chemoautotrophic synthesis occurring symbiotically

in the vent animals.

Meiofaunal densities decreased with increasing water depth. Collections were numerically

dominated by nematodes followed by harpacticoid copepods, polychaetes, ostracods, and

kinorynchs. Macrofaunal densities were maximum in the Archibenthal and Upper Abyssal

Zones. An average of 65% of the species are confined to the Upper Abyssal Zone.

Polychaetes were the most speciose group followed by the Tanaidacea and Isopoda. One

hundred and four crustacean species were collected along all three transects. An average of

70% of the crustacean species occurred at depths in excess of 1,000 m. Of the

echinoderms collected in the trawl, asteriods and ophiuroids accounted for about 70% of

the total. Only 60% were collected below 1 ,000 m water depths. About 94% of the

holothurians collected occur below 1,000 m water depths. A total of 112 species of

demersal or benthopelagic fish in 42 families was collected on the three transects.

72 Marine Ecosystems
Thirty-two of these species were represented by the collection of a single specimen. A

preliminary faunal zonation scheme based on cluster analysis of megafaunal collections was

proposed. Prominent vent and seep megafauna observed in benthic photographs included

vestimentiferan tube worms Riftia, Escarpia, and Lameiibrachia and vesicomyid clams of the

genera Ca/yptogena and Vesicomya.

STUDY PRODUCT(S): LGL Ecological Research Associates, Inc. and Texas A&M

University. 1986. Gulf of Mexico Continental Slope Study Annual Report, Year 2. Vol. I,

Executive Summary. A final report for the U.S. Department of the Interior, Minerals

Management Service Gulf of Mexico OCS Office, Metairie, LA. MMS Report 86-0089.

Contract No. 14-12-0001-30212. 23 pp.

LGL Ecological Research Associates, Inc. and Texas A&M University. 1 986. Gulf of Mexico

Continental Slope Study Annual Report, Year 2. Vol. II, Primary Volume. A final report for

the U.S. Department of the Interior, Minerals Management Service Gulf of Mexico OCS

Office, Metairie, LA. MMS Report 86-0090. Contract No. 14-12-0001-30212. 220 pp.

LGL Ecological Research Associates, Inc. and Texas A&M University. 1 986. Gulf of Mexico

Continental Slope Study Annual Report. Year 2. Vol. III, Appendices. A final report for the

U.S. Department of the Interior, Minerals Management Service Gulf of Mexico OCS Office,

Metairie, LA. MMS Report 86-0091. Contract Nb. 14-12-0001-30212. 327 pp.

STUDY TITLE: Northern Gulf of Mexico Continental Slope Study-Year 2.

COMPLETION DATE OF REPORT: August 1986.

CUMULATIVE PROJECT COST: $2,224,893.

KEY WORDS: Eastern Gulf; Central Gulf; Western Gulf; biology; hydrography; physical

oceanography; biology; hydrography; sediment; seasonality; community; benthos;

hydrocarbons; slope; fish; infauna; epifauna; benthic photographs; faunal zones.

Marine Ecosystems 73
LOUISIANA MORGAN S CITY I, KEY MAP PE 5AC.LA 

- 1I S 'I SS S S CtHTRAI. OUI.F OF MIXICO pItaloN SS MIS M S IASTCpIN S )U. t4 I I I S SAMPLING STATIONS FOR THE GULF OF MEXICO CONTINENTAL SLOPE STUDY, YEAR 2. fi. S 

0 0$ $0 TS 
REPORT TITLE: Final Report on the Baseline Environmental Survey of the MAFLA Lease

Areas.

MMS PUBLICATION NUMBER: Contract No. 08550-CT4-1 1.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico.

BACKGROUND: Impending oil and gas exploration of the Mississippi-Alabama-Florida

(MAFLA) Outer Continental Shelf (OCS) prompted the U.S. Department of the Interior to

initiate pre-impact marine environmental assessments of the region. This study concerns

baseline investigations conducted during 1974 on the MAFLA/OCS.

OBJECTIVES: (1) To obtain pre-drilling information on hydrocarbon and trace metal levels

in the water column, sediments, and benthic organisms within the MAFLA region; and (2) to

characterize biological, chemical, and physical parameters of the water column and seafloor

in the MAFLA region.

DESCRIPTION: The study area included the MAFLA OCS from 89°W long (south of

Pascagoula, Mississippi) south along the inside of the 200-rn isobath to approximately

27°30'N lat (west of Clearwater, Florida). Sampling efforts during May and June 1974

were concentrated near five separate lease block areas on the MAFLA shelf. Sediment

samples were taken at 65 stations with a box corer (21.5 x 30.5 cm). Forty-three stations

were established for diver surveys. Divers collected photographic (still photographs and

video) data and samples of epibiota. Capetown dredge samples were taken at each dive

station. Zooplankton were collected using 0.5-rn Nitex nets (0.202-mm mesh) towed in

surface, mid-depth, and bottom waters for 1 5 mm each. Water samples were obtained at

each station using 30-I Niskin bottles. Expendable bathythermograph and salinitytemperature-depth casts were made at each station. In the laboratory, sediment samples

were sieved, separated into grain size fractions, and examined for carbonate content, clay

mineralogy, and skeletal fragments. Trace metal (cadmium, chromium, copper, iron, lead,

and nickel) concentrations were determined by atomic absorption spectrophotometry.

Barium and vanadium were determined by neutron activation analysis. Gas chromatography was used to analyze water, sediments, benthic organisms, and zooplankton for

high molecular weight hydrocarbons. Prepared extracts from water and sediment samples

were analyzed for adenosine triphosphate with a scintillation counter. Water samples were

also analyzed for dissolved oxygen, particulate and dissolved organic carbon, dissolved low

and high molecular weight hydrocarbons, particulate hydrocarbons, suspended matter, trace

metals, phytoplankton, chlorophyll, and zooplankton using standard techniques.

SIGNIFICANT CONCLUSIONS: Petrogenic hydrocarbons were not detected in sediments,

benthic organisms, or water column phases on the West Florida Shelf. Petroleum-derived

hydrocarbon contamination was evident on the Mississippi- Alabama Shelf. This area was

characterized by fine fluvial sediments and low diversity epibiotic assemblages. Input from

the Mississippi River was the most significant hydrographic feature in this area. Carbonate

sediments and high-relief features (Florida Middle Ground) of the West Florida Shelf

supported diverse epibiotic communities. Trace metal concentrations were below

contamination levels for all areas and organisms.

Marine Ecosystems 75
STUDY RESULTS: On the West Florida Shelf, sediments were high in carbonate content

(ca. 80%) and the predominant clay mineral was kaolinite. Calcareous skeletal remains of

annelids, bryozoans, echinoids, foraminiferans, and molluscs were major contributors to the

carbonate fraction. To the west of Cape San Bias, fine quartz sands, silts, and clays

(montmorillonite) were prevalent. Mississippi River influence was responsible for these

characteristics. The aliphatic n-alkanes and isoprenoid ratios from sediments of the

Mississippi-Alabama Shelf were indicative of petrogeneous contamination. Hydrocarbons

from the West Florida Shelf were of biogenic origin. There was no appreciable trace metal

contamination in any of the MAFLA sediment samples. Copper and vanadium were

concentrated in crustaceans and tunicates, respectively. Sponges were enriched with

nickel. Sediment trace metal concentrations were correlated with ambient iron content.

Photographic and dredge samples yielded the following epibiotic groups and number of taxa:

sponges (260), algae (154), crustaceans (107), molluscs (107), echinoderms (50), hard

corals (24), and soft corals (19). Substrate variety dictated epibiotic diversity and relative

abundance. The richest sedimentary biotopes within the MAFLA region occurred on the

West Florida Shelf. Florida Middle Ground rock outcrops supported diverse epibiotic

communities containing many Caribbean elements. Impoverished epibiotic communities

inhabited the Mississippi-Alabama Shelf where riverine inputs (i.e., freshwater discharges)

exerted continuous natural stress. Infaunal samples were numerically dominated by

polychaetes represented by 191 species and 10,020 individuals. A total of 4,281 molluscs,

3,084 gastropods, 1 90 benthic foraminiferans, and 90 scaphopods were reported.

Hydrocarbon contents of benthic organisms were biogenic (i.e., pristane and squalene) and

no n-alkanes resembling Gulf crudes were present. Zooplankton biomass ranged from 5 to

60 mg m3. Bivalve larvae, calanoid copepods, fish larvae, gastropod veligers, Globigerina,

ostracods, pteropods, shrimp larvae, and tunicates were representative zooplankton. A lack

of consistent relationships between concentrations of aliphatics and aromatics in the water

column and plankton was observed. Diatoms contributed the highest cell numbers in the

shelf phytoplankton fraction and reached maximum values in coastal waters.

STUDY PRODUCT(S): State University System of Florida, Institute of Oceanography.

1 978. Final Report on the Baseline Environmental Survey of the MAFLA Lease Areas. A

final report for the U.S. Department of the Interior, Bureau of Land Management Gulf of

Mexico OCS Office, New Orleans, LA. NTIS No. PB293-913/AS. Contract No.

08550-CT4-11. 190 pp.

STUDY TITLE: MAFLA OCS Baseline Study, FY 1 974.

COMPLETION DATE OF REPORT: April 1 978.

CUMULATIVE PROJECT COST: $961,278.

76 Marine Ecosystems
KEY WORDS: Eastern Gulf; Central Gulf; Mississippi; Alabama; Florida; West Florida Shelf;

Mississippi-Alabama Shelf; Florida Middle Ground; baseline; hydrocarbons; trace metals;

sediment; water column; tissue; zooplankton; hydrography; phytoplankton; shelf;

photographs; epifauna.

Marine Ecosystems 77
- ii. LOUISIANA .1 MORGAN CITY OULP Or ixico mlOIOH £ASTEH t4 GENERAL SAMPLING AREAS FOR THE MAFLA OCS BASELINE STUDY. FY 1974. S6 PA N A MA CITY 0 26 60 76 
REPORT TITLE: Final Report on the Quality Control of Trace Metal Analysis for the MAFLA

Baseline Environmental Survey.

MMS PUBLICATION NUMBER: Contract No. 08550-CT4-1 5.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico.

BACKGROUND: The importance of understanding and quantifying the baseline chemical

composition of water, sediments, and fauna of an area is well recognized, particularly as it

relates to assessing potential impacts associated with offshore oil and gas development

activities. Because large baseline environmental study programs have often involved

chemical analyses by several independent laboratories, quality control procedures must be

established to insure that analytical results are comparable between analytical facilities. To

accomplish this objective, the present study effort was initiated in support of the

Mississippi-Alabama-Florida (MAFLA) Outer Continental Shelf (OCS) Baseline Study to

provide appropriate quality control of the trace metals aspects of the program.

OBJECTIVES: (1) To establish a comprehensive quality control program in support of the

trace metal phase of the MAFLA OCS Baseline Study program.

DESCRIPTION: Five types of marine environmental samples, chosen at random from

samples analyzed by the prime chemical analysis contractor, were submitted for quality

control verification. Sample types included surficial bottom sediments, dissolved and

suspended metals in the water column, and faunal samples (i.e., zooplankton, benthic

invertebrates). A total of 35 sediment samples, 15 filtered water samples, 15 suspended

particulate-matter samples, 1 5 zooplankton samples, and 20 benthic invertebrate samples

were tested.

A total of eight different metals or trace metals were determined. Measured metals or trace

metals included barium (Ba), cadmium (Cd), lead (Pb), vanadium (V), nickel (Ni), copper (Cu),

chromium (Cr), and iron (Fe). Samples were analyzed by flame and/or flameless atomic

absorption spectrophotometry.

SIGNIFICANT CONCLUSIONS: The metals present in the greatest quantity in the MAFLA

sediments included calcium (20%), magnesium (3%), iron (0.7%), aluminum (0.5%), sodium

(0.5%), and potassium (0.15%). Average heavy metal concentrations in the sediments

were 4,877 ppm for iron; 22.7 ppm for barium; 15.4 ppm for chromium; 11 .4 ppm for

vanadium; 6.1 ppm for nickel; 4.7 ppm for lead; 1.8 ppm for copper; and 0.086 ppm for

cadmium. Percent recovery was lowest in samples analyzed by flameless atomic absorption

spectrophotometry techniques. Good recoveries were obtained for chromium, copper, lead,

nickel, and vanadium. Iron was present in the highest concentration in seawater samples

analyzed. By comparison, nickel was highest in suspended particulate matter. The lowest

concentrations were measured for cadmium and chromium in these latter two types of

samples, respectively. Iron was also highest in benthic invertebrates, occurring at an

average concentration of over 1 5,000 ppb. Lead was present at the lowest average

concentration of 23 ppb. Similar trends were observed for metals in zooplankton.

Marine Ecosystems 79
STUDY RESULTS: In sediment samples collected from the MAFLA survey area, the

analysis for barium content was impossible to perform by flame atomic absorption

spectrophotometry due to interference from calcium. Therefore, analysis was performed by

graphite furnace atomic absorption techniques. Even this technique resulted in some loss of

barium due to a need to dry and char the sample for longer periods of time to eliminate

interference from smoking of the sample during testing. Vanadium was easily determined by flame atomic absorption spectrophotometry. A 20% average difference was observed

between aqueous versus matrix-matched standards. Cadmium was analyzed by flameless

graphite furnace because the detection limit by flame atomic absorption spectrophotometry

was exceeded. A 25% loss was observed during dry and char steps. Lead was measured

by flame atomic absorption spectrophotometry. Comparison of data found no difference

between aqueous and matrix-matched standards. Analyses for nickel required a matrix

correction and a nonabsorbing wavelength reading. The difference between aqueous and

matrix-matched calibration was approximately 10%. Copper determinations required matrixmatching of standards having a 1 5 to 20% increase in copper compared to aqueous

standard calibration. For chromium, values obtained with matrix-matched standards were

10% lower than for aqueous standards. Average heavy metal concentrations in the

sediments were 4,877 ppm for iron; 22.7 ppm for barium; 15.4 ppm for chromium; 11 .4

ppm for vanadium; 6.1 ppm for nickel; 4.7 ppm for lead; 1.8 ppm for copper; and 0.086

ppm for cadmium. The presence of iron in greater than trace amounts proved to be the only

difficulty encountered for sediment analysis of this element. Large dilutions were necessary

in order to use the linear portion of the calibration curve.

With regards to quality control, it was determined that the analyses for cadmium,

chromium, copper, lead, nickel, and vanadium were "in control". Iron analyses were not

classified (i.e., "in control" versus "out of control") since iron is not a trace component of

sediments. It was not possible to apply such decisions to barium since 60% of the barium

was lost during flameless atomic absorption spectrophotometry. Recovery of metals in

spiked samples ranged from 50.8 to 1 38.1 % for the various elements. Barium gave the

lowest recovery, with 99.7% recovery measured for chromium in a matrix-matched sample.

Statistical analyses indicated that duplicate analyses were performed with good

reproducibility. An average variability of 27.9% was obtained. The highest variability was

with cadmium (61.2%) and the lowest with iron (9.9%).

The order of decreasing dissolved metal content was Fe>Ba>V=Pb>Cr>Cu>Ni>Cd for

the 1 5 water samples analyzed. The trace metal content for sediments was

Fe>Ba>Cr>V>Ni>Pb>Cu>Cd. Chromium and lead showed the most significant difference between the two groups. For suspended particulate matter, metals

concentrations in descending order were Ni>Fe>Cu>Ba>Pb>Cd>Cr. The average

concentration of vanadium was less than the detection limit of 5 ppb. Significant

concentrations of nickel were measured for the suspended particulate matter as compared

to dissolved nickel. Copper averaged 23.0 ppb in suspended particulate matter versus

2.6 ppb in seawater.

Because sample weight and digestion volume were not available for the analysis, a rigorous

interpretation of benthic invertebrate data was not feasible. Large amounts of iron, nickel,

and vanadium were found in these samples while lead content was low. The order of

elements in these samples, ranging from high to low concentrations, was

80 Marine Ecosystems
Fe> Ni> V> Ba> Cu> Cd> Cr> Pb. Copper concentrations in zooplankton were similar to

those for benthic invertebrates. Iron was present at the highest levels of the eight trace

metals, while lead was lowest. Barium was higher than that found in the benthic

organisms.

STUDY PRODUCT(S): Gulf South Research Institute. 1975. Final Report on the Quality

Control of Trace Metal Analysis for the MAFLA Baseline Environmental Survey. A final

report for the U.S. Department of the Interior, Bureau of Land Management Gulf of Mexico

OCS Office, New Orleans, LA. Contract No. 08550-CT4-1 5. xvi + 1 71 pp.

STUDY TITLE: Trace Metal Quality Control Analyses.

COMPLETION DATE OF REPORT: August 1975.

CUMULATIVE PROJECT COST: $29,091.

KEYWORDS: Eastern Gulf; Central Gulf; chemistry; trace metals; sediment; water column;

fauna; zooplankton; invertebrates; benthos; quality assurance; interlaboratory comparison;

spectrophotometry; Mississippi; Alabama; Florida; Gulf of Mexico Region.

Marine Ecosystems 81
. LOUISIANA IIORGAN CITY I I KEY MAP LFJO, 11⁄4 CEHTAL QUt. OT UXICO 61010N 11⁄4 EA&TtIH L4 0 II 60 l 00 OIL

0 16 60 76 

GENERAL SAMPLING AREAS FOR THE MAFLA OCS BASELINE STUDY. REPRESENTATIVE SAMPLES WERE COLLECTED FROM THANALYZED DURING AN EVALUATION OF QUALITY CONTROL METHODOLOGY EMPLOYED DURING TRACE METAL ANALYSIS. 
REPORT TITLE: Multivariate Analysis of the MAFLA Water Column Baseline Data.

MMS PUBLICATION NUMBER: Contract No. 08550-CT5-27.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico.

BACKGROUND: The Mississippi, Alabama, Florida (MAFLA) environmental baseline studies

sponsored by the U.S. Department of the Interior were intended to provide pre-impact data

to support decisions regarding oil and gas development on the MAFLA shelf. The field

sampling program focused on biotic and abiotic components of the seafloor and water

column. To investigate correlations between zooplankton community and water column

environmental parameters, a follow up study using objective multivariate statistical

techniques was conducted. The use of multivariate analyses allows a reduction of an

otherwise cumbersome data set into smaller, easier understood components.

OBJECTIVES: (1) To determine the relationship between zooplankton community structure

and environmental structure; and (2) to determine the relationship between environmental

pollution (trace metals and hydrocarbons) and zooplankton levels of pollution (trace metals

and hydrocarbons).

DESCRIPTION: The analyses were performed on two multivariate data sets: zooplankton

community variables and environmental variables. Data were collected from five different

lease tract areas on the MAFLA shelf during 1974. The zooplankton community data set

contained 33 taxonomic categories expressed as numbers per m3. The environmental data

set contained physical features of the water column (salinity and temperature) and levels of

various water column pollutants (suspended trace metals and dissolved low molecular

weight hydrocarbons). The analyses were performed separately on data from two different

areas (lease tract areas I, II, III and lease tract areas IV and V). Trace metal data were

analyzed using the following techniques: suspended trace metals with multivariate

regression, factor analysis, and canonical correlation; zooplankton trace metal analyses with

multivariate regression and canonical correlation; and zooplankton trace metal residuals with

canonical correlation. Multivariate regression and canonical correlation were used for

zooplankton hydrocarbon analyses from both lease tract areas. Zooplankton category

association analysis was completed using factor analysis.

SIGNIFICANT CONCLUSIONS: In the MAFLA region, a complex set of interacting variables

govern variability in zooplankton populations. Much of the observed variation can be

attributed to salinity, temperature, depth, and to a much lesser extent, trace metals and

hydrocarbons. Within lease tract areas I, II, and Ill, variation in trace metal concentration

showed no significant correlations with standing crop of zooplankton. Relationships

between zooplankton and water column parameters were best suited as indicators of water

mass characteristics. Zoopiankters were classified as positive, neutral, and negative

concentrators in terms of trace metal concentrations. Trace metal levels were higher in

lease tract areas IV and V. This was undoubtedly due to the proximity of the Mississippi

River. The relationship with zooplankton community structure and trace metal levels in the

MAFLA region was not significant. Future studies of this nature should strive for

synopticity of sampling efforts for zooplankton and environmental parameters.

Marine Ecosystems 83
STUDY RESULTS: The most important factors influencing zooplankton community

structure were salinity, temperature, and water mass origin. Approximately 45% of the

zooplankton community variation was correlated with various aspects of the environmental

variation. The most important environmental factors related to the structure of the

zooplankton community were inshore-offshore considerations and the surface to bottom

layering of the water column. Environmental variables related to inshore-offshore factors

were station depth, net depth range, and salinity range which were all associated with

deeper offshore stations. Surface to bottom layering was expressed by a group of

environmental variables including net depth, temperature, temperature range, and salinity

range. This was exemplified by the calanoid copepods Acartia, Centropages, and

Euca/anus, and chaetognaths which were negatively correlated with salinity and station

depth and positively related to temperature and salinity range. Species assemblages found

to be correlated with the environment were regulated by depth factors or changes in salinity

and temperature. This indicates that the zooplankton community is being influenced by

similar forces controlling the water column environment. Results from canonical correlations

indicated a strong relationship between the zooplankton community and the water column

environment.

Suspended trace metal variation in lease tract areas I, II, and Ill did not explain zooplankton

community variability. In lease tract areas IV and V, factor analysis revealed trace metals

were more important features of the environment, but this was expected due to the

proximity of the Mississippi River, a source of industrial pollution. Despite this, trace metals

were not important in predicting zooplankton community structure. The only appreciable

relationships were with lead, cadmium, and iron.

Canonical correlation between suspended trace metals and trace metals concentrated in the

zooplankters indicated three types of zooplankter in relation to trace metal concentration:

positive concentrators (the larvacean Oikopleura and nickel); negative concentrators (the

copepod Centropages and nickel); and those with no particular relationship. The source of

variation in trace metal levels in a zooplankter depends on the type of zooplankter and its

physiological mechanisms for handling trace metals.

The variation of hydrocarbon measurements in zooplankton was greatly influenced by the

category composition of the population. Canonical correlation total redundancy for lease

tract areas I, II, and Ill was 49.61 %, and 49.38% for lease tract areas IV and V, indicating

that approximately one half of the hydrocarbon variation in zooplankters was accounted for

by the categories of zooplankton encountered.

STUDY PRODUCT(S): Maturo, F. J., Jr., J. W. Caidwell, W. Ingram, Ill, and F. L. Hearne.

1975. Multivariate Analysis of the MAFLA Water Column Baseline Data. A final report by

the University of Florida Marine Laboratory for the U.S. Department of the Interior, Bureau

of Land Management Gulf of Mexico OCS Office, New Orleans, LA. NTIS

No. PB8O-201692. Contract No. 08550-CT5-27. 110 pp.

STUDY TITLE: MAFLA OCS Multivariate Analysis of Water Column Data.

COMPLETION DATE OF REPORT: September 1975.

84 Marine Ecosystems
CUMULATIVE PROJECT COST: $22,063.

KEY WORDS: Eastern Gulf; Central Gulf; Mississippi; Alabama; Florida; Mississippi River;

baseline; zooplankton; trace metals; hydrocarbons; water column; hydrography; tissue;

shelf; multivariate statistics; community.

Marine Ecosystems 85
MORGAN . CITY OU%.P OP MEXICO tOION GENERAL SAMPLING AREAS FOR THE MAFLA WATER COLUMN BASELINE DATA, 1974. 

0- 00 10 11 

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REPORT TITLE: lchthyoplankton Abundance and Diversity in the Eastern Gulf of Mexico.

MMS PUBLICATION NUMBER: Contract No. AA550-CT7-28.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico.

BACKGROUND: Information concerning the early life stages of fishes is important for

management of commercial and recreational fisheries. Early life stages of fishes are subject

to high mortality and may serve as indicators of spawning period and recruitment strength.

To augment environmental baseline information for the Gulf of Mexico, the U.S. Department

of the Interior supported a four-year survey of ichthyoplankton abundance and distribution in

the eastern Gulf of Mexico.

OBJECTIVES: (1) To determine kinds and abundances of fish larvae that occur in the

eastern Gulf of Mexico; (2) to elucidate spatial and temporal spawning patterns of

ecologically and economically important fishes; and (3) to determine environmental variables

correlated with species success.

DESCRIPTION: The survey area extended from 24°45'N to 30°15'N lat, and west off

Florida to 88°W long. Seventeen cruises were conducted from 1971 to 1974 and a total of

869 stations were sampled. Sampling stations were spaced at 28-km intervals and were

parallel to latitude lines. Data recorded included position, depth of tow, volume filtered,

surface temperature, surface salinity, zooplankton volume, total eggs, and total fish larvae.

Collections were made using a 61-cm bongo net and a 1-rn diameter plankton net. Oblique

tows were made to within 5 m of the bottom or to 200 m depth at deep stations. All

ichthyoplankton samples were preserved in 10% formalin in the field, then sorted, counted,

measured, and transferred to 5% buffered formalin in the laboratory. Various statistical and

numerical techniques were used in data analysis, including index of abundance, estimated

total abundance, estimated biomass, and species diversity (Shannon-Weaver), evenness,

species richness (Simpson's), and mortality estimates. Bivariate correlation analysis was

used to examine associations between log10 abundance of selected larval species and

environmental variables.

SIGNIFICANT CONCLUSIONS: Eastern Gulf of Mexico ichthyoplanktonic assemblages

were abundant and diverse. Spawning seasons for many species were discerned. There

was no positive correlation between environmental variables and larval species abundances.

Some species had affinities for the Loop Current.

STUDY RESULTS: A total of 143,034 larvae and 304,620 eggs were collected.

Ninety-one families represented by 161 genera and 173 species were recorded. The 10

most common families, ranked in order of abundance, were Clupeidae (sardines and

herrings), Gobiidae (gobies), Bothidae (left-eyed flounders), Myctophidae (lanternfishes),

Serranidae (seabasses, groupers, and sand perches), Carangidae (jacks and pompanos),

Synodontidae (lizardfishes), Ophidiidae (cusk eels, brotulas), Bregmacerotidae (codlets), and

Labridae (wrasses). Clupeids and gobiids were most common, contributing 35.6 and

15.6%, respectively, to the total catch in waters <lOOm deep. Myctophids were the

predominant larval family in waters >100 m. In this study, 59,701 larvae were identified to

species, which is 41 .7% of all larvae that were collected. Ten species accounted for

Marine Ecosystems 87
46,637 larvae, which is 78.1% of all larvae identified to species. Most common species

were the Spanish sardine Sardinella ancho via, Atlantic thread herring Opisthonema oglinum,

round scad Decapterus punctatus, and the sand perch Diplectrum formosum.

Annual abundances of some common species varied considerably from year-to-year.

Mortality estimates were lowest for short-lived species (clupeids) with higher growth rates,

and highest for robust perciforms (lutjanids, haemulids, and carangids). Biomass estimates

indicate that 0. ogilnum, S. ancho via, and D. punctatus exceeded 100,000 MT. Bluefin

tuna Thunnus thynnus biomass was estimated between 25,000 and 48,000 MT. Total

biomass for pelagic fishes was between 1.5 and 3.0 x 106 MT while total demersal species

biomass was below 1 .0 x 106 MT.

The largest catches of larval fishes were taken during spring and summer, indicating a peak

spawning period. Spring and summer spawners included 0. og/inum, D. punctatus, S.

ancho via, and dusky flounder Syacium papi/osum. Occurrences of D. formosum indicated

year-round spawning while another serranid, the black sea bass Centropristis striata,

spawned from fall to spring. Snappers (Rhombop/ites aurorubens, Lutjanus spp., and

Ocyurus chrysurus), and grouper (Epinephe/us mono) were spring and summer spawners.

Mackerels (Scomberomorus cavalla and S. maculatus) were not common in collections and

probably do not spawn much in the eastern Gulf. Bregmacerotids spawn year-round with

some depth segregation between species.

Diversity estimates did not show appreciable seasonal or north-south differences. Onshore

vs. offshore diversities were different with ichthyoplankton diversity highest in the offshore

zone (>100 m). Evenness was higher at depths >50 m. From the 94 species employed in

the calculations, a mean of 49.8 species per cruise was observed. Diversity estimates could

change if more of the unidentified species (i.e., gobiids) were incorporated. Numerical

dominance by relatively few species of clupeids caused inshore diversity estimates to be

low.

Correlations between abundance of larval fishes and various environmental variables were

generally not significant. Sampling artifacts and temperature and salinity measurement

procedures may have contributed to the lack of correlation. Species exhibiting positive

affinity for the Loop Current included the myctophids Myctophum nitidulum and

Diogenichth ys at/an ticus, go n osto mat i ds Gonostoma elongatum and Vinciguerria nimbaria,

and bregmacerotids Bregmaceros at/an ticus and Bregmaceros Type A.

STUDY PRODUCT(S): Houde, E. D., J. C. Leak, C. E. Dowd, S. A. Berkeley, and W. J.

Richards. 1979. lchthyoplankton Abundance and Diversity in the Eastern Gulf of Mexico.

A final report by Rosenstiel School of Marine and Atmospheric Science, University of Miami

and National Marine Fisheries Service for the U.S. Department of the Interior, Bureau of

Land Management Gulf of Mexico OCS Office, New Orleans, LA. NTIS No. PB299-8391A5.

Contract No. AA550-CT7-28. 546 pp.

STUDY TITLE: Eastern Gulf of Mexico OCS Ichthyoplankton Study, FY 1 977.

COMPLETION DATE OF REPORT: June 1 979.

88 Marine Ecosystems
CUMULATIVE PROJECT COST: $88,851.

KEY WORDS: Eastern Gulf; biology; fish; ichthyoplankton; abundance; distribution;

spawning; Loop Current; hydrography.

Marine Ecosystems 89
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COASTAL STUDIES

These studies compile existing available information utilizing a holistic approach that

identifies functional relationships among natural processes and components of coastal

ecosystems. An ecological characterization study is designed primarily to integrate

environmental and socioeconomic information in a form useful for planning, impact

assessment, and analysis, and to identify research needs. A characterization study is a

tool that will enable decisionmakers to address problems including planning for urban

and industrial developments, determining corridors for pipelines, siting of onshore and

offshore facilities for OCS oil and gas activities, and determining priorities for future

research.

The products of a characterization study are an ecological atlas, ecosystem models, a

narrative report, and an information base or data source appendix. The atlas is a series

of maps and diagrams that depicts biological resources, including habitats; factors of

potential impact, including land use practices, socioeconomic activities, and

environmental perturbations; and ecological processes within the study area. The

ecosystem models delineate structural components, the functional process, and their

integral relationships to physical/chemical processes characteristic of the region. The

narrative report contains descriptions of the study area that emphasize natural

socioeconomic interrelationships, major uses of natural resources, and changes

resulting from human activities. The information base or data source appendix includes

a record of all references, copies of reprints and unpublished information and data

acquired, and a report on the locations and nature of unpublished data not acquired.

Coastal Studies 91
REPORT TITLE: Rare, Threatened, and Endangered Vertebrates of Southwest Florida and

Potential OCS Activity Impacts.

MMS PUBLICATION NUMBER: Contract No. 14-12-0001-30036.

APPLICABLE PLANNING AREA(S): Straits of Florida; Eastern Gulf of Mexico.

BACKGROUND: A consensus of five listings from Federal, State, and private institutions

and organizations have considered 68 southwestern Florida vertebrate species to be rare,

threatened, or endangered. These vertebrate populations could potentially be reduced to

non-sustaining levels by human activities. Leasing of Outer Continental Shelf (OCS) areas

for oil and gas activities increases the potential for man-induced impacts upon sensitive

vertebrate populations. Information necessary to assess population decline is usually

unavailable because of vast amounts of time needed to gather conclusive data. Potential

increased human activity due to oil and gas activities makes it imperative to compile

information and make recommendations concerning these vertebrate populations.

OBJECTIVES: (1) To identify the rare, threatened, and endangered vertebrate species of

southwestern Florida and describe their habitats; (2) to evaluate man-induced and oil and

gas activity impacts on these species.

DESCRIPTION: A list of 68 terrestrial and nearshore vertebrate species considered rare,

threatened, or endangered was compiled from five listings. The General Map of Natural

Vegetation of Florida outlines 1 3 terrestrial habitats that exist within eight southwestern

Florida counties. The habitats were described and the vertebrates that occur within each

habitat were listed. Habitat importance to a particular vertebrate species was determined by

relative animal density or frequency of occurrence within a habitat. The geographic

distribution of vertebrate species by county was determined by calculating the number of

species that occur within a county and expressing that number as a percentage of the total

listed. The percent of the listed species that occur within a habitat type, and the percent of

species for which each habitat is of primary importance, were also calculated. Man-induced

impact on existing populations was represented by calculating the percentage of counties

and habitats under development. Oil and gas activity scenarios were projected. By using

recorded data, potential impacts on vertebrate populations were considered.

SIGNIFICANT CONCLUSIONS: Of the 68 listed vertebrate species, 36 species have broad

ranges and have been recorded in all eight counties. The large range of these species makes

them less susceptible to isolated impacts. The Florida panther is the only vertebrate of the

broad range species to have a declining population. Coastal marine habitats (e.g., mangrove

marsh), which harbor the largest number of rare and endangered vertebrates and species

restricted to one habitat, are most susceptible to oil and gas activity impact. None of the

listed vertebrates have population declines due to natural causes, so efforts should be made

to protect the vertebrates from habitat alteration.

STUDY RESULTS: The list of 68 vertebrate species includes all that have been or would

be affected by habitat alteration in the eight southwestern Florida counties. Of these

vertebrates, 53% are found in all eight counties. The relative small study area (7,200 mi2)

and high mobility of many vertebrates (e.g., birds) probably accounts for the cosmopolitan

Coastal Studies 93
range. Monroe County (Florida Keys) harbors 87% (59 species) of the listed vertebrates and

20% (14 species) are restricted to this county. The Florida Keys, being a string of islands,

allows for some genetic isolation and potential speciation which probably accounts for the

presence of 9 endemic species or subspecies.

Habitat importance, as determined by presence of the listed vertebrates, requires primary

emphasis. Mangrove/salt marsh habitat is occupied by 54% (37 species) of the vertebrates

and is ranked first in importance. Estuaries, everglades marsh, and marl/rock marsh are

second in habitat importance. Coastal and inland wetlands are critical habitats and must be

protected from habitat alteration. Destruction of habitat, direct exploitation, and incidental

disturbances have been indicated as the major causes of population decline. Potential oil

and gas activity in the eight counties can accelerate the increase in these detrimental

factors. Onshore facilities should be located as far from the most critical habitats as

possible.

STUDY PRODUCT(S): Woolfenden, G. E. 1983. Rare, Threatened, and Endangered

Vertebrates of Southwest Florida and Potential OCS Activity Impacts. A final report by the

U.S. Fish and Wildlife Service for the U.S. Department of the Interior, Minerals Management

Service Gulf of Mexico OCS Office, Metairie, LA. NTIS No. PB83-25081 1.

FWS/OBS-82/03. Contract No. 14-12-0001-30036. 74 pp.

STUDY TITLE: Southwest Florida Shelf Coastal Ecological Characterization.

COMPLETION DATE OF REPORT: February 1983.

CUMULATIVE PROJECT COST: $1,090,973.

KEY WORDS: Straits of Florida; Eastern Gulf; Southwest Florida Shelf; Florida; baseline;

biology; endangered species; terrestrial; characterization; habitat; vertebrates; distribution;

impacts; literature review; synthesis.

MAP #30036.7 Unavailable.

94 Coastal Studies
REPORT TITLE: Rare, Threatened, and Endangered Plant Species of Southwest Florida and

Potential OCS Activity Impacts.

MMS PUBLICATION NUMBER: Contract No. 14-12-0001-30036.

APPLICABLE PLANNING AREA(S): Straits of Florida; Eastern Gulf of Mexico.

BACKGROUND: Certain plant populations of southwestern Florida are designated as rare,

threatened, or endangered. Various natural and man-induced factors are responsible for the

designations. An increase in man-induced factors may occur as a result of leasing areas of

the Outer Continental Shelf (OCS) for oil and gas activities. Exploratory drilling may occur,

and consequently oil and gas production and transport and onshore facilities may become a

possibility. The most serious impact of oil and gas activities to southwestern Florida's

plants would be due to oil spills. Baseline information concerning plants of southwestern

Florida coastal counties must be considered so that plant distribution and current status can

be related to natural variability and man-induced effects.

OBJECTIVES: (1) To summarize all published information concerning southwestern

Florida's rare, threatened, and endangered plant species; (2) to describe natural and

man-induced causes of plant rareness; (3) to evaluate impacts of oil and gas activities on

rare, threatened, and endangered plants along the southwestern Florida coast.

DESCRIPTION: A list of 274 plants considered rare, threatened, or endangered in

southwestern Florida was compiled from six listings. The criterion for plant status

designation differed between lists. The Florida Committee on Rare and Endangered Plants

and Animals (FCREPA) list was considered the most complete and up-to-date. The 274

plants were categorized by habitat, of which there were 1 7, and geographical distribution

among eight southwestern Florida coastal counties. Plants on the FCREPA list were also

categorized and expressed as a ratio to the total listing. The biogeographical distribution of

the 274 plants and the FCREPA listed plants were determined by data gathered from various

published accounts. The future extent of man-induced impact was projected by estimating

population growth and area development. Oil and gas activity scenarios were projected

and, by using recorded data (e.g., frequency of oil spills), potential impacts to plant

populations were considered.

SIGNIFICANT CONCLUSIONS: Present Florida habitat is the range extremity for many

plant species, making these particular species very susceptible to extinction. Habitat

requirements for many species are very specific, therefore, habitat alteration by man's

activity may be the most severe impingement on these species. The onset of oil and gas

activities compounds man-induced impacts on plant habitats by increasing onshore

development, water demands, and potential oil spills.

STUDY RESULTS: By expressing the FCREPA listed plants and the total compiled plant

listing as a ratio during habitat and county distribution categorization, similarities and

dissimilarities between lists could be delineated. The lists were quite similar in species

composition within habitats and distribution of species among the eight counties, although

the compiled listing may be overinflated.

Coastal Studies 95
Reasons for plant rareness within the eight counties were discussed. Life histories and

population dynamics are virtually unknown for most plants listed, therefore, most natural

causes of rareness could not be elaborated. The geologically recent exposure of coastal

Florida allowed for colonization of various tropical plant species. Some of these species are

rare due to geographic restrictions and have colonization only in tropical or semi-tropical

localities. Man-induced impact is widespread, ranging from plant collection to habitat

alteration. Land is under constant uptake for agriculture, urbanization, and mining. With

the potential of oil and gas activities, the problem of land uptake and habitat alteration

becomes compounded.

STUDY PRODUCT(S): McCoy, E. D. 1981. Rare, Threatened, and Endangered Plant

Species of Southwest Florida and Potential OCS Activity Impacts. A final report by the U.S.

Fish and Wildlife Service for the U.S. Department of the Interior, Bureau of Land

Management Gulf of Mexico OCS Office, New Orleans, LA. NTIS No. PB82-182452.

FWS/OBS-8 1/50. Contract No. 14-12-0001-30036. 84 pp.

STUDY TITLE: Southwest Florida Shelf Coastal Ecological Characterization.

COMPLETION DATE OF REPORT: November 1981.

CUMULATIVE PROJECT COST: $1,090,973.

KEY WORDS: Straits of Florida; Eastern Gulf; Southwest Florida Shelf; Florida; baseline;

biology; characterization; endangered species; plants; terrestrial; habitat; distribution;

impacts; literature review; synthesis.

MAP #30036.8 Unavailable.

96 Coastal Studies
REPORT TITLE: Alabama Coastal Region Ecological Characterization. Vol. 1, Coastal

Bibliography; Vol. 2, A Synthesis of Environmental Data.

MMS PUBLICATION NUMBER: Contract No. 14-12-0001-30037.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico.

BACKGROUND: Coastal Alabama and adjacent waters are an important industrial,

recreational, and seafood production area in the northern Gulf of Mexico. Discovery of oil

and gas in and around Mobile Bay, development of State-owned and outer continental shelf

fossil fuel reserves, and completion of the Tennessee-Tombigbee Waterway have enhanced

the area and should promote continued urban and industrial expansion. Recognizing the

highly productive area along the Alabama coast and the resource planning to maintain these

areas, the U.S. Fish and Wildlife Service initiated the Ecological Characterization Program for

selected coastal areas.

OBJECTIVES: (1) To summarize all available information on natural resources of coastal

Alabama.

DESCRIPTION: Coastal Alabama lies within the Coastal Plain province and the

Mississippi-Alabama shelf section of the Continental Shelf province. Part of the study was a

literature search and bibliography pertaining to coastal Alabama. The report characterizes

the area with respect to geology, hydrology, climate, plant life, animal life, endangered and

threatened species, and an area-wide conceptual model. The aim of the conceptual

representation is for the information synthesis to present the coastal water environment as

integrated systems of physical, chemical, and biological forces. These representations were

developed to serve as a reference source of known information about coastal Alabama.

SIGNIFICANT CONCLUSIONS: The holistic conceptual model of coastal Alabama as a

single energy system was comprised of two basic units. One unit consisted of four natural

ecosystems and their connective pathways. The second unit consisted of manipulated

subunits such as agricultural ecosystems and urban/industrial systems that require extensive

inputs of external energy. The conceptual model provides a workable hierarchical system

that indicates the interrelationships that exist between natural and modified systems.

Although some areas need further research, the conceptual model may be used as a

management tool for maintaining the balance between individual subunits within the

system.

STUDY RESULTS: Coastal Alabama has four physiographic subdivisions. The southern

pine hills comprise the elevated east and west lateral portion of coastal Alabama. The

alluvial plain, deltaic plain, and coastal lowlands are relatively flat, are adjacent to

Mississippi Sound, and extend along margins of Mobile, Bon Secour, and Perdido Bays.

These flat physiographic subdivisions also extend northward along the Tombigbee and

Alabama Rivers. The coastal boundaries of these relatively shallow bays are defined by

various barrier islands and spits. The Mississippi-Alabama shelf is a triangular area seaward

of the barrier islands and extends from the Mississippi River Delta to the De Soto Canyon.

Coastal Studies 97
Coastal and offshore Alabama are underlain by sediments ranging from pre-Jurassic to

Holocene. These rock units are possibly more than 7,620 m (25,000 ft) thick at the coast

and decrease southward by 1.9 to 9.4 m/km (10-50 ft/mi). The coastal and continental

shelf topography and sedimentation result from tidal and current movements, as well as

alluvial and deltaic progradation and destruction.

The prominent structural geological features along coastal Alabama are the peripheral faults,

Mobile graben, the Citronelle domal anticline, and the Wiggins uplift. Tectonic hazards are

not a problem in coastal Alabama because there are no known active faults.

Oil and gas production is well established in coastal Alabama with developed fields at

Citronelle, Chunchula, Hatter's Pond, and South Carlton. There is a high potential for future

gas and oil production.

Coastal Alabama has a dynamic hydrologic system with the focal point of the system being

Mobile River and Mobile Bay into which it flows. Average yearly (freshwater) discharge

from this system into the Gulf of Mexico is 50 km3 (12 mi3). Flooding is the worst natural

hazard of coastal Alabama and may result from storm surges and heavy rainfall associated

with hurricanes and other tropical storms. Flood discharge has a pronounced effect on

inland and estuarine water salinity and coastal sedimentation. Climatic and physical

oceanographic factors along coastal Alabama are well understood and recorded because of

the extent to which they affect this particular area.

Specific studies of coastal Alabama phytoplankton were lacking, however, an intensive

study of Mobile Bay phytoplankton has been undertaken. Community diversity and species

composition of aquatic vegetation has declined. Habitat types were described and

characterized by associated flora. Animal diversity was high in coastal Alabama where the

fauna included terrestrial, freshwater, saltwater, and brackish water species characteristic of

temperate and subtropical climates. Coastal Alabama has important habitats for many

commercially valuable biota (i.e., shrimp, oysters, and fish). This area maintains a highly

diversified avifauna (greater than 300 species) which is attributed to the multiple habitats

present in coastal Alabama. Fifty-seven mammalian species have been reported from

coastal Alabama. Some flora and fauna are considered endangered or threatened.

The natural ecosystems are functionally composed of producers, consumers, and

decomposers. Energy within the system is transferred and transformed between trophic

levels. This system is considered self-sustaining. The agricultural, urban/industrial, and

associated pathways rely heavily on external energy from other systems illustrating their

independence on natural ecosystems.

98 Coastal Studies
STUDY PRODUCT(S): O'Neil, P. E., M. F. Mettee, E. J. McCullough, L. A. Acker, and D.

W. Wilson. 1982. Alabama Coastal Region Ecological Characterization. Vol. 1, Coastal

Bibliography. A final report by the U.S. Fish and Wildlife Service for the U.S. Department of

the Interior, Minerals Management Service Gulf of Mexico OCS Office, Metairie, LA. NTIS

No. PB83-180661. FWS/OBS-82/21. Contract No. 14-12-0001-30037. 408 pp.

ONeil, P. E. and M. F. Mettee. 1982. Alabama Coastal Region Ecological Characterization.

Vol. 2, A Synthesis of Environmental Data. A final report by the U.S. Fish and Wildlife

Service for the U.S. Department of the Interior, Minerals Management Service Gulf of

Mexico OCS Office, Metairie, LA. NTIS No. PB83-190009. FWS/OBS-82/42. Contract No.

14-12-0001-30037. 346 pp.

STUDY TITLE: Northeastern Gulf of Mexico Coastal Ecological Characterization.

COMPLETION DATE OF REPORT: June 1982.

CUMULATIVE PROJECT COST: $1,185,000.

KEY WORDS: Eastern Gulf; Central Gulf; Alabama; baseline; biology; characterization;

synthesis; bibliography; literature review; coastal zone; terrestrial; geology; physiography;

plankton; birds; commercial fishing; endangered species; literature review; synthesis.

Coastal Studies 99
,r LOUISIANA 1 .','., ) - CENTRAL QULF O MEXICO REQION EAsTERN t5- t4 PEA STUDY AREA FOR THE ALABAMA COASTAL REGION ECOLOGICAL CHARACTERIZATION o-as 60 76 

0 25 60 76 00 KIL
REPORT TITLE: Alabama Coastal Region Ecological Characterization. Vol. 3,

A Socioeconomic Study.

MMS PUBLICATION NUMBER: Contract No. 14-12-0001-30037.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico.

BACKGROUND: This study is one of a series of characterizations produced by the U.S.

Fish and Wildlife Service and jointly funded with the Bureau of Land Management (presently

the Minerals Management Service). The series attempts to describe relationships between

human population growth and availability of natural resources in coastal areas. Planners and

managers, among others, should find this report and its data base useful for coastal

resource planning and management.

OBJECTIVES: (1) To compile and synthesize information from existing sources concerning

social, demographic, and economic factors in the Alabama coastal region.

DESCRIPTION: The socioeconomic study consists of a series of chapters containing

quantitative and qualitative descriptions of nine regional socioeconomic components.

Recommendations for planners and identification of data gaps are given in each chapter.

The chapters concern: (1) social and demographic characteristics; (2) industrial and

residential development; (3) agricultural and forestry production; (4) mineral production; (5)

commercial fishing; (6) transportation; (7) recreation/tourism; (8) multiple use conflicts; and

(9) environmental issues and regulations. All figures and tables are given in a data appendix

in the order that they appear in the text. Data were obtained from various published

documents. Except for evaluation and interpretation, the document is based entirely on

secondary sources.

SIGNIFICANT CONCLUSIONS: Coastal Alabama, similar to other coastal areas, has natural

resources that cause it to be attractive for recreation, residential, and industrial

development. Conflicts arise as development demands alteration to coastal ecosystems. As

demand for coastal resources increases, land use and resource planners are confronted with

greater challenges in attempts to maintain a proper balance among competing users.

STUDY RESULTS: Coastal Alabama is a fast growing area. Population in Mobile and

Baldwin Counties increased from 1 74,300 in 1 940 to 442,800 in 1980. Rapid growth is

expected to continue. Population at Mobile, the area's largest population center, currently

is about 200,500. Compared to many areas of the Nation, people of coastal Alabama are

less affluent and less educated. The coastal population characteristically contains a high

percentage of minorities (e.g., blacks). Recent trends indicate that the gap in income is

narrowing.

The basic regional industries or services are paper and allied products; shipbuilding and

repair; chemicals and allied products; construction; transportation; communication; utilities;

lumber and wood products; services; and wholesale and retail trade. The region's

employment increased from 131,600 in 1969 to 172,300 in 1978 and could reach 233,400

by 2000. Impetus for future economic expansion will be generated by the

Tennessee-Tombigbee Waterway, increased coal shipments through the Port of Mobile, and

Coastal Studies 101
expanded production, storage, and transportation of oil and gas. Regional land area is

7,484 km2 (2,890 mi2). In 1975, forested lands made up 48% of the total land; agriculture,

19%; transportation, communication, and utilities, 3%; residential, 2%; industrial and

commercial, 1 %; and undeveloped, 27%.

Although agriculture and forestry are dominant land uses in the region, income from these

sectors is relatively low. In 1 978, agriculture, directly and indirectly, generated about 11 %

of total employment and income, and forestry generated only 1 %. Principal agricultural

products are soybeans, vegetables, cattle, and nursery products. Major forestry products

are lumber and pulpwood.

Principal mineral industry products are oil, gas, sand, gravel, clay, and oyster shells. Oil and

gas production is economically most important, representing a relatively new but rapidly

growing regional industry. In 1 979, Alabama ranked 1 7th nationally in oil production and

20th in natural gas production. Recent natural gas discovery in Mobile Bay has increased

interest in bay, nearshore, and offshore exploration. In April 1980, the State leased 13

tracts in Mobile Bay, Mississippi Sound, and the Gulf of Mexico 3-mile offshore area; in the

near future, tracts in Federal OCS waters may be offered.

In 1978, 23 finfish species and 7 shellfish species were landed commercially in coastal

Alabama. Shrimp have consistently ranked first in volume and value since 1955, accounting

for 33 to 50% of total pounds landed and 80 to 85% of dockside value. Oyster ($1.2

million dockside in 1976) and crab ($281,000 dockside in 1976) fisheries are relatively

small. Atlantic croaker is the principal regional finfish species. Other commercial saltwater

species include spotted seatrout, southern flounder, and striped mullet. Commercial

freshwater fisheries exist for channel catfish, smallmouth buffalo, and freshwater drum.

Coastal Alabama is served by a well developed transportation system. Terminal facilities for

rail, highway, air, and water are centered in Mobile County. Water transportation centered

around Mobile Bay with a system of navigable waterways is dominant and has been the

primary contributor to the area's economic development since the 1 7th century. Mobile Bay

ranks 13th among the Nation's ports, handling mostly bulk commodities (coal, grain, and

iron ore). The Tennessee-Tombigbee Waterway, scheduled for completion in 1986, will link

the Tennessee and Ohio Rivers to the Tombigbee River and Port of Mobile. The Port of

Mobile and Mobile Harbor are undergoing expansion to accommodate expected increased

transport. lntercity highway transportation is served by 1-10 and 1-65. Rail service (freight

only) is provided by four railroads--Louisville and Nashville, Iflinois Central Gulf, St.

Louis-San Francisco (Frisco), and Southern. Commercial air transportation is available at

Bates Field and Brookley Field.

In 1 980, resident and tourist outdoor recreation in Mobile and Baldwin Counties was

expected to add up to over 51 million user days. Most of the user participation was near

the shore. An estimated 4.4 million tourists visited the two county area and spent $117.8

million. Sportfishing and hunting are major regional sports. The Mobile Delta is the principle

freshwater fishing area for largemouth bass, sunfish, crappies, channel catfish, and alligator

gar. Marine fishermen use all regional estuaries and bays, as well as Mississippi Sound and

Gulf waters. Principal sport species are amberjack, Spanish and king mackerel, southern

flounder, striped mullet, and spotted seatrout. Shrimping and crabbing also are major sport

1 02 Coastal Studies
activities. Hunting seasons begin in mid-September and continue to late April. Duck and

raccoon are hunted in the lower Delta. Whitetail deer, turkey, and small game are taken in

most areas of the region.

Many of the social and economic benefits prevalent in the region are dependent upon

natural resources. Competition for these resources causes multiple-use conflicts and

environmental stress. Although the conflicts generate some social, economic, and political

repercussions, the issues usually are environmental. Major environmental conflicts are

dredging, mining, petroleum extraction, construction, transportation, pollution, waste

disposal, farming, and logging. Recreation activities most likely to be affected by these

multiple uses are commercial fishing, sportfishing, hunting, recreational boating, swimming,

hiking, and camping.

Water pollution is a serious problem in and adjacent to Mobile Bay. Spoil disposal from port

and channel construction and maintenance has caused environmental concerns. Alteration

or destruction of marshes and shallow bay bottoms caused by port, commercial, residential,

and recreational development needs to be prevented. Principal point discharges are

municipal sewage treatment facilities, paper mills, and chemical plants. Nonpoint discharges

include urban storm water runoff and septic chainfields in low lying areas. Air pollution is

confined to Mobile County. A major environmental issue is natural habitat loss. Estuaries,

marshes, and barrier islands provide storm protection, waste assimilation, and recreation.

Threatened and endangered natural lands and waters and other areas of high ecological

value to man are the Mobile Delta, coastal barrier islands, submerged grassbeds, tidal

marshes, wet acid pinelands, mesic ravine woods, and habitats of endangered and

threatened species.

STUDY PRODUCT(S): Friend, J. H., M. Lyon, N. N. Garrett, J. L. Borom, J. Ferguson, and

G. C. Lloyd. 1982. Alabama Coastal Region Ecological Characterization. Vol. 3, A

Socioeconomic Study. A final report by the U.S. Fish and Wildlife Service for the U.S.

Department of the Interior, Minerals Management Service Gulf of Mexico OCS Office,

Metairie, LA. NTIS No. PB83-190017. FWS/OBS-81/41. Contract No.

14-12-0001-30037. 367 pp.

STUDY TITLE: Northeastern Gulf of Mexico Coastal Ecological Characterization.

COMPLETION DATE OF REPORT: October 1982.

CUMULATIVE PROJECT COST: $1,185,000.

KEY WORDS: Eastern Gulf; Central Gulf; Alabama; baseline; socioeconomics; population;

demographics; development; minerals; tourism; recreation; commercial fishing; recreational

fishing; agriculture; transportation; pollution; characterization; literature review; synthesis.

Coastal Studies 1 03
QVLP OP MtXIOO IOI0M ALABAMA COASTAL REGION OTUDY AREA (INCLUDE8 MOBILE AND BALDWIN COUUTIE8). o 25 50 

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REPORT TITLE: Florida Coastal Ecological Characterization: A Socioeconomic Study of the

Northwestern Region.

MMS PUBLICATION NUMBER: MMS 88-0063.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico.

BACKGROUND: The Florida Coastal Ecological Characterization: A Socioeconomic Study

of the Northwestern Region is one of a series of characterizations of coastal socioeconomic

systems produced and funded jointly by the Minerals Management Service and U.S. Fish and

Wildlife Service. The series describes the components and interrelationships among

complex processes that include population and demographic characteristics, mineral

production, multiple-use conflicts, recreation and tourism, agriculture production, sport and

commercial fishing, transportation, industrial and residential development, and

environmental issues and regulations. This report and data appendix should prove useful for

coastal planning and management.

OBJECTIVES: (1) To compile and synthesize information from existing sources about

social and economic characterizations of the northwestern coastal region of Florida.

DESCRIPTION: The study is a compilation and synthesis of information from existing

sources about the social and economic characteristics of the northwestern coastal region of

Florida, including Escambia, Santa Rosa, Okaloosa, Walton, Bay, Gulf, and Franklin

Counties. Individual authors have contributed sections in Volume I on the following topics:

(1) population and demographic characteristics; (2) transportation; (3) residential and

industrial development; (4) socioeconomic trends in agriculture; (5) mineraland oil

resources; (6) recreation and tourism; (7) commercial and sport fisheries; (8) multiple-use

conflicts; (9) environmental issues and regulations; and (10) energetics models of

socioeconomic systems. Volumes II and Ill comprise data appendices with tables and

figures from existing sources on the topics listed above.

SIGNIFICANT CONCLUSIONS: Offshore oil and gas development, deepwater ports,

processing and shipping of petroleum products, and other Outer Continental Shelf

(OCS)-related activities potentially have major environmental, economic, and social impacts

on northwestern Florida's coastal wetlands, natural resources, and communities. A major

environmental threat is the potential for spills during drilling or transportation activities. A

major oil spiii could be devastating because of the vulnerable coastal environment and the

regions heavy reliance on tourism. Intensive OCS exploration and development generates

considerable onshore activity which is accompanied by environmental, economic, and social

impacts that can be either beneficial or detrimental.

STUDY RESULTS: Northwestern Florida is rather sparsely populated and is more rural than

urban. Recent population increases are due to natural increases rather than to immigration.

The study area is economically weak. In 1970, about 20% of families were at the poverty

level and only 10% earned $15,000 or more. Median school years completed are lower

than for the State. Unemployment is higher than the State average. Northwestern Florida

lacks licensed professionals and adequate medical facilities for its area and population.

Coastal Studies 1 07
Transportation systems that were reviewed included seaports, airports, railroads, highways,

bus systems, and pipelines. Three major (Pensacola, Panama City, and Port

St. Joe) and two minor (Apalachicola and Carabelle) seaports exist in the study area. The

region contains three commercial and nine small public airports. Four freight line railroads

serve northwestern Florida. Within the study region, Interstate Highway 10 (1-10) is the

major east-west highway facility. The seven counties in the region are served by Greyhound

and Trailways intercity bus routes. Major regional pipelines are privately owned and serve

primarily to transport natural gas.

Rapid development is taking place along some coastal areas of the region. Increase in

housing units, primarily single family homes, in 1970-1980 doubled that of 1960-1970.

The region is not heavily industrialized. The amount of land suitable for development near

urbanized areas is limited because of extensive wetlands, large public holdings, and because

of hurricane surge hazards or riverine flooding. Population growth and industrial

development are partially restricted by availability and capacity of public utilities.

Agriculture and forestry are among the major industries in the region. Northwestern Florida

is a major producer of field corn, soybeans, wheat, peanuts, cotton, poultry, and forest

products. Forestry accounts for the major share of land and income.

Regional mineral production has increased substantially during the past few years because

of oil fields near Jay. Oil and gas produce greater revenue in the region than all other

minerals combined, and they now account for about one-third of the value of all mineral

production in the State. Significant amounts of oil and gas were not found offshore. There

is expectation of a nearshore gas find in East Bay, but exploration may not begin for years.

Nonfuel mineral production includes sand and gravel, ilmenite and rutile from coastal sands,

and magnesia from sea water.

Tourism in northwestern Florida has increased sharply since the mid-1960s. Numbers of

tourists in 1965-1979 increased nearly 300%. In 1980, public lands contributed more

recreation areas (1.63 million acres) than the private sector (8,745 acres) and more beach

frontage (423,750 ft compared to 4,030 ft). Data on freshwater sportfishing can be related

by licenses issued. Intensity of saltwater sportfishing can only be estimated.

The regional offshore and estuarine waters support extensive sport and commercial

fisheries. Catch and value figures for commercial landings are available. Commercial catch

includes finfish (snappers and groupers, mackerels, spotted seatrout, striped mullet, and

ladyfish) and shellfish (shrimp, blue crabs, oysters, and bay and calico scallops).

Coastal waters and estuaries of the region have been seriously altered by industrial,

residential, and commercial developments, partly because of lack of consideration for the

integrity of the natural environment. Development of institutional procedures for responding

to failures of the market system to consider environmental planning is a difficult task.

Trade-offs between economy and environment depend upon society's evaluation of need for

maintaining viable coastal ecosystems as opposed to further residential, commercial, and

industrial developments. Areas selected for discussion--Apalachicola River, St. George

Island, Panama City Beaches, East Bay, and Escambia Bay--are areas of special concern

having felt effects of various types of expanding onshore development. Actions have

resulted because of the relatively high abundance of environmental data available about

1 08 Coastal Studies
these areas. Environmental research in all regional coastal waters must be expanded to

demonstrate environmental values in multiple-use conflicts.

The quality of the ambient air in the region is considered to be good due to scarcity of

heavy industry. The study area is an area of great hydrological activity, including dredging,

diking, and draining. These alterations result in habitat stress, dune destruction, reduced

flow of detrital food sources for aquatic life, decreased dissolved oxygen, increased coliform

counts, reduced runoff through natural systems, and increased erosion. Groundwater is

seriously depleted in certain areas of the region such as Ft. Walton Beach, but generally the

region is rich in quantity and quality of groundwater.

The regional socioeconomic systems are modeled using energy as a common denominator

for all flows and storages within the system. Energy circuit models are evaluated by

measuring energy quantity flowing in a particular pathway or stored in the system. Because

all activities, interactions, and even storages require or represent energy, it is possible and

practical to quantify a particular pathway by its energy value.

STUDY PRODUCT(S): French, C. 0. and J. W. Parsons (eds.). 1983. Florida Coastal

Ecological Characterization: A Socioeconomic Study of the Northwestern Region. Vol. I,

Text. A final report by the U.S. Fish and Wildlife Service for the U.S. Department of the

Interior, Minerals Management Service Gulf of Mexico OCS Office, Metairie, LA. NTIS

No. PB84-174200. FWS/OBS-83/15. Contract No. 14-12-0001-30037. 306 pp.

French, C. 0. and J. W. Parsons (eds.). 1983. Florida Coastal Ecological Characterization:

A Socioeconomic Study of the Northwestern Region. Data Appendices. A final report by

the U.S. Fish and Wildlife Service for the U.S. Department of the Interior, Minerals

Management Service Gulf of Mexico OCS Office, Metairie, LA. Vol. II (Data Appendix,

Part 1, 309 pp.)-NTIS No. PB84-174218; Vol. III (Data Appendix, Part 2, 375 pp.)-NTIS No.

PB84-1 74192. FWS/OBS-83/1 5. Contract No. 14-12-0001-30037.

STUDY TITLE: Northeastern Gulf of Mexico Coastal Ecological Characterization.

COMPLETION DATE OF REPORT: August 1983.

CUMULATIVE PROJECT COST: 1,185,000.

KEY WORDS: Eastern Gulf; Florida; baseline; socioeconomics; characterization; coastal

zone; synthesis; population; demographics; development; minerals; tourism; recreation;

commercial fishing; recreational fishing; transportation; pollution; agriculture; modeling;

literature review.

Coastal Studies 109
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I I 8TUDY AREA FOR THE FLORIDA COASTAL ECOLOGICAL CHARACTERIZATION: A SOCIOECONOMIC

STUDY OF THE NORTHWESTERN REGION.

PORT MTh
REPORT TITLE: The Ecology of Irregularly Flooded Salt Marshes of the Northeastern Gulf

of Mexico: A Community Profile.

MMS PUBLICATION NUMBER: Contract No. 14-12-0001-30037.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico.

BACKGROUND: Marsh areas dominated by Juncus roemerianus (black needlerush) occur

along Atlantic and Gulf of Mexico coasts of North America between 25°N and 40°N Lat. J.

roemerianus-dominated marshes comprise over 50% of the marshland present along the

northeastern Gulf (western Florida, Alabama, and Mississippi). These marshes provide food

and nutrient sources, faunal habitat, water purification systems, and shoreline stabilization.

Wide distribution and close proximity to open water of J. roemerianus- dominated marshes

makes them highly susceptible to man-induced impacts (e.g., oil spills). Large information

gaps are present concerning many aspects of marsh habitats. To help understand and build

awareness of marshland importance, information concerning the role and interrelationships

of this habitat with natural and man-induced factors is vital.

OBJECTIVES: (1) To describe J. roemerianus-dominated marsh systems and the biological

and ecological components within the systems; and (2) To evaluate the marsh systems and

various impacts.

DESCRIPTION: The report concerns irregularly flooded J. roemerianus marshes along

shores of the northeastern Gulf of Mexico from the Pearl River, Mississippi to Cedar Key,

Florida. The marsh community profile provides "state-of-the- knowledge" synthesis of

information and literature of this community. The profile includes information concerning

structural and functional community aspects; its environmental setting, zonation, vascular

and non-vascular plant communities, marsh fauna, ecology, and human impact.

SIGNIFICANT CONCLUSIONS: Presentation of existing data related to the marsh

community emphasizes the paucity of information concerning various aspects of marsh

ecology. Significant data gaps concern: overall biotic concepts (i.e., community dynamics),

marsh hydrology, nutrient contributions, mitigation options, and impact studies. These large

data gaps that exist are of special concern when considering J. roemerianus- dominated

marshes. This is due in part to research emphasis being placed on marsh community

structure and function dominated by species other than J. roemerianus (e.g., Spartina

alterniflora).

Data confirm the relatively high primary productivity of marsh communities; however,

productivity is probably underestimated because no data are available concerning the algal

productivity component. Marshes are also ecologically important as a base for detrital food

chains. Pollutants (e.g., oil spills) have the potential to alter community structure and affect

aspects of ecological importance. Marshes must be protected because of their unique and

critical role amongst coastal ecosystems. Mitigation options are limited, therefore, marsh

preservation and restoration, where possible, is imperative.

STUDY RESULTS: J. roemerianus-dominated marsh distribution and development are

dictated by a number of physical parameters (e.g., substrate conditions) that occur along

Coastal Studies 111
the northeastern Gulf of Mexico. These variable physical parameters account for relatively

low species diversity among marsh plant communities. Few plant species are adapted to

the high stress conditions that exist in marsh environments.

A general zonation pattern applies to the J. roemerianus-dominated marsh. A S. a/tern/flora

zone borders open water within the intertidal area. Moving landward, J. roemerianus

becomes dominant. The Juncus zone is the largest and comprises the bulk of marsh

biomass. Inside the Juncus zone, salt flats prevail where hypersalinity causes colonization

of sparse halophytic plants. The most landward zone, called the high meadow, is not

normally susceptible to strong tidal fluxes and, therefore, has a plant community of

relatively high species diversity.

Marsh substrates provide for epiphytic microfloral communities. Blue-green benthic algae

have low species diversity. Blue-green algal distributions are determined by light intensity,

therefore, habitat alteration that affects marsh canopy may impact community structure by

altering algal composition. Little information is available concerning marsh non-vascular

plants.

Eighty-eight species of macroinvertebrates (excluding insects and oligochaetes) are reported

from northeastern Gulf of Mexico marshes. Macroinvertebrates show marked seasonal

fluctuations due to plankton recruitment. Larval decapods dominate meroplankton and, as

adults, are critical to detrital energy flow.

Fish populations are highly diverse and abundant due to availability of numerous habitats.

Temporal population changes are related to breeding patterns of fish that utilize the marsh

as nurseries. Marsh fish have little commercial importance, however, by functioning in

energy transfer to other habitats, they indirectly affect commercial species.

Marsh avifauna are diverse (125 resident species). Large seasonal population changes are

due to influxes of migratory species. Birds occupy high trophic levels within the marsh

ecosystem and are very important in nutrient cycling.

Marshes are highly productive and have high nutrient turnover rates. Ecological linkages

between marshes and adjacent habitats are obvious, however, data are unavailable to

indicate mechanisms and pathways.

Man-induced impacts on marsh habitats include: alteration, destruction, petroleum pollution,

effluents, and mitigation. Oil pollution impacts can be acute and of long duration.

Mitigation options consist of replanting and fertilization of existing marshes, and

establishment of new marshes by planting on dredge material disposal sites.

STUDY PRODUCT(S): Stout, J. P. 1984. The Ecology of Irregularly Flooded Salt Marshes

of the Northeastern Gulf of Mexico: A Community Profile. A final report by the U.S. Fish

and Wildlife Service for the U.S. Department of the. Interior, Minerals Management Service

Gulf of Mexico OCS Region, Metairie, LA. FWS Report 85(7.1). Contract No.

14-12-0001-30037. 98 pp.

STUDY TITLE: Northeastern Gulf of Mexico Coastal Ecological Characterization.

11 2 Coastal Studies
COMPLETION DATE OF REPORT: December 1984.

CUMULATIVE PROJECT COST: $1,185,000.

KEY WORDS: Eastern Gulf; Central Gulf; baseline; biology; characterization; community;

salt marsh; needlerush; Juncus; Mississippi; Florida; Alabama; floral zones; macrofauna; fish;

birds; impacts.

Coastal Studies 11 3
MORGAN CITY KEY MAP 

CENT IA I. OUt.? OF MEXICO COION STUDY AREA OF JUNCUS ROEMERIANUS MARSHES IN THE NORTHEASTERN OULF OF MEXICO. o so 60 _l 

0 55 50 76 00 KIL
REPORT TITLE: Northwestern Florida Ecological Characterization: An Ecological Atlas.

MMS PUBLICATION NUMBER: MMS 85-001 1.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico.

BACKGROUND: The Northwestern Florida Ecological Characterization study is one of a

series of characterizations of coastal ecosystems being produced by the U.S. Fish and

Wildlife Service (USFWS). Funding was provided by the USFWS and the Minerals

Management Service. Federal and State decisionmakers, among others, may use these

maps and narratives for coastal planning and management, and in planning for Outer

Continental Shelf oil and gas development.

OBJECTIVES: (1) To compile existing information about the biological, social, and physical

sciences for the Gulf of Mexico coastal counties of Florida from Escambia County to

Hernando County.

DESCRIPTION: The study area is the northeastern Gulf of Mexico coastal region of Florida

from the western boundary of Escambia County and southeast to the Hernando-Pasco

County line. The offshore area includes the region from the State-Federal demarcation to

the shoreline. The inland area includes Escambia, Santa Rosa, Okaloosa, Walton,

Washington, Bay, Calhoon, Gulf, Franklin, Wakulla, Jefferson, Taylor, Dixie, Levy, Citrus,

and Hernando Counties. The products of the atlas include 18 U.S. Geological Survey maps

with the topic information in overlays, producing 90 maps and a map narrative. The

information in the atlas is previously existing data on biological resources; socioeconomic

features; soils and Iandforms; and oil, gas, and mineral resources.

SIGNIFICANT CONCLUSIONS: The northwestern Florida study area is located in the Outer

Continental Shelf Plain Forest Ecological Province, characterized by gentle slopes and

numerous sluggish rivers and creeks. Swamps, marshes, and lakes are abundant and

support a wide variety of animal life.

STUDY RESULTS: Five habitat types are depicted on the biological resources maps and

described in the narrative: estuarine tidal marshes, estuarine scrub/shrub (mangrove forest),

palustrine freshwater marshes, palustrine forests, and seagrass beds. Tidal marshes are

dominated by black needlerush and smooth cordgrass. Mangrove forests are composed of

red, black, and white mangroves. Palustrine freshwater marshes include all nontidal

wetlands dominated by persistent emergents and all such wetlands that occur in tidal areas

where salinity is below 0.5 ppt. Dominant vegetation includes sawgrass, cattail, bulltongue,

spikerush, or maidencane. Palustrine forests include all nontidal and low salinity (less than

0.5 ppt) wetlands dominated by trees such as cypress, bay, elm, willow, ash, oak, tupelo,

and maple. Seagrass beds are dominated by six seagrass species; turtle grass, manatee

grass, shoal grass, widgeon grass, and two Ha/ophila species.

Other habitats and plant assemblages indicated on the maps and described in the narrative

include existing artificial reefs; oyster beds; finfish spawning nursery, and harvest areas;

sensitive plant species; colonial bird nesting sites; and threatened and endangered animals.

Shellfish harvest areas include oyster beds, scallop beds, clams, shrimp, and blue crab.

Coastal Studies 11 5
Finfish spawning, nursery, and harvest areas include estuarine dependent, reef, and coastal

pelagic fishes and commercial fisheries. Sensitive plant species include those listed (or

under review) as threatened or endangered by the USFWS and the Florida Committee on

Rare and Endangered Plants and Animals. Colonial bird nesting sites include nesting sites

for seabirds, shorebirds, wading birds, and migratory waterfowl. Threatened and

endangered animals include those listed (or under review) by the USFWS and Florida Game

and Freshwater Fish Commission.

Within the northwestern Florida region, Citrus and Hernando Counties are rapidly growing

retirement areas while the remaining counties are predominantly rural. The described and

mapped socioeconomic features include National lands (Natural wilderness areas, National

wildlife refuges, National marine and estuarine sanctuaries, military lands, and National

seashores); State lands (State parks, recreation areas, wilderness areas, wildlife

management areas, aquatic preserves, and conservation lands), recreation lands, intensively

utilized recreational beach access points, marinas, charter and head boat locations, public

boat ramps, Florida canoe trail systems, major public fishing piers, artificial reefs,

shipwrecks, major offshore structures, land use, landfills, dredge spoil disposal sites,

industrial and municipal point source discharges, national natural landmarks, historic places

designated on the national register, archeological and historic sites, and Nature Conservancy

lands.

Study area soils are described and mapped according to the U.S. Soil and Conservation

Service classification reflecting patterns of soil associations. Associations include one or

more major soil and at least one minor soil. Study area soils are derived from recent beach

deposits, river alluvium, marine terrace deposits, or directly from a particular geologic

formation.

The study area has been divided into two major physiographic zones; central or

mid-peninsular zone, and northern or proximal zone. The former is characterized by

discontinuous highlands as sub-parallel ridges separated by broad valleys; the latter, a broad

upland extending westward into panhandle region highlands. The northern zone is divided

into two major physiographic regions--Gulf Coastal Lowlands and Northern Highlands--and

several physiographic provinces--Western Highlands, Escambia Valley, Gulf Coastal

Lowlands, Gulf Barrier Chain, Marianna Lowlands, New Hope Ridge, Greenhead Slope,

Fountain Slope, Grand Ridge, and Northern Highlands. Current data on beach erosion,

existing active dunes, and faults are described and depicted in the study products with soils

and landforms.

Florida is the sixth largest non-fuel producing state in the nation. In dollars, phosphate is

the leading mineral source, followed by petroleum, cement, and stone. In the study area, oil

and gas, sand and gravel, clay, limestone, dolomite, peat, and shell deposits are leading

mineral resources. Quantity and location of surface mineral resources, oil and gas pipelines,

and drilling sites are described and depicted in the study products.

The study area climate is warm subtropical and includes a summer and winter rainy season.

The rainy seasons cause fluctuations in the area surface water hydrology and to some

extent groundwater. The Floridan Aquifer is the important groundwater feature in the study

area. The study products provide potentiometric contour maps of the aquifer. Surface

11 6 Coastal Studies
wind patterns for the three primary wind seasons--fall/summer, spring, and summer--and

annual wind roses are provided in the products. There exists a lack of reliable current data

in the study area. Available current data are plotted as current roses on the atlas maps.

Florida is the most vulnerable State in the U.S. to hurricanes during the season from June

through November. Atlas maps depict maximum area subject to flooding for Saffir/Simpson

category 1-5 hurricanes. The hydrologic unit water budget, the storage capacity of each

hydrologic unit, is calculated using available data. Data are provided and depicted on the

maps from U.S. Geological Survey stream gauging station including water stage, specific

conductivity, and chloride levels. Estimated water use by primary users--agriculture,

municipal water supply systems, and industry--is estimated by county.

STUDY PRODUCT(S): Palik, T. F. and J. T. Kunneke. 1984. Northwestern Florida

Ecological Characterization: An Ecological Atlas. Map Narratives. A final report by the U.S.

Fish and Wildlife Service for the U.S. Department of the Interior, Minerals Management

Service Gulf of Mexico OCS Region, Metairie, LA. FWS/OBS-82/47.1. Contract No.

14-12-0001-30037. 302 pp.

Palik, T. F. and J. T. Kunneke. 1984. Northwestern Florida Ecological Characterization: An

Ecological Atlas. A map series by the U.S. Fish and Wildlife Service for the U.S.

Department of the Interior, Minerals Management Service Gulf of Mexico OCS Region,

Metairie, LA. FWS/OBS-82/47.1. Contract No. 14-12-0001-30037. 90 maps (1:100,000):

Al through E18.

STUDY TITLE: Northeastern Gulf of Mexico Coastal Ecological Characterization.

COMPLETION DATE OF REPORT: September 1 984.

CUMULATIVE PROJECT COST: $1,185,000.

KEY WORDS: Eastern Gulf; Florida; baseline; biology; characterization; terrestrial; habitat;

estuarine; freshwater; marine; seagrasses; mangroves; birds; endangered species;

commercial fishing; socioeconomics; recreation; recreational fishing; soil; minerals;

hydrology; maps; narratives; literature review; synthesis.

Coastal Studies 11 7
- 30

- 29

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-

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GULF OF EXIC0 REGION

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ACCESS NUMBER:300375

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I I STUDY AREA FOR THE NORTHEASTERN GULF OF MEXICO COASTAL ECOLOGICAL CHARACTERIZATION.

St.

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24 2000.,.
REPORT TITLE: Ecological Characterization Atlas of Coastal Alabama: Map Narrative.

MMS PUBLICATION NUMBER: MMS 84-0052.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico.

BACKGROUND: The Ecological Characterization Atlas of Coastal Alabama is one of a

series of characterizations of coastal ecosystems cosponsored by the Minerals Management

Service and produced by the U.S. Fish and Wildlife Service to provide coastal planning and

management personnel with information relative to coastal ecology.

OBJECTIVES: (1) To provide a compilation of existing information concerning the

biological, physical, and coastal conditions in Mobile and Baldwin Counties, Alabama.

DESCRIPTION: The study area includes the region from the State-Federal demarcation line

to the shoreline, and the inland area of Mobile and Baldwin Counties. The atlas consists of

composite overlay information provided on six 1:100,000-scale base maps with five main

subject maps, totaling thirty maps. A narrative accompanying the maps discusses the

mapped topics. Atlas topics include biological resources; socioeconomic features; soils and

landforms; oil, gas, and mineral resources; and hydrology and climatology.

SIGNIFICANT CONCLUSIONS: Total wetland acreage in the study area is 692,000 acres,

or 38% of the area, and is dominated by palustrine forest and scrub/shrub. Topics

discussed and mapped in the biological resources section include bird nesting sites,

submerged aquatic vegetation, shellfish harvesting areas, and recreational and commercial

finfish. Topics discussed and mapped in the socioeconomic section include man-made and

natural areas having ecological or economic significance. Topics discussed and mapped in

the soils and landforms section include regional surface landforms, soils, beach erosion and

accretion, faults, high-energy beaches, and active dunes'. Past and existing oil, gas, and

minerals mining activities are discussed and mapped in that section. Information on

availability and use of water is provided in the climatology and hydrology section.

STUDY RESULTS: Wetland habitats are essential nesting, breeding, rearing, nursery, and

feeding grounds for many species of fish, birds, and other wildlife in coastal Alabama.

Three wetland categories are mapped and described in the atlas; estuarine intertidal

emergent wetlands, palustrine emergent wetlands, and combined palustrine forested and

scrub-shrub wetlands. In the study area, total wetland acreage was calculated to be

692,000 acres, or about 38% of the two counties. Palustrine forest and scrub-shrub is

dominant, occupying 621,000 acres or 34% of the area. Nesting sites for seabirds and

wading birds, shorebirds, and migratory waterfowl are located on the atlas maps. The most

important wading bird nesting site is Cat Island. The Point Aux Chenes-Grand Bay Swamp

and Lower Mobile Bay are important wintering locations for migratory waterfowl.

Submerged aquatic vegetation occurs within the study area and is indicated on the atlas

maps. Tape grass is a freshwater species. Widgeongrass, shoalgrass, and turtlegrass are

estuarine species. Shellfish harvest areas indicated on the atlas maps include shrimping

areas, blue crab harvesting areas, and oyster reefs. Recreational and commercial finfish

include Florida pompano, mackerels, Gulf menhaden, southern flounder, croaker, groupers,

Coastal Studies 11 9
snappers, mullets, red drum, sardines, and sea trout. Study area endangered and

threatened species are not mapped but listed in the atlas narrative.

Socioeconomic elements mapped and discussed include man-made features and natural

areas having either ecological or economic significance, such as wildlife refuges, State park

recreational areas, barrier islands, and historical or archeological sites. Man-made features

include solid waste landfills, navigation channels, and dredge-spoil disposal areas. Four land

use categories are mapped; forested, urban, agricultural, and uncategorized (mostly

wetlands). Other mapped and discussed socioeconomic features include intensively used

recreational beaches; charter and head boat services; permitted artificial fishing; public piers;

public access areas and marinas; barrier islands and spits; point source discharges; solid

waste landfills and onshore disposal sites; man-made land; historic places; archeological

sites; navigation channels; dredge spoil disposal areas; and offshore obstrUctions and

structures.

The soil and landforms atlas topic deals with regional surface landforms, soils, beach erosion

and accretion areas, faults, high-energy beaches, and active dunes. The basic soil unit in

the atlas is soil associations, a group of soil series found in the same geographic area. The

study area is located in the lower Coastal Plain of the Gulf Coastal Plain physiographic

province. Offshore, coastal waters belong to the Mississippi-Alabama Shelf Section of the

Continental Shelf physiographic province. The lower Coastal Plain is subdivided into the

Southern Pine Hills and Coastal Lowlands. The lowlands include both alluvial and deltaic

plains. Coastal areas experiencing critical and non-critical erosion are mapped and described

in the atlas. Faults shown on the atlas maps are marked as to their upthrown and

downthrown sides. Several faults exist in the area, but probability of damage from an

earthquake is unlikely. Active dunes are sand landforms influenced by wave action and/or

aeolian (wind) processes that are in a constant state of change. Active dunes areas are

delineated on the maps.

The oil, gas, and mineral section provides information on these activities in coastal Alabama

including pipeline routes, refineries, and drilling sites. Significant mineral deposits (e.g., clay

and gravel) are located and discussed.

The climatology and hydrology section relates information on water availability and use in

the study area. Climate is primarily humid subtropical, due to the warming influence of the

Gulf of Mexico. Normal annual rainfall for the study area is the States highest and among

the highest in the U.S., averaging 162.5 cm (64 in). Prevailing surface winds are southerly

for March through July, easterly for August and September, and northerly for remaining

months. Annual wind roses are given on the maps. Coastal Alabama is susceptible to

hurricanes; information on the probability of hurricanes striking the area and past hurricane

damage is discussed in the atlas. Hydrologic units are geographic areas representing part or

all of a surface drainage basin or distinct hydrologic feature delineated by the

U.S. Geological Survey (USGS). Stream flow of each unit is measured at USGS gauging

stations (indicated on maps). Summaries of flows are in the atlas. Surface water quality is

measured at these stations and data are summarized in the atlas. Quantities of high quality

groundwater are available in the study area. Groundwater quantity and quality are

summarized from USGS wells (indicated on maps) in the atlas. Currents and circulation

patterns along the Alabama coast are influenced by tides, freshwater discharges, shoreline

1 20 Coastal Studies
configurations, winds, longshore currents, and the Coriolis effect. Currents within Mobile

Bay and Mississippi Sound and coastal areas are summarized in the atlas.

STUDY PRODUCT(S): Smith, M. F., Jr. (ed.). 1984. Ecological Characterization Atlas of

Coastal Alabama: Map Narrative. A final report by the U.S. Fish and Wildlife Service for the

U.S. Department of the Interior, Minerals Management Service Gulf of Mexico OCS Region,

Metairie, LA. NTIS No. PB85-247492. FWS/OBS-82/46. MMS Report 84-0052. Contract

No. 14-12-0001-30037. 189 pp. + 30 maps (1:100,000).

STUDY TITLE: Northeastern Gulf of Mexico Coastal Ecological Characterization.

COMPLETION DATE OF REPORT: August 1 984.

CUMULATIVE PROJECT COST: $1,185,000.

KEY WORDS: Eastern Gulf; Central Gulf; Alabama; baseline; biology; characterization;

terrestrial; habitat; socioeconomics; recreation; tourism; commercial fishing; recreational

fishing; soil; minerals; birds; hydrology; wetlands; endangered species; maps; narratives;

literature review; synthesis.

Coasta' Studies 121
OUI.P OP M131C0 l*aION *AITtPIN 0 33 30 73 100 

0 00 30 

STUDY AREA FOR THE ECOLOGICAL CHARACTERIZATION ATLAS OF COASTAL ALABAMA (INCLUDES MOBILE AND BALD
LIVING MARINE RESOURCES

The OCS oil and gas operations have the potential to affect certain endangered and

marine mammal species and their habitats in the coastal zone and offshore areas. Oil

spills and construction activities are the two principal impacting agents; however, other

impacts are also possible (for example, noise and other disturbances, aircraft and

vessel traffic, etc.). The objectives of the endangered species studies are (1) to obtain

an adequate database describing the locations, activities, and statuses of individual

endangered species and (2) to determine the potential effects of OCS oil and gas

operations on endangered and vulnerable marine mammals, birds, and turtles in the

Gulf of Mexico. The logical procedure to determine potential effects is two-tiered:

first, study the distribution, migratory patterns, habitats, and critical time periods for

these species to determine if/when conflicts or impacts occur; then, study specific

species and impact agents to establish mitigation measures.

Living Marine Resources 1 23
REPORT TITLE: A Review of the Ecology, Behavior, and Life History of the Bottlenose

Dolphin.

MMS PUBLICATION NUMBER: Contract No. 14-12-0001-29118.

APPLICABLE PLANNING AREA(S): South Atlantic; Straits of Florida; Eastern Gulf of

Mexico; Central Gulf of Mexico; Western Gulf of Mexico.

BACKGROUND: The bottlenose dolphin, Tursiops truncatus, is perhaps the marine

mammal species most likely to be affected by oil and gas exploration and production in the

Gulf of Mexico. Despite the fact that this species is relatively well known among the

Cetacea, serious gaps remain in our understanding of the animal and our ability to predict

the effects of oil and gas development.

OBJECTIVES: (1) To assess our current level of knowledge concerning Tursiops truncatus

in order to guide future avenues of research.

DESCRIPTION: Existing literature was reviewed to discuss the behavior, social

organization, movement patterns, and ecology of bottlenose dolphin. Based on the available

data, discussions were presented concerning the potential impacts from oil and gas

development. The applicability and usefulness of research techniques was also determined

from the available data.

SIGNIFICANT CONCLUSIONS: In spite of the availability of a large volume of information

on the ecology, behavior, and physiology of the bottlenose dolphin, it is not yet possible to

predict the potential impacts of offshore oil and gas development. It is suggested from the

data that oil exploration and drilling could have effects ranging from positive to neutral to

adverse. This uncertainty is largely due to a lack of baseline data on populations likely to be

affected by the oil and gas operations.

STUDY RESULTS: There is a need to determine the discreetness of bottlenose dolphin

stocks through consideration of behavior, morphology, and biochemical genetic factors.

This need is due to the fact that impacts from oil and gas development would be much

different on a small, local, discrete population than it would be on a large population over a

wide area.

Bottlenose dolphins appear to have quite complex patterns of social organization. Relatively

permanent social units that are closely tied to definable home ranges seem to be formed in

at least some portions of the species range. Within populations, social associations and

individual movements are based on the age and sex of the individuals. Displacement of

dolphins from particular portions of their ranges could affect social structure and population

recruitment. Learning within the context of the social unit is also critical.

Group size for dolphins varies according to the physiography of an area and the activity of

the group. Group size can change frequently during the course of the day as well as

seasonally. Group size increases with water depth or openness of the habitat and is

possibly related to foraging techniques and protection from predation.

Living Marine Resources 1 25
Potential impacts that should be avoided include disturbance of feeding, reproduction, and

other types of behavior; displacement from critical habitat; disruption of food resources; and

physical damage such as auditory injury and effects from direct contact with oil.

Some generalizations exist concerning the behavior of bottlenose dolphin. Dolphins appear

to be active both day and night. Feeding peaks have been noted in early morning and late

afternoon. Time devoted to feeding increases in fall and winter. Feeding strategies are

flexible and adapted to habitat and food available. Social behavior is a major component of

the daily regime.

Short-term and long-term movements appear to be related to food availability, protection

from predators, reproduction, and thermoregulation. The overriding theme in these

movements is variability. At least some coastal bottlenose dolphins maintain home ranges

which can include individual and herd as well as permanent and seasonal ranges. The social

mechanisms which exist between dolphin populations to maintain home range boundaries

are not known. Animals could be severely affected if they are forced from an area which is

familiar to them and which supplies their needs.

Due to the confused state of Tursiops taxonomy, it is difficult to determine normal

reproduction and growth patterns. This information is of utmost importance in assessing

the potential impacts of oil and gas development on dolphin populations. Reproduction

occurs in spring to early summer in the Gulf of Mexico with a secondary peak in October to

November in southern Florida. The number of years of reproductive activity is unknown.

Males mature at about 10 years and females at 5 years. Gestation is 11 to 12 months with

a single calf born every 2 to 3 years. Both sexes live about 25 years.

If dolphins use particular regions within their ranges for protection from predators, then loss

of these areas could be detrimental. In areas where large group size is critical for protection

from predation, activities which disrupt group behavior could also decrease survival rates.

Additionally, activities which introduce disabilities through water pollution or acoustic

activities could also increase susceptibility to predation.

Human-dolphin interactions result from boats, capture, fisheries activities, direct contact,

and from habitat alteration.

Existing data suggest that short-term exposure to oil may have minimal effects. Chronic oil

ingestion and chronic exposure to noise may pose potentially greater threats. Field

observations contradict laboratory findings that dolphins will avoid oil spills.

Dolphins may prove to be a good indicator species for assessing potential impacts on other

marine mammals less amenable to study. However, due to the bottlenose dolphin's

adaptability and flexibility, they may be less affected by potential disturbance than other

more specialized cetaceans. In order to assess impacts from oil and gas development,

research projects should be designed to study behavior in areas of established petroleum

activities, planned activities, and unaffected areas. Comparisons should be made in each

area of respiration rates, times at and below the surface, and time spent in basic behaviors

such as traveling, feeding, resting, and socializing. Also needed are observations on shifts

in group size, group composition movement patterns, and home range use. The most

1 26 Living Marine Resources
profitable study technique will involve long-term monitoring of behavior and social patterns

using photographic recognition, capture, tagging, and radio tracking.

STUDY PRODUCT(S): Shane, S. H., R. S. Wells, B. Würsig, and D. K. OdelI. 1982. A

Review of the Ecology, Behavior, and Life History of the Bottlenose Dolphin. A final report

by the U.S. Fish and Wildlife Service for the U.S. Department of the Interior, Minerals

Management Service Gulf of Mexico OCS Office, Metairie, LA. NTIS No. PB84-117613.

MMS-GM-PT-83-011. Contract No. 14-12-0001-29118. 72 pp.

STUDY TITLE: Distribution and Abundance of Endangered and Vulnerable Mammals, Birds,

and Turtles.

COMPLETION DATE OF REPORT: November 1982.

CUMULATIVE PROJECT COST: $100,000.

KEY WORDS: South Atlantic; Straits of Florida; Eastern Gulf; Central Gulf; Western Gulf;

endangered species; bottlenose dolphin; Tursiops; literature review; behavior; life history;

range; population; oil spill; industrial sound; impacts.

Map #29118 Unavailable.

Living Marine Resources i 27
REPORT TITLE: Proceedings of a Workshop on Cetaceans and Sea Turtles in the Gulf of

Mexico: Study Planning for Effects of Outer Continental Shelf Development.

MMS PUBLICATION NUMBER: Contract No. 14-12-0001-29118.

APPLICABLE PLANNING AREA(S): South Atlantic; Straits of Florida; Eastern Gulf of

Mexico; Central Gulf of Mexico; Western Gulf of Mexico.

BACKGROUND: Several Federal agencies, including the Bureau of Land Management (now

the Minerals Management Service) and the U.S. Fish and Wildlife service, have, historically,

expressed concern that adequate information be available to address the effects of offshore

oil and gas development on endangered and protected vertebrates. As a means of

establishing the current state of knowledge regarding individual species and their

susceptibility to development-related impacts, and to solicit research recommend-ations, a

workshop was conducted involving scientists knowledgeable about cetaceans, sea turtles,

and various physical and biological aspects of the Gulf of Mexico region.

OBJECTIVES: (1) To identify ways in which cetaceans and sea turtles have been or could

be affected, either directly or indirectly, by activities and events associated with offshore oil

and gas development; (2) to identify the types and specificity of data needed to predict,

detect, and mitigate possible adverse effects; (3) to identify and discuss the advantages and

disadvantages of various methods that might be used to obtain needed data; and (4) to

identify specific research and monitoring programs that would be required to obtain needed

data, including the necessary expertise, level of effort, equipment, and

facilities.

DESCRIPTION: A workshop was conducted during 6-8 April 1982 at the University of

Southern Mississippi. A total of 49 representatives from government, academia, and private

industry participated in the workshop. Working groups were convened on cetaceans and

sea turtles. Discussion sessions were summarized by the chairperson and reviewed by

participants.

SIGNIFICANT CONCLUSIONS: Information on the occurrence, distribution, behavior, and

ecology of cetacean and marine turtles in the Gulf of Mexico is generally lacking. These

species can be affected by oil and gas development in various ways, including mortality

from contact with or ingestion of oil, disruption of behavioral patterns from noise associated

with OCS activities, and fouling of nesting and feeding habitats, among others. Various

opportunities currently exist to use existing facilities to conduct qualitative surveys of

cetacean populations in the Gulf of Mexico. Additional information can be obtained from

radio tagging and tracking studies to obtain data on the movements of these species. An

important data gap exists relative to the early life history of sea turtles. To address these

needs, a series of studies were recommended to: collect data on the effects of oil on the

early life stages of turtles and their habitats; and compile biological information for turtle

species found off Florida and in the northeast Gulf of Mexico.

STUDY RESULTS: The Gulf of Mexico is influenced by Mississippi River discharges in the

north and by high salinity water from the Caribbean Sea in the southwest. Soft bottom

communities predominate within the Gulf of Mexico, where as pelagic communities are little

Living Marine Resources 1 29
known and have few commercially valuable species. While direct effects from oil and gas

development are spatially limited, effects over time are less well known. A key problem lies

in separating man-induced changes in marine and coastal systems from natural changes.

Sperm whales, beaked whales, and pilot whales have been spotted in waters deeper than

200 m off south Texas. Risso's dolphin have also been observed in the western Gulf of

Mexico, while short-finned pilot whales were also noted in a narrow zone in waters -350 m

deep off the southern coast of Texas. Bottlenose dolphins (Tursiops truncatus) appear to be

restricted in the Gulf of Mexico to shallow water, whereas striped and spotted dolphin

(Stenella spp.) distribution was less obviously correlated with water depth. The Stenella

species were observed most frequently in moderately shallow waters off southwest Florida.

The major concentrations of marine turtles in the Gulf of Mexico are located off Florida.

The offshore regions of southwest Florida had large numbers of turtles and low levels of

nesting in relation to eastern Florida. The role of these feeding habitats in the recovery or

continued decline of marine turtles in the U.S. waters has not been determined. Oil and gas

development may affect cetaceans and turtles in various ways. Seismic surveys employing

explosive charges (rarely the case) can be lethal at close range. Surface contact with oil

can threaten those species of cetaceans which rely on hair or fur for thermal insulation.

The long-term effects of accumulation of petroleum fractions through the food chain is

unknown. The ability of marine mammals to detect and avoid oil slicks is critical to

assessments of the potential impacts of oil. It was suggested that oil fouling creates

significant harm for small sea turtles. Petroleum impacted turtles have been found from the

Florida Keys to Cape Canaveral, an area associated with the Florida current. The

widespread dispersal of young turtles and petroleum residues in the ocean suggests that an

indeterminate number of turtles may die at sea.

Only a few scientific surveys assessing marine mammal distribution and abundance have

been conducted within the Gulf of Mexico. Twenty-six species of whales and dolphins

reportedly occur in the Gulf of Mexico based on historical records. The reported sightings of

baleen whales may be questionable. Sperm whales do occur in the Gulf, predominantly

outside the 200-1 ,000 m depth contours. The best understood cetacean species is the

bottlenose dolphin (T. truncatus), however, little is known about this species' behavior and

interactions. Systematic surveys are the only means of quantifying the presence of species

and the extent of their occurrence over a wide geographical area. Such surveys must be

made with adequate frequency to document daily, seasonal, and annual use of important

habitats. Radio tagging/tracking of individual cetaceans should provide information which

could be representative of populations as a whole. This technique and the monitoring of the

tagged individuals over the lifespan of a development should be given a high priority.

Qualitative information can be obtained over long periods of time from stranding records,

platforms of opportunity, hydrophones, and satellites. The southeastern stranding network

should be expanded. Because of the lack of information on many cetacean species, studies

should focus on bottlenose dolphins (Ttruncatus), one or more species of Stenella, sperm

whales, and baleen whales. Future studies should be coordinated efforts designed to

address Federal and State agency needs; these efforts should include sampling in areas

previously or currently under development, in areas where development is anticipated, and

in areas that may always remain pristine. The studies should be undertaken in order to

1 30 Living Marine Resources
better understand cetacean distribution, abundance, behavior, and ecology. Physiological effects of oil and gas development activities on cetaceans occur from a variety of sources,

including shock waves from the detonation of explosives; noise associated with all phases

of exploration and production; and surface contact and ingestion of oil. Three approaches

to gathering data on these effects include implementation of a stranding/necropsy program,

sampling of live caught T. truncatus, and a contingency oil spill investigation plan.

Effects of oil and gas activity on marine turtles can range from direct contamination and

mortality (associated with oil contact) to increased predation on neonates (due to attraction

to light on platforms where birds and large fish congregate). Several studies were

recommended to address these potential impacts, including a program to determine the

impact of oil on neonatal and juvenile sea turtles and their habitats. A second priority

identified was a study to evaluate the effects of crude oil on sea turtle eggs, embryos,

hatchlings, and nesting females. It was also suggested that another program address the

feeding biology, population structure, and seasonality of turtles off western Florida. In

addition, it was recommended that a study be initiated to determine habitat use and effects

of oil on sea turtles (especially Kemp's ridley turtle, Lepidochelys kempi; in Louisiana and

east Texas waters. Further, it was recommended that a synthesis of the data generated in

these studies (i.e., data regarding the interaction between OCS development and sea turtles)

be completed.

STUDY PRODUCT(S): Keller, C. E. and J. K. Adams (eds.). 1983. Proceedings of a

workshop on Cetaceans and sea Turtles in the Gulf of Mexico: Study Planning for Effects of

Outer Continental Shelf Development. A final report by the U.S. Fish and Wildlife Service

for the U.S. Department of the Interior, Minerals Management Service Gulf of Mexico OCS

Office, Metairie, LA. NTIS No. PB84-113265. FWS/OBS-83/03. Contract No.

14-12-0001-29118. v + 4-2 pp.

STUDY TITLE: Distribution and Abundance of Endangered and Vulnerable Mammals, Birds,

and Turtles.

COMPLETION DATE OF REPORT: February 1983.

CUMULATIVE PROJECT COST: $100,000.

KEY WORDS: South Atlantic; Straits of Florida; Eastern Gulf; Central Gulf; Western Gulf;

endangered species; cetaceans; turtles; workshop; development; impacts; mitigation;

Mississippi River; whales; dolphins; Florida; Texas; Florida Current; Kemp's ridley turtle;

Lepidochelys: bottlenose dolphin; Tursiops; Stenella; Gulf of Mexico Region.

Map #29118.2 Unavailable.

Living Marine Resources i 31
REPORT TITLE: Marine Birds of the Southeastern United States and Gulf of Mexico.

Part I, Gaviiformes through Pelecaniformes; Part II, Anseriformes; Part III, Charadriiformes.

MMS PUBLICATION NUMBER: Contract No. 14-12-0001-29134.

APPLICABLE PLANNING AREA(S): South Atlantic; Eastern Gulf of Mexico; Central Gulf of

Mexico; Western Gulf of Mexico.

BACKGROUND: This report summarizes the status of marine birds in the southeastern

United States and examines potential effects of Outer Continental Shelf (OCS) petroleum

resource development on these species. The information enables the Minerals Management

Service to identify aspects of OCS development that threaten marine bird populations and

allows managers to decide on energy resource development alternatives that minimize

damage to these populations.

OBJECTIVES: (1) To determine most likely occurrence of marine birds in future oil and gas

production areas; (2) to ascertain species most at risk from oil, gas, and ancillary activities

related to resource development; (3) to evaluate importance of southeastern United States

populations in relation to entire species distribution and abundance; and (4) to summarize

life history information of each species, emphasizing southeastern data.

DESCRIPTION: This report is a literature search, synthesis, and analysis emphasizing

literature and data concerning marine bird populations in the southeastern United States and

the Gulf of Mexico from North Carolina to Texas. Part I contains compiled information and

distribution maps concerning Gaviiformes (loons), Podicipediformes (grebes),

Procellariiformes (albatrosses, petrels, and shearwaters), and Pelecaniformes (tropicbirds,

frigatebirds, cormorants, gannets, boobies, and pelicans); Part II, Anseriformes (ducks,

geese, and swans); and Part Ill, Charadriiformes (phalaropes, gulls, terns, and skimmers).

SIGNIFICANT CONCLUSIONS: Susceptibility of birds to oil depends not only on their

juxtaposition in time and space, but also on currents, climatic factors, life history or annual

cycle stage, and general species behavior. Oil contamination may result in matted feathers;

death may soon follow from chilling or starvation or from the toxic effects of oil ingested

when preening is attempted. Oil from feathers may be transferred to incubating eggs and

may greatly reduce reproductive success.

STUDY RESULTS: Part I contains information on seasonal distribution and abundance of

39 marine birds species of the Orders Gaviiformes, Podicipediformes, Procellariiformes, and

Pelecaniformes that occur off southeastern shores of the United States and in the Gulf of

Mexico; Part II, 41 species of waterfowl in the Order Anseriformes; and Part III, 22 marine

bird species in the Order Charadriiformes. Additionally, each volume summarizes world-wide

distribution, habitat, food, and various aspects of the life history for species surveyed.

From this information, the susceptibility of the bird species to oil from oil and gas

development in the study area is predicted. Among the birds covered in Part I, loons and

grebes are considered most susceptible to oil pollution; cormorants, pelicans, and boobies

are moderately susceptible; and truly pelagic birds (most Procellariiformes, tropicbirds, and

frigatebirds) are least susceptible. Among the birds covered in Part II, seaducks and diving

ducks are most susceptible to oil pollution; other ducks, geese, and swans are relatively

Living Marine Resources 1 33
insusceptible because they are seldom found in areas where oiling is likely to occur. Large

concentrations of wintering, breeding, and migrant gulls and terns, covered in Part III, occur

within the survey area and in instances, comprise large proportions of worldwide or North

American populations. Consequently, Part Ill includes most of the marine birds that are

most likely to be detrimentally affected by oil resource development.

STUDY PRODUCT(S): Clapp, R. B., R. C. Banks, D. Morgan-Jacobs, and W. A. Hoffman.

1982. Marine Birds of the Southeastern United States and Gulf of Mexico. Part I.

Gaviiformes through Pelecaniformes. A final report by the U.S. Fish and Wildlife Service,

Office of Biological Services for the U.S. Department of the Interior, Minerals Management

Service Gulf of Mexico OCS Office, Metairie, LA. NTIS No. PB82-195850. FWS Report

FWS/OBS-82/01. Contract No. 14-12-0001-29134. 648 pp.

Clapp, R. B., D. Morgan-Jacobs, and R. C. Banks. 1982. Marine Birds of the Southeastern

United States and Gulf of Mexico. Part II. Anseriformes. A final report by the U.S. Fish

and Wildlife Service, Office of Biological Services for the U.S. Department of the Interior,

Minerals Management Service Gulf of Mexico OCS Office, Metairie, LA. NTIS

No. PB82-264995. FWS Report FWS/OBS-82/20. Contract No. 14-12-0001-29134.

505 pp.

Clapp, R. B., D. Morgan-Jacobs, and R. C. Banks. 1983. Marine Birds of the Southeastern

United States and Gulf of Mexico. Part Ill. Charadriiformes. A final report by the U.S. Fish

and Wildlife Service, Office of Biological Services for the U.S. Department of the Interior,

Minerals Management Service Gulf of Mexico OCS Office, Metairie, LA. NTIS No.

PB84-158773. FWS Report FWS/OBS-83/80. Contract No. 14-12-0001-29134. 869 pp.

STUDY TITLE: South Atlantic and Gulf of Mexico Marine Birds Literature Synthesis and

Analysis.

COMPLETION DATE OF REPORT: March 1982 (Part I); July 1982 (Part Il); September

1983 (Part III).

CUMULATIVE PROJECT COST: $190,000.

KEY WORDS: South Atlantic; Eastern Gulf; Central Gulf; Western Gulf; birds; seabirds;

biology; literature review; life history; abundance; synthesis; maps; distribution;

Gaviiformes; Podicipediformes; Procellariiformes; Pelecaniformes; Anseriformes;

Charadriiformes; impacts; oil spill; census.

Map #29134 Unavailable.

1 34 Living Marine Resources
ECOLOGICAL EFFECTS

These studies are designed to characterize the effects of oil and gas activity either

through comparison of current ecosystem data with earlier "benchmark" data or

through special studies oriented toward monitoring specific agents or activities or

groups of agents or activities. These latter studies have examined the discernible

impacts to the marine environment caused by offshore oil and gas activities, both

short-term effects in the vicinity of selected exploratory drilling rigs and long-term

effects in the Louisiana shelf region where offshore activities have occurred in

increasing densities for decades. The results of these studies are important in

understanding the actual impacts of offshore oil and gas activities, including both the

nature of the impact and a real extent of the impact. Information of this sort is used to

develop mitigating measures, where needed, to reduce or otherwise limit adverse

impacts due to oil and gas activities.

Ecological Effects 1 35
REPORT TITLE: Habitat Impacts of Offshore Drilling: Eastern Gulf of Mexico.

MMS PUBLICATION NUMBER: MMS 93-0021.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; South Atlantic.

BACKGROUND: More than 30 offshore exploratory wells have been drilled in the eastern

Gulf during the 1970s, 1980s, and early 1990s. Little was known about the aerial extent of

impact to the marine environment. As a result of concern about possible impacts, a

moratorium was placed on all OCS areas south of parallel 26° N. A National Academy of

Sciences panel review report in 1989 highlighted the lack of knowledge, as did a 1 989

State of Florida Governor's Report. A drilling moratorium for the northeastern Gulf of

Mexico is being sought by a coalition of many interested parties. This report presents the

finding of studies of six abandoned exploratory well sites in various environments ranging in

depths from 21 to 149 m.

OBJECTIVES: (1) To locate and systematically sample, video, and photograph six different

drill sites in the eastern Gulf of Mexico (the age of these sites ranged from 1 5 months to 1 7

years since drilling took place), (2) to conduct grain-size, mineralogical and elemental

analyses in order to map aerial extent of benthic impact, and (3) to determine whether drill

sites recovered to predrilling conditions over time.

DESCRIPTION: Six drill site locations provided by MMS were located using GPS and

examined using a 2-person research submersible. Using the submersible's collecting arm,

samples were taken in radial transacts extending outward from the borehole. Samples were

seived into 1 6 separate grain sizes and the percent of grains larger than 2 mm was used to

circumscribe a halo of impact surrounding the borehole. The mud fraction was analyzed for

barium, the weighting component of drill mud, and trace metals Cr, Fe, V. and Zn, using

Induction Coupled Neutron Activation Analysis(INAA). XRD was used to detect barite. A

continuous video record was made at each site along with selected still photographs.

Sites ranging in depth from 21 to 149 m consisted of Pensacola Block 996 No. 1 drilled in

1988, Destin Dome Block 56 No. 1 drilled in 1989, Gainesville Block 707 No. 1 drilled in

1985 Main Pass Block 255 No. 1 drilled in 1990, Florida Middle Ground 455 No. 1 drilled in

1986, and Florida Middle Ground Block 252 No. 1 drilled in 1974. Bottom habitats included

medium quartz sand, carbonate mud, coarse biogenic carbonate sand, hard limestone with

corals and gorgonians (tropical organisms), and relict reefs (pinnacle reef trend with deepwater gorgonian fauna).

SIGNIFICANT CONCLUSIONS: Areas impacted by cuttings and drilling debris, especially

used welding rods, ranged from as little as a few meters to over 1 3,000 m2 (over 3 acres).

Barium at levels above background (200 ppm is considered natural background) extended

beyond the range of our sampling pattern but clearly show a bullseye distribution of

decreasing values away from the borehole. High levels near boreholes were on the order of

50,000 to 1 50,000 ppm. At the shallow Gainesville Block 707 site, which had been

affected by two post-drilling hurricanes, barium was at background level except in one

sample taken at the borehole where the level was 8 times background level. Tropical fish

were abundant and 11 groupers were counted in and around the borehole.

Ecological Effects 1 37
At the oldest site (Middle Ground Block 252 No. 1 drilled 1 7 years ago), only background

barium levels were detected. Cuttings mixed with biogenic sand were rippled and little

debris was detected. No fish life was seen.

Main Pass Block 225, in 104 m of water, had been drilled adjacent to a pinnacle reef and a

reentry device with provisions for 4 wells was attached on the bottom. The site is within a

nepheloid layer. The bottom was dusted with fine rust-colored mud and water visibility was

very poor. The greatest impact at this site was a series of zigzag trenches apparently made

by the legs of a jack-up rig during either mobilization or demobilization. Large fish had been

attracted to the reentry structure.

The well head at Destin Dome Block 56 No. 1 was covered with a steel pyramid-shaped

protection device. This was the most heavily impacted site observed. The well was a very

deep test and produced more cuttings than the other wells. Fish were abundant.

Only one dive was made at Middle Grounds Block 455 No. 1, which was the deepest site

examined. The bottom consisted of burrowed lime mud with no plant life. The water was

149 m deep. Very large groupers hovered around the borehole, which was in the center of

a hexagon-shaped steel template half buried in the mud. In general, sites with structures,

open boreholes and/or debris served as artificial reefs and harbored the most diverse fish

fauna. Our observations indicate that sites in shallow water return more quickly to

predrilling conditions than do sites in more than 50 m of water. Storm waves and currents

can more easily remove drilling debris and barium, and the organisms that live in shallow

water grow much faster than those in deep cold waters.

STUDY PRODUCTS: Shinn E.A., Lidz, B.H., and Reich C.D. 1993, Habitat Impacts of

Offshore Drilling: Eastern Gulf of Mexico, OCS Study MMS 93-0021, and a 12-minute

Open-File video produced by USGS.

STUDY TITLE: Impact of Offshore Exploratory Drilling: Eastern Gulf of Mexico.

COMPLETION DATE OF REPORT: September 1993.

CUMULATIVE PROJECT COST: $152,856.

KEY WORDS: Cuttings, Drill Mud, Barium, Barite, Welihead, Trace Metals, Pinnacle Reef,

Destin Dome, Pensacola, Main Pass, Gainesville, Florida Middle Ground, Grain Size,

Template, Jack-Up Rig.

Map #14737 Unavailable.

1 38 Ecological Effects
REPORT TITLE: Dispersed Oil Toxicity Tests with Species Indigenous to the Gulf of

Mexico.

MMS PUBLICATION NUMBER: MMS 94-0021.

APPLICABLE PLANNING AREA(S): Straits of Florida; Eastern Gulf of Mexico; Central Gulf

of Mexico; Western Gulf of Mexico.

BACKGROUND: Testing on the fate and effects of oil and dispersed oil on marine

organisms can be traced back to large spills which occurred during the 1960's. Anderson et

al. (1974) identified the low molecular weight aromatic hydrocarbons as the primary

contributors to oil toxicity and described a method by which a water soluble fraction (WSF)

of the oil could be prepared for testing the effects of oil. "Water accommodated fraction"

(WAF) has also been used to reflect those hydrocarbon fractions which are water soluble

and the microscopic oil droplets found in suspension. Regulatory agencies are frequently

faced with decisions on how best to respond to oil spills, including the potential use of

dispersants. Decisions to use dispersants can result in tradeoffs that must weigh the

amount of oil which will be dispersed into the water column, thus affecting pelagic

organisms. In commercially-important fishery areas, such decisions can have environmental,

economic, and political implications.

OBJECTIVES: 1) To expose the eggs and/or larvae of seven Gulf of Mexico fish and

shellfish species and one Atlantic fish species to the WAF of two different Gulf of Mexico

oils, dispersed oil mixtures, and a single dispersant in controlled, flowthrough or static 96-hr

acute toxicity tests; 2) to characterize the chemical composition of the test oils and

exposure media (i.e., WAF, dispersed oil, dispersant) during various phases of acute toxicity

testing; 3) to summarize the results of acute toxicity testing and parallel chemical analyses

of exposure media on each of the species using gas chromatography (GC), GC/mass

spectrometry (GCIMS), and GC/MS with selected ion monitoring (GC/MS-SIM).

DESCRIPTION: Static and flowthrough exposure methods were utilized on egg and larval

stages of commercially-important species from the Gulf of Mexico including brown shrimp

(Penaeus aztecus), white shrimp (P. setiferus), blue crab (Caiinectes sapidus), eastern oyster

(Crassostrea virginica), red drum (Sciaenops ocellatus), inland silverside (Menidia beryiina),

and spot (Leiostomus xanthurus). As attempts to secure eggs and larvae of gulf menhaden

(Brevoortia patronus) were unsuccessful, a congener (Atlantic menhaden, Brevoortia

tyrannus) was evaluated using study-specific acute toxicity testing protocols. Mysids

(Mysidopsis bahia) were also evaluated in a chronic toxicity assessment. Test organisms

were exposed to the WAF of two different oils (i.e., Western and Central Gulf of Mexico

OCS) and dispersed oil mixtures, as well as a single dispersant (Corexit 9527). Speciallydesigned flowthrough exposure chambers were developed, evaluated, and utilized during the

study. LC50 values and Toxicity Index (TI) determinations were made for all species. The TI

is a relative measure of toxicity calculated from the product of exposure concentration and

time (e.g., ppm x hours = ppm-hrs). TI values were determined for total naphthalenes,

total petroleum hydrocarbons (TPH), and BTEX compounds (i.e., benzene, toluene,

ethylbenzene, xylenes).

Ecological Effects 1 39
SIGNIFICANT CONCLUSIONS: Replication between flowthrough exposures was good,

particularly with regard to hydrocarbon exposures. Agreement in the static exposures was

less evident, suggesting that greater variability is likely in toxicity results originating from

this exposure method. Embryonic stages of the species tested exhibited lower sensitivity

than early larval stages. The overall sensitivity of fish versus invertebrates appeared to be

similar. Invertebrates performed better as test organisms, as overall control survival was

better. The naturally high mortality of fish larvae compounded efforts to obtain acceptable

test results. Significantly higher concentrations of total naphthalenes and TPH were

measured in the dispersed oil mixtures compared to the WAF; however, the dispersed oil did

not reflect a correspondingly greater toxicityl BTEX was measured at levels an order of

magnitude higher in the WAF than in the dispersed oil mixtures. These results suggest that

the BTEX compounds were a possible source of toxicity in the WAF exposures, whereas

naphthalenes may have been the primary cause of toxicity in the dispersed oil exposures. In

most exposures, a majority of the toxicity occurred within the first 24 hrs.

STUDY RESULTS: The two oils showed minor chemical differences. The Central Gulf oil

exhibited higher concentrations of chrysenes, phenanthrenes, fluorenes, and

dibenzothiophenes. Naphthalenes were present in the highest concentrations in both oils

(i.e., 420-510 g/g) and were generally several times greater than the other polynuclear

aromatic hydrocarbon compounds analyzed. Hydrocarbon concentrations at the end of the

study (i.e., in Month 19) revealed several basic differences from the initial analyses.

Naphthalenes and fluorenes were generally higher, while the phenanthrenes,

dibenzothiophenes, and chrysenes exhibited lower or similar concentrations when compared

to initial measurements. Differences in concentrations may suggest variability within the

testing method rather than being indicative of any real change in the oils over time.

Dispersant characterization indicated minimal naphthalerie and phenanthrene concentrations

of 0.16 and 0.012 /2g/g, respectively. Static tests tended to have the highest overall TPH

concentrations with the dispersed oil levels being 4-5 times greater than that measured in

the WAF. Flowthrough concentrations tended to be more variable without the clear

distinctions seen in the static tests. BTEX concentrations integrated over 96-hr exposures

did not differ markedly between the two oils tested. BTEX concentrations in the static

system were at least an order of magnitude higher than in the flowthrough system.

Similarly, concentrations in the WAF were an order of magnitude greater than in the

dispersed oil mixtures. The range of variation between samples was generally less than

30%. In spite of the order of magnitude differences in concentrations, the majority of the

BTEX determinations noted for both the dispersed oil mixtures and the WAF in the

flowthrough system were lost within the first 6 hrs, with concentrations close to detection

limits within 24 hrs. Brown shrimp were tested with the Western Gulf WAF and dispersed

oil. All of the toxicity in the two exposures occurred within the first 24 hrs with little to no

toxicity observed in subsequent days, consistent with hydrocarbon patterns where the

majority of the materials were lost within the first 24 hrs of exposure. White shrimp tests

were conducted with both the Western and Central GuUI oils using postlarvae at ages of

1 5 days (Central Gulf oil) and 22 days (Western Gulf oil). The dispersant itself had a

measured LC50 of 11 .9 mg/I. As with the oil exposures, the majority of the toxicity

occurred within the first 24 hrs. After the 96-hr exposures were completed, surviving

shrimp were grown for an additional 30 days in clean seawater and weighed. Control

weights in the two sets of test were consistent but slightly higher in the Central Gulf oil

exposures, suggesting effects of stress. Effects on growth from the exposures themselves

1 40 Ecological Effects
were noticeable in the surviving shrimp at the highest concentration in the Western Gulf

dispersed oil and to a lesser extent in WAF. No effects were seen on growth in the 50-ppm

concentration of the dispersant, consistent with the findings from the acute toxicity testing.

In the Central Gulf exposures, reduced growth was noted in the 25-ppm dispersant

concentration and in the 100% WAF. Slightly lower (though not significant) weights were

observed in the 25-ppm concentration of the dispersed oil. These results also closely

paralleled toxicity testing results. Blue crab exposures were conducted with both Central

and Western Gulf oils. Based on results of two dispersant only tests, similar sensitivities to

the dispersant were obtained. Similarly, the results from WAF exposure did not differ

greatly. While most of the toxicity in the dispersed oil tests appeared to occur within the

first 24 hrs, mortalities in the WAF and dispersant mixtures were most evident after the first

24 hrs, suggesting a greater sensitivity to the dispersed oil. However, it was also suggested

that molting may have occurred at a particularly critical period with regard to the severity of

effects and may explain the differences observed between the two oils. Oysters were

exposed in static tests to the dispersant and to dispersed oil mixtures; no tests were

conducted with WAFs due to difficulties encountered during spawning. In addition to the

determination of an EC50 value for oysters, lowest observed effect concentrations (LOEC)

and no observed effects concentrations (NOEC) were calculated using the Kruskal-Wallis

method. The dispersant was particularly toxic to the embryo/larval stages, resulting in an

EC50 <6.25 ppm. Similarly, the dispersed oil mixtures had statistically significant effects at

the lowest concentrations tested. In exposures to the Central Gulf dispersed oil, the EC50

was <6.25 ppm dispersed oil. The Western Gulf dispersed oil had a lower toxicity than the

Central Gulf dispersed oil with an NOEC of 6.25 ppm and an LOEC of 12.5 ppm.

Tests with embryos and larvae of inland silverside were conducted under both static and

flowthrough exposures. Numbers of surviving embryos and larvae were similar after 96 hrs

in the three different exposure media. The 96-hr toxicity tests were followed by recovery to

Day 9, at which time the fewest survivors overall were found in the WAFs and dispersant

exposures. When compared to controls, the 50% and 50 mg/I concentrations showed a

similar rate of mortality in the three exposures, suggesting a delayed response. A

subsequent test confirmed the relative insensitivity of the fish when the exposure was

begun in a late embryonic stage. In these tests, equally high hatching rates were measured

in all of the exposures. No effects on fry survival were measured in the three exposures at

the end of the 96-hr tests. By comparison, a static test exposure had effects in reducing

hatching rates in a 75% and 50% WAF, possibly due to the effects of higher exposure

concentrations than those observed in flowthrough tests. Tests which had begun with the

larvae produced similar results during exposures to Western and Central Gulf oils. Atlantic

menhaden were subjected to static exposure conditions because of sensitivity to

flowthrough testing protocols. Test specimens were received as embryos within

approximately 36 hrs after their release from females. Tests were initiated with embryos

and hatching occurred within the first 24 hrs of the test. Results were obtained in 48-hr

exposures because of the significant control mortality. In spite of the shortened exposure,

test results provided clear patterns of toxicity. Two oils were tested and produced similar

results iii a comparison of the WAF and dispersed oil; only one acceptable test was achieved

in the dispersant exposures. Sensitivity of this species was comparable to that observed for

spot. Toxicity testing of spot was conducted under similar conditions as those realized for

Atlantic menhaden. Spot appeared to be more sensitive to the Central Gulf oil. As with

Atlantic menhaden, test results were obtained for 48-hr exposures due to significant control

Ecological Effects 141
mortalities. Hatching success and fry survival were evaluated in various exposures to

Central and Western Gulf oils. In both sets of tests, similar results were obtained, indicating

that hatching success was similar between WAFs and dispersed oil exposures and that

effects were most evident in only the highest exposure concentrations after 48 hrs. In both

cases, 96-hr survival was lowest in the dispersed oil mixtures. Tests with red drum were

limited due to difficulties encountered in maintaining controls. In those tests where

acceptable results were obtained for the two oils, this species proved to be relatively

insensitive. Hatching success realized by test organisms exposed to the Western Gulf oil in

a flowthrough system was also evaluated. Hatching success was affected only at the

highest concentration of the dispersed oil and in the higher concentrations of the dispersant.

The WAF did not appear to significantly affect hatching success. In summary, significantly

higher concentrations of total naphthalenes and TPH were measured in the dispersed oil

mixtures compared to the WAF; however, the dispersed oil did not reflect a correspondingly

greater toxicity. BTEX was measured at levels an order of magnitude higher in the WAF

than in the dispersed oil mixtures. Results suggest that the BTEX compounds were a

possible source of toxicity in the WAF exposures, whereas naphthaleries may have been the

primary cause of toxicity in the dispersed oil exposures.

STUDY PRODUCT(S): Fucik, K. W., K. A. Carr, and B. J. Balcom. 1994. Dispersed Oil

Toxicity Tests with Biological Species Indigenous to the Gulf of Mexico. OCS Study/MMS

94-0021. A final report prepared by Continental Shelf Associates, Inc. for the U.S.

Department of the Interior, Minerals Management Service, Gulf of Mexico OCS Region, New

Orleans, LA. MMS Contract No. 14-35-0001-30617. 97 pp. + appendices.

STUDY TITLE: Dispersed Oil Toxicity Tests with Species Indigenous to the Gulf of Mexico.

COMPLETION DATE OF REPORT: August 1994.

CUMULATIVE PROJECT COST: $272,795.

KEY WORDS: Straits of Florida; Eastern Gulf; Central Gulf; Western Gulf; acute toxicity

testing; chemistry; invertebrates; fish; larvae; eggs; hydrocarbons; dispersant; Gulf of

Mexico Region.

Map #30617 Unavailable.

1 42 Ecological Effects
REPORT TITLE: Quality Control for MAFLA IV and South Texas II Investigations.

MMS PUBLICATION NUMBER: Contract No. 08550-CT5-49.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico;

Western Gulf of Mexico.

BACKGROUND: A comprehensive quality control program was conducted in support of

the Mississippi, Alabama, and Florida (MAFLA) Outer Continental Shelf (OCS) Monitoring

Study and South Texas OCS Baseline Program. Such quality control programs are needed in

order to be able to make comparative assessments of chemical analyses from different

laboratories and for individual studies.

OBJECTIVES: (1) To provide trace metals analyses and quality control for samples of

suspended particulate matter, biota, and sediment from the MAFLA Monitoring Study and

South Texas OCS Baseline Program.

DESCRIPTION: A total of 241 samples including 10 suspended particulate, 31

zooplankton, 19 paint chip samples, 75 sediment, and 106 epifauna samples were analyzed

for quality control trace metal testing. Suspended particulates, zooplankton, epifauna, and

sediments were analyzed from the South Texas OCS Baseline Program. Zooplankton, paint

chips, sediments, and epifauna were tested from the MAFLA area, and sediments and

epifauna from the MAFLA Rig Monitoring Study. All samples were measured for cadmium,

copper, lead, nickel, and vanadium with additional analyses on specific samples for barium,

iron, and zinc.

Analytical methodologies which were investigated included hot nitric acid digestion, liquid

fire digestion, and a 10-day procedure based on the principle of the Parr bomb. Testing of

the procedures was accomplished by digesting aliquots of four biota pools (i.e., shrimp,

oysters, sand dollars, and flounder). Based on results of an accuracy test, the 10-day

procedure was selected for digestion of epifauna and zooplankton samples. Flame and

flameless atomic absorption spectrophotometry (AAS) were used to make the metals

determinations.

SIGNIFICANT CONCLUSIONS: Average concentrations of cadmium and copper in

zooplankton samples tended to be higher in the MAFLA area while chromium, lead, and

vanadium were higher in South Texas. Nickel levels were similar in the two areas.

Concentrations of these metals in suspended particulate samples were generally two or

more orders of magnitude less than those in the zooplankton. Metals concentrations in

epifauna samples were generally lowest in South Texas, intermediate from the MAFLA Rig

Monitoring Study, and highest in the MAFLA area.

Sediment samples in the South Texas, MAFLA, and MAFLA rig monitoring areas gave similar

results with a few exceptions. Barium was lower in the MAFLA area as compared to the

other two study sites. Chromium was higher in the rig monitoring samples, and vanadium

was lower in the MAFLA area.

Ecological Effects 1 43
Good agreement was reached between the measured and actual concentrations in reference

samples received from the National Bureau of Standards (NBS).

STUDY RESULTS: Suspended particulate matter samples were all obtained from the South

Texas baseline area. Metals determinations were made for vanadium, cadmium, lead,

nickel, copper, chromium, and zinc.

In analyzing biota, several experiments were conducted. A hot nitric acid digestion

procedure was attempted in the first experiment which gave poor results and was lengthy.

Good agreement was obtained on NBS standard reference materials but poor precision was

obtained on shrimp pool samples. Precision was better for Food and Drug Administration

(FDA) oysters and NBS tuna than for the shrimp.

Experiment two was designed to determine whether a 32-h acid digestion was required for

accurate analysis. Analyses for cadmium, chromium, lead, and nickel did not demonstrate

sufficient sensitivity or reproducibility to provide comparable time-dependent data. Copper,

iron, and zinc determinations suggested that the optimum digestion time was 8 h.

In experiment three, another digestion method was attempted because of poor results with

the nitric acid digestion. This digestion involved a perchloric acid-nitric acid procedure.

Poor results were obtained with this method which included lack of precision and accuracy.

In addition, the method was hazardous for use with biota samples and was therefore

abandoned.

In the fourth experiment, a Parr bomb principle was employed to test digestion efficiency.

The actual procedure employed was the 10-day procedure which used pressure

development by the action of nitric acid on the biota. The procedure gave the best

precision of all the methods tested and gave good recovery of spikes for all metals tested,

with the exception of zinc. A follow-up experiment was designed to determine if the 10-

day nitric acid procedure could provide accurate data for an NBS reference standard.

Observed precision with the method was good.

Sufficient sample volume for zooplankton analysis was provided only for the South Texas

region. Precision in the samples was very good for all trace metals of interest and the

recovery of spikes was good. This indicated that the analyses for zooplankton were in

control. In South Texas samples, only copper and zinc were present in sufficient

concentrations to be detected by flame AAS. In the MAFLA area samples, the majority of

the trace metals analyzed could be detected by flame AAS. Cadmium, chromium, lead,

nickel, and vanadium required flameless AAS. A graphite furnace was used for all trace

elements except copper and iron in the MAFLA Rig Monitoring Study. Vanadium and

chromium could be detected in most of these samples. Percent recovery of spikes in these

samples ranged from 86% to 95%.

Partial and total digestion methods were attempted for sediment samples. The partial

method used nitric and hydrochloric acids for leaching of metal content, whereas the total

method used hydrofluoric and perchloric acids. Comparison of the two methods showed

similar values for copper, lead, nickel and zinc. Chromium, vanadium, and especially barium

1 44 Ecological Effects
were higher in the total digestion samples. Precision and accuracy of the two techniques

were similar.

STUDY PRODUCT(S): McKown, M. M. and J. G. Montalvo. 1976. Quality Control for

MAFLA IV and South Texas II Investigations. A final report by the Gulf South Research

Institute for the U.S. Department of the Interior, Bureau of Land Management Gulf of

Mexico OCS Office, New Orleans, LA. NTIS No. PB8O-216302. Contract No. 08550-CT5-

49. 189 pp.

STUDY TITLE: Trace Metals Quality Control Analyses.

COMPLETION DATE OF REPORT: 1976.

CUMULATIVE PROJECT COST: $110,000.

KEY WORDS: Eastern Gulf; Central Gulf; Western Gulf; Mississippi; Alabama; Florida;

Texas; baseline; quality assurance; trace metals; suspended particulates; sediment;

epifauna; zooplankton; spectrophotometry; interlaboratory comparison.

Ecological Effects 145
OUL O MEXICO t0IOM STUDY AREA FOR TRACE METALS QUALITY CONTROL ANALYSES, MAFLA AND SOUTH TEXAS OCS INVESTIGATIONS.0 55 50 75 00 KILOM

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STUDY AREA FOR TRACE METALS QUALITY CONTROL ANALYSES. MAFLA AND SOUTH TEXAS OCS

INVESTIGATIONS.
REPORT TITLE: A Numerical Modelling and Observational Effort to Develop the Capability

to Predict the Currents in the Gulf of Mexico for Use in Pollutant Trajectory Computation: A

Guide to a General Circulation Model of the Gulf of Mexico.

MMS PUBLICATION NUMBER: Contract No. 08550-1A5-26.

APPLICABLE PLANNING AREA(S): Straits of Florida; Eastern Gulf of Mexico; Central Gulf

of Mexico; Western Gulf of Mexico.

BACKGROUND: Increasing levels of offshore oil and gas development have subsequently

increased the probabilities for accidental releases of oil. Such spills can have significant

environmental effects. In order to anticipate and mitigate the effects of such spills, it is

necessary to be able to predict the trajectory and possible landfalls of released oil. Since

such trajectories are largely a function of ocean surface currents, predictive capabilities can

be developed through the use of numerical models which simulate currents in the vicinity of

a spill. This predictive capability, which may be applied further to a modeling of the

movement of an oil spill, was determined to be of particular concern within the Gulf of

Mexico, a region of historic and future oil and gas development activity.

OBJECTIVES: (1) To modify an existing numerical model for application to the Gulf of

Mexico; (2) to evaluate the ability of the model to adequately simulate the circulation of the

Gulf of Mexico using various types and distributions of data; and (3) to describe the Gulf of

Mexico circulation using the results of the model.

DESCRIPTION: In order to model or predict circulation patterns within the Gulf of Mexico,

a mathematical model was developed using a series of approximations. First, the ocean was

assumed to be a Boussinesq fluid (i.e., the density of the ocean differs only slightly from a

reference state in which entropy and salinity are constant and there is no motion).

Secondly, the ocean was assumed to be in hydrostatic balance. By definition, this means

that the vertical balance of forces differs only slightly from a reference state of no motion.

The third approximation was based on the fact that the surface of the ocean does not

coincide with the geoid even if wind waves and tidal fluctuations are neglected. Fourthly,

the equations which were used governed only large scale motion. Finally, the model

assumed that the frictional drag of flow on the bottom was negligible over most of the

basin. It was recognized that this assumption was not applicable (i.e., was incorrect) in

those situations where strong currents extend to the bottom. In these cases, a simple

bottom drag coefficient was included. The actual computer program was a modification of

a previously developed model.

The interior and boundary conditions for the model were derived from data provided by the

National Oceanographic Data Center and from cruises conducted as part of the present

study. Monthly circulation of the Gulf of Mexico was simulated using a broad range of

input and boundary conditions. Specifically, test calculations were performed on a grid with

seven vertical layers (70, 151, 297, 500, 703, 849, and 930 m) and a horizontal resolution

of 0.5 degree of longitude and latitude. Time step was kept constant at 0.5 hours and the

vertical coefficient of eddy viscosity was 1 cm2/s. Variable parameters included transport,

horizontal coefficient of viscosity, boundary conditions, wind stress, and wide shelf. The

Ecological Effects 1 49
ability of the model to simulate the observed circulation was demonstrated through a series

of comparisons of circulation model solutions with results from a geostrophic model.

This report is a companion to the final report entitled "A Numerical Modelling and

Observational Effort to Develop the Capability to Predict the Currents in the Gulf of Mexico

for Use in Pollutant Trajectory Computation: Model Studies of the Circulation in the Gulf of

Mexico," also prepared under this contract.

SIGNIFICANT CONCLUSIONS: A numerical model was developed to characterize general

circulation patterns within the Gulf of Mexico. Results of simulations compared favorably

with results obtained from a geostrophic model. Sensitivity of the models to transport,

horizontal coefficient of viscosity, boundary conditions, wind stress, and a wide shelf were

tested. Changing boundary conditions in the model had only a minor effect on model

results. Among the most important results noted was the fact that large changes in the

applied wind stress and in the transport through the Straits of Yucatan and Florida had

relatively little effect on interior circulation of the Gulf of Mexico basin. At the same time, a

1 7% reduction of transport through the Straits of Yucatan and Florida caused significant

changes in the transport only near the Cuban coast, suggesting that the interior balance

remains unchanged and adjustment to the transport boundary conditions occurs only in a

narrow boundary layer along the Cuban coast. Increasing the vertical viscosity had a

significant effect in decreasing transport in the Gulf and changing the characteristics of the

Loop Current. Improbable currents were predicted when the model was extended onto the

shallow shelf which led to the expanded grid being rejected from the model. Instead, a

small amount of bottom friction is added to the model whenever the grid is only one layer

thick.

STUDY RESULTS: Under varying boundary conditions, only minor differences were seen

between zero gradient and geostrophic boundary conditions. In another experiment, flow

through the Straits of Yucatan and Florida was tested under two conditions. The results

were essentially the same in the western Gulf and remarkably similar in the eastern Gulf. It

was determined that the main effect of under-specifying the transport by 1 7% was to cause

a recirculation of water within the Loop Current and a northwestern flow of water along the

northwestern coast of Cuba. Away from the Cuban coast, the circulation is affected only

slightly. This led to the conclusion that small errors in transport specified at the boundary

does not radically affect the interior circulation in a diagnostic experiment.

Under conditions with and without wind stress, close similarity between the two simulations

was obtained. For the most part, wind stress had a negligible effect. The differences were

mainly in regions where circulation was weakest. Differences in velocities for the surface

and deeper layers was negligible. Several small differences were also noted in the current

on the Campeche Bank where wind stress caused some enhancement in flow.

Several experiments were run to test the sensitivity of the model to viscosity changes.

Increasing viscosity by a factor of five reduced transport in the central western gyre by

35% and the transport in the Loop Current by 28%. Mean kinetic energy was decreased by

29%. Changing viscosity also caused the Loop Current to become smoother and broader,

coupled with reduction in the stream function gradients.

1 50 Ecological Effects
In another experiment, the effect of extending the shallow shelves on the model was tested.

To do this, the top layer of the model simulation was extended shoreward to the 1 5 m

isobath. In the expanded grid, a strong current appeared flowing from the Mississippi Delta

southward across the west Florida Shelf. This flow replaced a much weaker southward

flow in a test without the expanded shelf. The strong Delta current, with velocities as large

as those in the Loop Current, were determined to be unrealistic. In both tests, strong

currents were defined along the Campeche Bank west of 88°W Long. Although predicted

current speeds were probably too large, current direction was consistent with the interior

flow. Based on these results, the expanded grid was rejected.

STUDY PRODUCT(S): Behringer, D. W., R. L Molinari, and J. F. Festa. 1976. A

Numerical Modelling and Observational Effort to Develop the Capability to Predict the

Currents in the Gulf of Mexico for Use in Pollutant Trajectory Computation: A Guide to a

General Circulation Model of the Gulf of Mexico. A final report by the Atlantic

Oceanographic and Meteorological Laboratory, National Oceanic and Atmospheric

Administration for the U.S. Department of the Interior, Bureau of Land Management Gulf of

Mexico OCS Office, New Orleans, LA. Contract No. 08550-1A5-26. iv + 80 pp.

STUDY TITLE: Model Studies of the Circulation in the Gulf of Mexico.

COMPLETION DATE OF REPORT: May 1976.

CUMULATIVE PROJECT COST: $187,763.

KEY WORDS: Straits of Florida; Eastern Gulf; Central Gulf; Western Gulf; physical

oceanography; modeling; model; currents; eddy; shelf; Florida Straits; Yucatan Straits; wind;

wind forcing; Loop Current; Gulf of Mexico Region.

Map #1A5-26.2 Unavailable.

Ecological Effects 1 51
SOCIOECONOMICS

The basis for the socioeconomic studies is the implementation and fulfillment of the

requirements of the OCS Lands Act Amendments and the need for socioeconomic

information for multiple resource management on the OCS in accordance with the

purposes of this Act. The Act provides for assistance to anticipate, plan, and protect

from impact the human environment in those State and local governments in which

potential changes in the social, governmental, or economic infrastructure may occur

from oil and gas exploration, development, and production activities.

Subsequent to the leasing and developing of any area or region, studies must be

conducted to monitor the human, marine, and coastal environments "in a manner

designed to provide time-series and data-trend information that can be used for

comparison with any previously collected data for the purpose of identifying the causes

of such changes."

Socioeconomics 1 53
REPORT TITLE: Indicators of the Direct Economic Impacts Due to Oil and Gas

Development in the Gulf of Mexico. Results of Year I. Executive Summary; Vol. I,

Narrative; Vol. II, Exhibits.

MMS PUBLICATION NUMBER: MMS 86-0014, 86-001 5, 86-0016.

APPLICABLE PLANNING AREA(S): Straits of Florida; Eastern Gulf of Mexico; Central Gulf

of Mexico; Western Gulf of Mexico.

BACKGROUND: Primary economic impacts from outer continental shelf (OCS) leasing

include the employment, wages, and salaries accounted for by the companies that are

directly involved in the exploration for and development of OCS hydrocarbon resources.

Secondary impacts include the expenditures by these companies for contracts, services, and

other purchases, and the associated employment and salary impacts. Primary and

secondary economic impacts affect socioeconomic conditions such as population,

demographic and commute-to-work patterns. The collection of economic data is necessary

to evaluate the socioeconomic impacts related to oil and gas development in offshore areas.

OBJECTIVES: (1) To measure the primary direct economic impact of offshore oil and gas

exploration, development, and production in 1984; (2) to determine the geographic

distribution of primary direct impacts of offshore oil and gas activity; (3) to document the

relationship between place of work and place of residence for personnel employed by

offshore producers; (4) to measure the direct secondary economic impact of contracts,

services, and other purchases made by offshore oil and gas exploration and production

companies; and (5) to develop a framework and set of reference data for estimating the

combined direct primary and direct secondary economic impacts per unit of activity.

DESCRIPTION: Data for this project were supplied by nine offshore operators in the Gulf

of Mexico acting as a Socioeconomic Subcommittee to the Offshore Operators Committee.

Information was provided on producer employment records for 1984, producer expenditure

records for 1 984, and budget documents for specific projects or activities undertaken in

1 984. The data were then used to generate numbers on direct producer employment and

wages at the county/parish level. County/parish allocations of employment and income

were based on the residence zip code of each employee. Application of key business ratios

for each service industry to total expenditures by offshore producers was used to derive

employment resulting from the purchases of goods and services. Physical descriptions of

activities were converted to expenditures based on actual detailed project records supplied

by the participating companies. All data supplied by the offshore producers was exclusively

for expenditures and employment associated with activities in the Gulf of Mexico region.

SIGNIFICANT CONCLUSIONS: The direct primary effect of oil and gas operations in the

Gutf of Mexico measured in employment, wages, and salaries.. These totaled $853 million in

wages, $8.75 billion in expenditures for purchased goods and services, and 23,935 personyears of employment with oil companies. Secondary effects were associated with the

handling, refining, and processing of offshore oil and gas. These economic impacts included

$637 million in wages and salaries and 21,572 person-years of employment. In all states,

an estimated 142,860 person-years of employment were associated with Gulf operations.

Socioeconomics 155
STUDY RESULTS: Louisiana accounted for 21,857 of the 23,935 employee positions

associated with Gulf offshore oil and gas producers. This generated a payroll of

$776,696,436 in the State in 1984. More than 80% of the offshore and 90% of the

onshore Gulf of Mexico workers reported to work sites in Louisiana. An estimated 14,054

onshore producer employees reported to work sites throughout the region with 13,500 in

Louisiana and 500 in Texas. In Louisiana, approximately 10,000 came from the New

Orleans area. Offshore producer employees came from 26 states with 20 states having

very slight employment impacts of two to eight persons. Georgia, Oklahoma, and

Tennessee supplied approximately 20 persons each. Louisiana provided 20,000, Mississippi

had 1,960, Texas had 1,413, Alabama had 475, and Florida had 205.

The 1 984 producer purchases, expenditures, and contracts resulted in an estimated $2.59

billion in wages and salaries to employees of contractors and other general businesses.

These businesses had an employment impact of 97,500 full-time positions. Of these,

28,955 were located offshore, 20,085 had an offshore component, and 48,347 were

located exclusively on land. Expenditures by producers resulted in purchases by the

contract and support firms of $3.9 billion. These purchases included raw materials,

operating expenses, capital purchases, and subcontracts with other offshore support

industries. The purchases were significant because many were made locally and resulted in

subsequent indirect and induced economic impacts.

Approximately 10,566 person-years of employment were generated at oil refineries as a

result of offshore oil and gas activities. Of this, 9,054 were in Louisiana and 1,512 were in

Texas. This resulted in $306 million in wages in Louisiana and $51 million in Texas. Gas

processing plants supported an estimated 11 ,006 person-years of employment which was

almost equally split between Texas and Louisiana. This resulted in $137 million in wages in

Louisiana and $142 million in Texas.

STUDY PRODUCT(S): Centaur Associates, Inc. 1 986. Indicators of the Direct Economic

Impacts Due to Oil and Gas Development in the Gulf of Mexico. Results of Year I.

Executive Summary. A final report for the U.S. Department of the Interior, Minerals

Management Service Gulf of Mexico OCS Region, Metairie, LA. NTIS No. PB86-246188/AS.

MMS Report 86-0014. Contract No. 14-12-0001-30178. 33 pp.

Centaur Associates, Inc. 1986. Indicators of the Direct Economic Impacts Due to Oil and

Gas Development in the Gulf of Mexico. Results of Year I. Vol. I, Narrative. A final report

for the U.S. Department of the Interior, Minerals Management Service Gulf of Mexico OCS

Region, Metairie, LA. NTIS No. PB86-2461961AS. MMS Report 86-0015. Contract No. 14-

12-0001-30178. 100 pp.

Centaur Associates, Inc. 1 986. Indicators of the Direct Economic Impacts Due to Oil and

Gas Development in the Gulf of Mexico. Results of Year I. Vol. II, Exhibits. A final report

for the U.S. Department of the Interior, Minerals Management Service Gulf of Mexico OCS

Region, Metairie, LA. NTIS No. PB86-246204fA5. MMS Report 86-0016. Contract

No. 14-12-0001-30178. 700+ pp.

STUDY TITLE: Analysis of Indicators for Socioeconomic Impacts Due to Oil and Gas

Activities in the Gulf of Mexico.

1 56 Socioeconomics
COMPLETION DATE OF REPORT: January 1986.

CUMULATIVE PROJECT COST: $270,465.

KEY WORDS: Straits of Florida; Eastern Gulf; Central Gulf; Western Gulf; Louisiana;

Texas; Alabama; Florida; cultural impacts; exploratory drilling; development; impacts;

employment; expenditures; labor.

Socioeconomics 1 57
30° 28° - 28° 27° -26° 1. J / '° EN8AC. 2000 m88° KEY MAP 67° EASTERN GULF OF MEXICO REGION STRAITS OF FLORIDA88° -28° - 24° 88° 84° 83° TORT MYE3 KEY WEST 82° 8 1° 200 0 26 50 75 00 KIL

80° STUDY AREA FOR ANALYSIS OF INDICATORS FOR SOCIOECONOMIC IMPACTS DUE TO OIL AND GAS DEVELOPMENT IN THE GULF OF MEX

0 26 50 75 
4 ) BEAUOT SIANA HOUSTdN OG N CITY 6v 0UL O MEXICO flEOION 0 26 60 76 

STUDY AREA FOR ANALYSIS OF INDICATORS FOR SOCIOECONOMIC IMPACTS DUE TO OIL AND GAS DEVELOPMENT IN THE GULF OF M
CULTURAL RESOURCES

All Federal agencies are required to ensure that Federal undertakings affecting

properties included in, or eligible for inclusion in, the National Register of Historic

Places be submitted to the Advisory Council on Historic Preservation for review and

comment prior to the agency's approval of any such undertaking. To determine

whether properties eligible for the National Register will be affected by proposed lease

offerings, Executive Order 11 593 requires Federal agencies to locate, inventory, and

nominate properties under their jurisdiction or control to the National Register. On the

OCS, compliance with this legislation has been accomplished by taking a protective

stance based on avoidance of areas potentially containing significant cultural

resources. To carry out such a program, predictive models for uninventoried cultural

resources are a basic management tool built into MMSs cultural resource management

program. These predictive models are generated by using information on site locations

from extensive literature searches and through comparison with terrestrial site

analogues.

Cultural Resources 161
REPORT TITLE: Cultural Resources Evaluation of the Northern Gulf of Mexico Continental

Shelf. Vots. I through III.

MMS PUBLICATION NUMBER: Contract No. 08550-MU5-40.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico;

Western Gulf of Mexico.

BACKGROUND: In 1974, the Interagency Archeological Services Division in conjunction

with the U.S. Department of the Interior initiated investigations of potential impacts of

offshore oil and gas leasing activities on submerged archeological resources. From these

studies, it was surmised that each lease block need not be surveyed intensively, but that a

system should be developed to identify areas of probable cultural resource occurrence (e.g.,

shipwreck and prehistoric human habitation sites). This information would allow managers

to develop site-specific archeological hazards surveys in areas such as the Gulf of Mexico

before damage from exploration activities occurred.

OBJECTIVES: (1) To identify potential aboriginal habitation sites based on particular

geological indicators on the Outer Continental Shelf (OCS) and coastal geology and

prehistoric archeology from the Gulf of Mexico; (2) to locate probable and existing

shipwreck sites; (3) to develop a map of cultural resource zones for the OCS; and (4) to

recommend search and recovery procedures for shipwrecks and submerged habitation sites.

DESCRIPTION: A review of pertinent literature concerning Quaternary geology, prehistoric

archeology, and shipwreck archeology was completed. From the geological synthesis,

geometric models of frequently occurring coastal physiographic features were developed

and used to classify and identify similar but relict features on the OCS. The late Quaternary

was investigated using maps and published descriptions to locate particular relict

physiographic units. The eustatic sea, isostatic, and tectonic compounds of level

fluctuations that resulted in the exposure of habitable area were studied. For prehistoric

archeology, the Gulf of Mexico was divided into eastern, central, and western areas. From

archeological literature concerning land areas, cultural manifestation (time and type) were

identified and used to predict the occurrence of similar features on shelf areas that were

concurrently exposed. Cultural manifestations were investigated for index artifacts,

environmental use patterns, and particularly land forms favored as habitation sites. An

inventory of known archeological sites, occupied from 55,000 to 3,500 years BP and

covering all three regions, was completed for Preprojectile Point, Paleo-Indian, Archaic, and

Poverty Point periods. To assess the occurrence and distribution of shipwrecks, all

information (maps, charts, logs, and literature descriptions) from colonial settlement to

World War 11(1500 to 1945) was examined. Several criteria based on destinations, home

ports, and routes of ships traversing the Gulf of Mexico were used to select usable records

of shipwreck occurrence. Finally, present methods of site-specific cultural resource surveys

were described and improvements in protocol were recommended.

SIGNIFICANT CONCLUSIONS: Some relict Iandforms can be used as indicators of cultural

resource presence, consequently, once located, they should be considered high probability

areas. Survey techniques included direct observation by diving archaeologists and remote

sensing techniques that search for characteristic signatures. Site-specific surveys should

Cultural Resources 163
employ tight line spacing, and towing speeds should not be more than 6 kn. Records from

archeological surveys should be periodically reviewed by a panel of qualified archaeologists.

More detailed pilot studies are recommended to develop appropriate methodology for

site-specific surveys. There is a shortage of qualified marine archaeologists to meet the

growing survey needs of the offshore oil and gas industry. Two thirds of the total

shipwrecks located occurred within 1 .5 km of the coast; most of these ships sank during

the 1 9th century and the most important group was from the 16th, 1 7th, and 18th

centuries.

STUDY RESULTS: Eleven geomorphic landforms were identified as high probability

cultural resource sites. These 11 discrete site indicators were: quarries, salt domes, springs

(sinkholes), valley margins, natural levees, point bars, bay margins, coastal dune lakes, shell

middens, conical earth mounds, and crescentic an circular villages. These sites were

assigned characteristic signatures based on location, artifacts, fossil remains, and

geomorphology to facilitate their location on the OCS. Culture periods or stages were

classified as: Poverty Point, Late Archaic, Middle Archaic, Early Archaic, Paleo-lndian,

Pre-Fluted Point. The occurrence of site type by cultural stage was investigated, indicating

that: all 11 sites probably occurred during the Poverty Point and Late Archaic periods; all

sites except crescentic and circular villages also occurred during the Middle Archaic period;

and shell middens, conical earth mounds, and crescentic and circular villages did not occur

during the Early Archaic, Paleo-lndian, or Pre-Fluted Point periods. Confirmation of one of

these sites should rely on direct observation and remote sensing techniques. Remote

surveys should include fathometer, subbottom profiler, side-scan sonar, and sampling for

artifacts should employ box, bucket, corer, drag, and grab samples. Still photography and

video tapes should be taken in conjunction with diver observations at verified sites.

An estimated 2,500 to 3,000 shipwrecks were confirmed for the region; about 70% of

these wrecks were from the 1 9th century and the remaining, more historically significant

wrecks were from the 1 6th, 1 7th, and 1 8th centuries. Two thirds of the total number of

wrecks were found within 1 .5 km of the coastline in the northern Gulf of Mexico; another

500 wrecks were located between 1.5 and 10km from the coastline. Other debris,

including military ordnance and discarded materials from fishing and offshore petroleum

activities were found on the shelf. Magnetometers are the best remote sensing instruments

for detecting shipwrecks and submerged debris. Side-scan sonar and subbottom profilers

should augment a shipwreck survey. When not precluded by depth, direct observation by

diving archaeologists is strongly recommended when investigating a wreck site. From the

interpreted ages of relict land forms and shipwreck distributions, a zone map was developed

for the northern Gulf OCS. Zone 1 includes areas of high probability for prehistoric cultural

remains from 12,000 to 3,000 years BP. The seaward limit of Zone 2 delimits the extent of

Paleo-lndian habitation sites. The seaward limit of Zone 3a lies on the maximum low stand

of sea level during the Wisconsin glacial stage. Zone 3b includes a series of banks probably

exposed during the Wisconsin maximum low stand. Zone 4 displays relict shoreline features

in water depths of 90 to 200 m of uncertain age.

STUDY PRODUCT(S): Coastal Environments, Inc. 1977. Cultural Resources Evaluation of

the Northern Gulf of Mexico Continental Shelf. Vol. I, Prehistoric Cultural Resource

Potential. A final report for the U.S. Department of the Interior, National Park Service,

1 64 Cultural Resources
Office of Archeology and Historic Preservation. NTIS No. PB276773/AS. Contract

No. 08550-MU5-40. 361 pp.

Coastal Environments, Inc. 1 977. Cultural Resources Evaluation of the Northern Gulf of

Mexico Continental Shelf. Vol. II, Historical Cultural Resources. A final report for the U.S.

Department of the Interior, National Park Service, Office of Archeology and Historical

Preservation. NTIS No. PB2767741AS. Contract No. 08550-MU5-40. 171 pp.

Coastal Environments, Inc. 1977. Cultural Resources Evaluation of the Northern Gulf of

Mexico Continental Shelf. Vol. Ill, Maps. A final report for the U.S. Department of the

Interior, National Park Service, Office of Archeology and Historic Preservation. NTIS No.

PB2868741AS. Contract No. 08550-MU5-40.

STUDY TITLE: Gulf of Mexico OCS Cultural Resources Sensitivity Zone Mapping.

COMPLETION DATE OF REPORT: 1977.

CUMULATIVE PROJECT COST: $500,000.

KEY WORDS: Eastern Gulf; Central Gulf; Western Gulf; cultural resources; archeology;

geology; shipwrecks.

Cultural Resources 165
SIATUT! UI(.(S 0 50 00 - r' KIL0MiTt$ 0 50 00 00 200 C NTRAL ULF OF MEXICO REGION TROPIC OF CANCtR STUDY AREA FOR SHIPWRECK SITE COMPILATION AND CULTURAL RESOURCES EVALUATION OF NORTHERN GULF OF MEXICO
INFORMATION MANAGEMENT

Since the inception of the Environmental Studies Program, more than $136 million has

been invested in the Gulf of Mexico for obtaining environmental data and information

necessary for Federal oil and gas management activities. This considerable body of

study reports available at present occupies some 60 feet of shelf space, encompassing

literally millions of pieces of data. Information management occurs at several different

levels; information development occurs at the synthesis level, where separate

comparisons, presentations, and analyses from a broad region are integrated into broad

characterizations; at the management tool level, source level and synthesis level

technical information is integrated with law, regulations, and policy to produce the

everyday working documents of the agency.

Information Management 167
REPORT TITLE: Bibliography of Benthic Studies in the Coastal and Estuarine Areas of

Florida.

MMS PUBLICATION NUMBER: Contract No.14-12-0001-29037.

APPLICABLE PLANNING AREA(S): South Atlantic; Eastern Gulf of Mexico.

STUDY TITLE: Review and Annotated Bibliography of Benthic Studies in the Coastal and

Estuarine Areas of Florida.

COMPLETION DATE OF REPORT: August 1984.

CUMULATIVE PROJECT COST: $9,981.

KEY WORDS: South Atlantic; Eastern Gulf; Florida; benthos; bibliography; estuarine;

sediment; algae; macrophytes; coral reef; macrofauna; meiofauna; fish; intertidal; subtidal; pollution; impacts.

BACKGROUND: Benthic ecology, the study of bottom dwelling flora and fauna, has

flourished in the State of Florida in the last two decades. The abundance and diversity of benthic habitats in and around the State and the pressures of water use and waterfront

development have both contributed to the advancement of research in this field. Almost

75% of the research on benthic habitats and organisms conducted in the last decade has

been done to either evaluate or mitigate an environmental problem. The State of Florida's Department of Environmental Regulation has enacted a "biological integrity" rule which

utilizes the relative health of benthic communities as a criterion for regulating dredge and fill activities. Seagrasses, intertidal wetlands, oyster reefs, and hard-bottom patch reefs are

routinely considered as valuable benthic habitats, and activities in these habitats are

stringently regulated by local, State, and Federal agencies. Soft-bottom habitats and their

fauna, although studied more extensively, do not enjoy the same protection, but are used as

excellent indicators of various types of pollution. The utility of benthic communities in the

assessment of various types of pollution is definitely recognized; time factors and the lack

of ease in obtaining historical information have often hampered utilization of benthic data

for pollution assessment. Over 70% of benthic information from Florida is in the form of

technical reports and unpublished material. This report provides a compilation of all published and most unpublished literature of benthic studies in coastal and estuarine waters

of Florida through 1 982. Project funding support was provided jointly by the Florida Sea Grant College, Minerals Management Service, and Mote Marine Laboratory. Partial funding

support for publication was provided by the State of Florida Department of Environmental Regulation, Office of Coastal Management, and State of Florida Department of Natural Resources, Bureau of Marine Research.

OBJECTIVES: (1) To provide an annotated bibliography of papers and reports on benthic studies relevant to Florida; (2) to provide a compilation of methodological references; and

(3) to provide citations of taxonomic descriptions and identification keys which are relevant

to marine and esruarine benthos of Florida.

Information Management 169
DESCRIPTION: This bibliography includes all available literature on the benthos (and its

environment), except freshwater benthos, through the year 1982. Study geographic limits

were: all of the continental shelves bordering Florida (Atlantic and Gulf of Mexico) and all

estuaries and bays within Florida. All benthic components (sediments, algae, macrophytes,

coral reefs, macrofauna, meiofauna, microfauna, and demersal fishes) were included in the

bibliography. Both intertidal and subtidal environments were included. Literature search

was accomplished by the following means: (1) computer searches on various biological and

earth science data bases (Aquaculture, Aqualine, Aquatic Sciences and Fisheries Abstracts,

Biosis Previews, CA Search, Comprehensive Dissertation Index, Enviroline, NTIS, Oceanic

Abstracts, Pollution Index, Scisearch, SSIE, Current Research); (2) search of individuals',

universities', and agencies' libraries; (3) personal and letter contact with private

organizations and individuals; and (4) interlibrary loans. This document is divided into four

parts. Part A provides a general introduction to the report with a brief review and summary

of existing benthic studies in coastal and estuarine areas of Florida. Part B provides an

annotated bibliography of published and unpublished reports relevant to Florida. Part C

provides a selected compilation of methodological references considered to be useful for

benthic studies. Part D Provides citations of taxonomic descriptions and identification keys

which are relevant to Florida marine and estuarine benthos.

SIGNIFICANT CONCLUSIONS: Benthic studies in Florida have generally addressed the

following aspects of the science: fisheries, pollution, baseline studies, species-specific

studies, checklists, and method studies. Bays, estuaries, and embayments have been

studied for their importance as nursery areas. More emphasis needs to be placed on

methodology in sample collection and analysis to enhance consistency and scientific

credibility of benthic studies. Available taxonomic references are scattered in the literature;

there is a need for well organized taxonomic guides.

STUDY RESULTS: Benthic studies in Florida have generally emphasized benthic fisheries,

pollution effects, baseline studies, species-specific studies, checklists, or methodological

studies. Several studies have concentrated on benthic fisheries in Florida, especially on pink

shrimp, oysters, blue crabs, stone crabs, and clams. Many studies have assessed and

evaluated pollution effects, especially from power plants, dredge and fill projects, sewage

discharges, and stormwater runoff. Other types of pollution have also been studied, such

as petroleum, pesticides, metal, and pulp mill effluents. Several background

characterizations or baseline studies have been sponsored in anticipation of development

activities. Numerous species-specific studies have been conducted primarily as research

theses or dissertations of Florida universities. Several checklists, field guides, and

taxonomic descriptions have been prepared. Many methodological studies have been

conducted, especially as they relate to construction. Bays, estuaries, and embayments have

been studied intensively for their importance as nursery areas particularly Tampa, Biscayne,

Escambia, and Apalachicola Bays. Charlotte Harbor is the least studied major estuary in

Florida. Studies are generally concentrated in areas where universities, marine laboratories,

or National Parks exist, or where development pressures are heavy.

Utilizing adequate methodology in sample collection is probably the most important factor in

scientific credibility of a study. Many studies did not adequately consider replication, sieve

size, taxonomic grouping, statistical analyses, physical factors, and substrate

characteristics. Many community-type studies did not contain adequate discussions of life

1 70 Information Management
history characteristics and/or ecological roles of even the dominant species. The

compilation of methodological references is included to provide consistency to benthic

studies.

Taxonomy adequacy is important in benthic studies; ecological surveys need accurate

taxonomy for a reasonable assessment of the environment. Available taxonomic references

are scattered in the literature and need to be organized into guides. Few taxonomists are

practicing in Florida; therefore, few taxonomic studies of Florida estuarine and coastal fauna

are being conducted.

STUDY PRODUCT(S): Mahadevan, S., J. Sprinkel, D. Heatwole, and D. H. Wooding.

1 984. A Review and Annotated Bibliography of Benthic Studies in the Coastal and

Estuarine Areas of Florida. A final report by Mote Marine Laboratory for the U.S.

Department of the Interior, Minerals Management Service, Washington, D.C. Florida Sea

Grant College Report No. 66. Contract No.14-12-0001-29O37. 576 pp.

STUDY TITLE: Review and Annotated Bibliography of Benthic Studies in the Coastal and

Estuarine Areas of Florida.

Map #29037 Unavailable.

Information Management 171
REPORT TITLE: The Mississippi, Alabama, Florida, Outer Continental Shelf Baseline

Environmental Survey MAFLA 1977/1978.

MMS PUBLICATION NUMBER: Contract No. AA550-CT7-34.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico.

BACKGROUND: In 1 974, the U.S. Department of the Interior initiated comprehensive

marine environmental surveys of the Outer Continental Shelf (OCS) off Mississippi,

Alabama, and Florida (MAFLA). Data were collected for three years to establish a baseline

from which to evaluate effects of oil and gas activities in the MAFLA region. This report

comprises the final year (1977/1 978) results and overall program synthesis.

OBJECTIVES: (1) To determine concentrations of high molecular weight hydrocarbons and

selected trace metals in the water column, sediments, and selected benthic macrofauna;

(2) to continue seasonal studies of benthic infauna, meiofauna, and forarninifera; (3) to

continue histopathological studies to determine tissue conditions of selected benthic

macrofauna; and (4) to collect samples and conduct analysis supportive of benchmark data

interpretation.

DESCRIPTION: The study area was the MAFLA OCS in the eastern Gulf of Mexico,

bounded by 81 °30 to 89°W long, and 25°30' and 30°15N lat. Four cruises were carried

out during 1977/1978: August-September 1977, October-November 1977, and February

1978. Sample depths ranged from 10 to 200 m.

Temperature and salinity were recorded using salinity/temperature/depth systems, water

samplers, and reversing thermometers. Transmissorneters and photometers were used to

detect water clarity and light penetration. A box corer (21.3 x 30.5 x 43.2 cm) was used

to obtain sediment samples 600 cm2 in surface area and of 40 cm depth. A 10-rn

semi-balloon trawl and a rectangular dredge (97 cm x 41 cm) were used to collect

rnacroepifauna and demersal fishes. Forty-nine box core stations and 1 7 dredge and trawl

samples were taken along eight transects. Sediment samples were analyzed for grain size,

percent carbonate, clay mineralogy, total organic carbon (TOC), adenosine triphosphate,

hydrocarbons, trace metals, foraminifera, meiofauna, and macrofauna. Macroepifauna,

zooplankton, and demersal fishes were identified and then analyzed for hydrocarbons and

trace metals [with and without barium (Ba) and vanadium (V)J using gas chromatography,

atomic absorption spectrophotometry, and neutron activation analysis, respectively. Water

samples were analyzed for suspended sediment mineralogy, particulates, trace metals (with

and without Ba and V), particulate hydrocarbons, dissolved hydrocarbons, particulate

organic carbon, dissolved organic carbon, and salinity. Tissue samples were analyzed from

various macroepifaunal groups using standard histological techniques.

Data from the MAFLA surveys were subjected to various univariate and multivariate

statistical analyses. Descriptive statistics were obtained, then multivariate techniques

(cluster analysis, principal components analysis, stepwise discriminant analysis, and

canonical analysis) were used. A suite of resemblance measures and diversity indices were

used to determine species associations and community parameters.

Information Management 1 73
SIGNIFICANT CONCLUSIONS: Ecological, histophathological, and histochemical evidence

indicated that the MAFLA area was pristine and healthy. In many parts of the MAFLA

region, sediments were essentially free of any detectable petrogenic or anthropogenic

hydrocarbons, and the water column showed only biogenic sources. Sediment and water

column trace metal levels were low and reflected animal tissue levels.

STUDY RESULTS: The Mississippi River and Loop Current are major oceanographic

influences in the MAFLA area. The Loop current is variable, causes short-term changes in

vertical temperatures, and tranports tropical larvae and trace metals into the area. The

water column is often stratified in the northern portion of the study area and more variable

over the west Florida shelf. The shelf off Mississippi and Alabama is dominated by fine

sediments with low carbonate content. The Mississippi River is the major source of these

fine sediments. The west Florida shelf has little active sedimentation with predominantly

carbonate sand offshore and quartz inshore. The two sediments intermix in the vicinity of

Cape San Bias.

MAFLA area sediments were grouped into three geochemical provinces based upon

hydrocarbon source. No evidence of anthropogenic or petrogenic hydrocarbons was found

in nearshore area (<50 m) of the west Florida shelf. Deeper sections were characterized by

accumulations of fine sediments and high TOC. The Alabama-Mississippi shelf showed

traces of petrogenic content.

Trace metal pollution was not detected for any station. Metals analyzed were

representative of possible pollutants associated with crude oil and offshore construction

activities. Sediment trace metals increased offshore and to the northwest. Regression

analysis indicated that the effects of independent variables on concentrating trace metals

was % fines > TOC > CaCO3. Trace metals in dernersal fishes were related to bioavailable

trace metals in sediments. Dusky flounder (Syacium papilosum) had trace metal

concentrations related to ambient sediment concentrations. Generally, trace metal values

were low in the water column, sediments, and animal tissues.

Foraminiferans increased in abundance offshore and to the north resulting in a positive

correlation with fine sediments. Sources of stress were apparently natural (salinity,

temperature, or sedimentology). Meiofauna exhibited an extremely patchy spatial and

seasonal distribution throughout the MAFLA area. Abundances were moderately correlated

with sediments. Taxonomic problems made meiofauna poor indicators of environmental

stress. Species diversity and density of infaunal species (60% polychaetes) decreased

offshore and to the west. Macroepifauna also followed the pattern of decreasing diversity

in an offshore direction. A total of 292 fish species were collected. Pattern analyses

revealed fish species groups to be aligned along the 40-rn, 100-rn, and 200-rn isobaths.

About 400 taxa of zooplankton were recorded from the MAFLA area. Oceanic, slope, and

shelf species interchanged on the west Florida shelf but no coastal species were collected.

No occurrences of pathology were found. The MAFLA area was considered generally

healthy and an excellent region for conducting monitoring studies before, during, and after

oil and gas exploration and development activities.

1 74 Information Management
STUDY PRODUCT(S): Dames and Moore. 1979. The Mississippi, Alabama, Florida, Outer

Continental Shelf Baseline Environmental Survey MAFLA 1977/1978. A final report to the

U.S. Department of the Interior, Bureau of Land Management Gulf of Mexico OCS Office,

New Orleans, LA. Vol. IA (Program Sythesis Report) - NTIS No. PB294-277: Vol. lB

(Executive Summary Report) - NTIS No. PB294-228; Vol. IlA (Compendium of Work

Element Reports) - NTIS No. PB299-686; Vol. IIB (Compendium of Work Element Reports) -

NTIS PB299-687. Contract No. AA550-CT7-34.

STUDY TITLE: Eastern Gulf of Mexico OCS Benchmark Study.

COMPLETION DATE OF REPORT: January 1979.

CUMULATIVE PROJECT COST: $3,783,010.

KEY WORDS: Eastern Gulf; Mississippi; Alabama; Florida; baseline; benchmark; biology;

hydrocarbons; trace metals; water column; sediment; tissue; macrofauna; meiofauna;

histopathology; hydrography; fish; epifauna; Loop Current; shelf; seasonality; diversity.

Information Management 1 75
'I. It. UOAN CITY 0ULP O MIXICO E0I0N CAITCIN ,,iIPESAC.A'"t I I - I 14 PANAMA . ITY 1 1 I PRIMARY STATION LOCATIONS FOR THE EASTERN GULF OF MEXICO OCS BENCH MARK STUDY. FY 1977.0 CI 10 71 100 KIL

0 CI 10 75 

-J 
REPORT TITLE: Taxonomic Guide to the Polychaetes of the Northern Gulf of Mexico.

MMS PUBLICATION NUMBER: Contract No. 14-12-0001-29091.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico;

Western Gulf of Mexico.

BACKGROUND: Biological baseline studies carried out on the Gulf of Mexico Outer

Continental Shelf (OCS) routinely include infaunal samples taken from soft substrates.

Polychaete worms usually predominate these benthic samples, however, taxonomic

inconsistencies preclude the incorporation of polychaete assemblages in meaningful

ecological evaluations. When proper identifications allow, polychaetes are valuable as

indicators of distinct faunal assemblages or environmental stress. Hence, polychaetes are of

great interest to environmental managers. Recognizing the taxonomic consistency problem,

the Bureau of Land Management (BLM) funded a study to standardize all polychaete

identifications from major BLM OCS studies conducted in the northern Gulf of Mexico to

develop a general polychaete identification guide. The study was expanded and completed

under funding from the Minerals Management Service (MMS).

OBJECTIVES: (1) To provide taxonornic standardization and develop an identification

guide for polychaetes collected during major BLM/MMS projects from the northern Gulf of

Mexico OCS.

DESCRIPTION: Polychaete specimens were secured from voucher collections of the

following BLM/MMS studies: South Texas Outer Continental Shelf Study (STOCS),

Mississippi-Alabama-Florida Study (MAFLA), Ecological Investigations of Petroleum Platforms

in the Central Gulf (CTGLF), IXTOC Oil Spill Study (IXTOC), and Southwest Florida Shelf

Ecosystems Study (SOFLA). A breakdown of polychaete taxa and families initially reported

by each study is as follows: MAFLA: 586 taxa, 58 families; SOFLA 250 taxa, 46 families;

CTGLF 158 taxa, 56 families; STOCS 312 taxa, 44 families; IXTOC 103 taxa, 36 families.

Geographical coverage of these studies includes the continental shelf of the northern Gulf of

Mexico from Brownsville, Texas to the Florida Keys and offshore to the 200-rn isobath.

Inner, middle, and outer shelf water depths were covered during the efforts of most

studies. Sediment type reported for each study generally reflected geographic location; the

eastern Gulf (MAFLA and SOFLA) consisted mostly of medium to coarse grained sands while

the central and western Gulf (CTGLF, IXTOC, and STOCS) sediments were mostly finer

sands, silts, and clays. Initially, voucher specimens obtained from the contractors of

individual studies were sorted to family then re-examined by taxonomists using various

microscopes and mounting techniques. Following examination and detailed taxonomic

description of the material, representative specimens were deposited in the National

Museum of Natural History, Smithsonian Institution, Washington, D.C. and any additional

material was kept in the museum of Barry A. Vittor & Associates, Inc.

SIGNIFICANT CONCLUSIONS: A total of 593 polychaete taxa were recognized from the

collections; 41 % were new to science. The guide is an accumulation of diagnostic keys,

based on external features (i.e., setae and parapodia), for the identification of polychaetes

from soft bottom areas in the northern Gulf of Mexico. Numerous inconsistencies were

Information Management 177
discovered during this project that would hinder ecological or zoogeographical analyses.

Numerous animal-sediment relationships were also discerned during the course of the study.

STUDY RESULTS: The efforts of this study resulted in identification of 593 species in 228

general and 59 families. Forty one percent of the examined polychaetes were new to

science or previously undescribed. Numerous misidentifications were uncovered which will

improve geographical and ecological analyses. The identification guide, assembled using the

reexamined material, is arranged by polychaete family, into chapters. The chapters,

arranged in phylogenetic order, each treat a single family and provide diagnostic characters

of the family, biological notes on the family followed by a taxonomic treatment. The

taxonomic section of each chapter includes generic keys, generic diagnoses, species keys,

and species descriptions. Biological notes include characteristic life history, feeding

strategy, reproduction, substrate preference, tube construction, locomotion, behavior,

commensalism, parasitism, and larval development are given when possible. Each species

description gives a list of BLM/MMS-OCS and any supplementary material examined, a

synonymy and ecological and geographical information when available. Figures are given

showing distribution of species in the northern Gulf of Mexico and detailed drawings of

characters useful in the identification of particular species are also provided. In addition,

figures are given showing the distribution of species in the northern Gulf of Mexico.

STUDY PRODUCT(S): Uebelacker, J. M. and P. G. Johnson. 1984. Taxonomic Guide to

the Polychaetes of the Northern Gulf of Mexico. A final report by Barry A. Vittor &

Associates for the U.S. Department of the Interior, Minerals Management Service Gulf of

Mexico OCS Region, Metairie, LA. Vol. I - NTIS No. PB85-1 50752; Vol. II - NTIS No.

PB85-1 50761; Vol. Ill - NTIS No. PB85-1 50779; Vol. IV - NTIS No. PB85-1 50787; Vol. V - NTIS No. PB85-1 50795; Vol. VI - NTIS No. PB85-1 50803; Vol. VII - NTIS No.

PB85-150811. Contract No. 14-12-0001-29091. 7 Vols.

STUDY TITLE: Gulf of Mexico Polychaeta Standardization Study.

COMPLETION DATE OF REPORT: 1984.

CUMULATIVE PROJECT COST: $257,602.

KEY WORDS: Eastern Gulf; Central Gulf; Western Gulf; Texas; Mississippi; Alabama;

Florida; Florida Keys; biology; Southwest Florida Shelf; polychaete; standardization;

voucher; specimens; shelf; sediment; diagnostic key; life history.

1 78 Information Management
copue CHI*TI GAL VEeTON I, MOSILE PENSACOLA GIJLFPORT I 2 PANAMA CtlV. 

25° 0 o -00 0 00000 00 00 WESTERN Ii I 000000 0000 0 0 GD 00 CENTRAL 0 0 0 EASTERN GULF OF MEXICO REGION STATUTE MILES 0 50 00 - ---------TROPIC OF CANCER KILOMr1cpt 0 50 lOG ISO 100 

INFAUNAL STATION LOCATIONS FROM U.S. DEPARTMENT OF THE INTERIOR OUTER CONTINENTAL SHELF STUDIES USED 

GULF OF MEXICO POL.YCHAETA STANDARDIZATION STUDY.
REPORT TITLE: Mississippi-Alabama Shelf Pinnacle Trend Habitat Mapping Study. Final

Report.

MMS PUBLICATION NUMBER: Contract No. 14-35-0001-30494.

APPLICABLE PLANNING AREA(S): Eastern Gulf of Mexico; Central Gulf of Mexico.

BACKGROUND: Significant topographic features were identified during the MississippiAlabama Marine Ecosystem Study performed by Texas A&M University (1987-1 990) in

adjacent areas west of those where geophysical mapping occurred. As a result of these

findings, the MMS determined a need for further geophysical mapping and biological

characterizations in this western area.

OBJECTIVES: (1) To geophysically survey and map significant topographic features and

substrate trends located within the study area; and (2) to characterize the biological

communities associated with these topographic features.

DESCRIPTION: Data collection was divided into two separate field sampling efforts. The

first field effort (Survey 1) was planned and conducted with the intent of collecting

geophysical data (i.e., side-scan sonar and subbottom profiler data) throughout the entire

study area. This collection procedure required 100% coverage of the seafloor within the

study area using side-scan sonar to locate and plot significant topographic features.

Following analysis of the geophysical data and the development of draft features and

substrate maps, a second field effort took place (Survey 2). The purpose of Survey 2 was

to verify the side-scan sonar target interpretations and to characterize the biological

communities associated with these previously mapped features. A remotely operated

vehicle (ROV) equipped with video and still cameras was utilized to conduct the biological

characterizations.

The geophysical characterization survey (Survey 1) was conducted between 11 September

and 10 October 1 990. A total of 92 survey lines, including 86 east-west lines and 6 northsouth tie lines, were investigated using side-scan sonar and subbottom profiler. Bathymetric

data was collected simultaneously with the geophysical data.

The biological characterization survey (Survey 2) was conducted between 11 October and 7

November 1991. Using the data collected during Survey 1, significant and representative

topographical features and substrates were selected and prioritized for investigation.

SIGNIFICANT CONCLUSIONS: Detailed maps of hard bottom, pinnacles, prominences, and

sediment reflectivity were produced based on an OCS lease block grid. The presence of

extensive pinnacle complexes south and southwest of the previously mapped areas of the

Mississippi-Alabama shelf were confirmed and biological data on the community structure of

organisms inhabitating that environment were collected. Two distinct areas of hard bottom

and pinnacle features were noted which probably show differing geologic origins.

STUDY RESULTS: Two physiographically different areas of the Mississippi-Alabama shelf

and slope were surveyed under this research effort. A large portion of the study area was

above the shelf break which is generally considered to be the 75 m (245 ft) isobath in this

Information Management 181
part of the Gulf. The Mississippi-Alabama shelf is divided into two sedimentary provinces.

In the eastern province there is a thin, well-sorted layer of fine- to medium-grained quartzose

sand transported to the shelf by rivers during the Pleistocene and early Holocene (1 .6 million

to 100,00 YBP). To the west, the shelf in this area is covered by a layer of fine silts, sands

and clays associated with Mississippi River disposition. The present study straddles these

provinces. In the east, sediment reflectivity is high and penetration poor. Toward the west

where the silts and clays of the old St. Bernard Delta overlap the quartzose sediments,

subbottom profiler penetration increases and bottom reflectivity drops. Buried channels are

also evident in this area. A series of low-relief hard bottom features are seen at or near the

shelf break in the eastern portion of the study area which appear similar to inner shelf hard

bottom features described from the Alabama shelf.

Beyond the shelf break on the upper slope (75 to 400 m; 246 to 1 ,300 ft), two major areas

of hard bottom, shelf-edge prominences were mapped. These included (1) an area of large

pinnacle development between the 80 and 90 m (260 to 295 ft) bathymetric contours

termed Area 1; and (2) an area of low relief hard bottom and small pinnacles or mound type

features between the 110 and 130 m (360 to 426 ft) bathymetric contours termed Area 2.

Pinnacles observed in the first area were large features which were seen singly or in clumps

often reaching a height of 20 m (60 ft) or more above the seafloor. These features were

oriented in a northwest to southwest direction and were surrounded by a sand bottom. The

features seen in Area 2 were different in appearance on the geophysical record. Area 2

features were smaller in overall height than Area 1 features, although some individual

features reached heights similar to the smaller features seen in Area 1. Small mound-like

features were also evident which were much wider and did not show the same subbottom

characteristics as pinnacle features, although they reached the same height above bottom.

In addition, the general substrate in this deeper area appeared to be continuous low-relief

hard bottom.

A total of 19 ROV dives were conducted at separate locations during the biological survey.

Nine of these dives were in the major pinnacle area described above (Area 1), and three

dives were in shallow water areas on the Mississippi-Alabama shelf above the 75 m (246 ft)

depth contour. Biological communities occurring on the major pinnacles were dominated by

tropical and subtropical suspension-feeding invertebrates. Communities were similar on all

features investigated, but very subtle differences were noted based on individual pinnacle

size. Generally, the horizontal surfaces in the upper areas of the pinnacle supported the

most diverse and abundant communities. Near the base of a feature, the associated

biological community was reduced both in numbers of individuals and in terms of

community diversity.

No true hard bottom was seen at any of the three sites investigated above the 75 m (246

ft) contour, suggesting that these features were artifacts of side-scan sonar interpretation.

Hard bottom and similar signatures were removed from the final map products produced. If

these low-relief features were present and were subsequently covered by shifting sand, it is

very likely that the epibiota and fishes associated with them would be minimal. Further

investigations are needed to verify the possible hard bottom signatures seen in other upper

shelf areas covered by this survey.

182 Information Management
STUDY PRODUCT(S): Continental Shelf Associates, Inc. 1992. Mississippi-Alabama Shelf

Pinnacle Trend Habitat Mapping Study. Final Report. A final report for the U.S. Department

of the Interior, Minerals Management Service, Gulf of Mexico OCS Region, New Orleans, LA.

OCS Study/MMS 92-0026. Contract No. 14-35-0001-30494. 75 pp + app.

A two-part map set (scale: 1: 1 20,000) was also prepared under this study effort.

STUDY TITLE: Mississippi-Alabama Shelf Pinnacle Trend Habitat Mapping Study.

COMPLETION DATE OF REPORT: August 1992.

CUMULATIVE PROJECT COST: $444,827.

KEY WORDS: Eastern Gulf; Central Gulf; geology; biology; pinnacles; prominences;

survey; characterization; maps; abundance; diversity; community; hard bottom, ROV; sidescan sonar; substrate mapping; habitat mapping.

Information Management i 83
94 ( 92 91 90 MISSISSIPPI CE NT IA I GULF OF MEXICO UEGION LOUISIANA ' - --- MONGAN CITS ..ALAD

25 50 75 

2S 50 75 00 KILOMETE

AFIEA SUflVEYED DUllING THE MISStSSIPPI-AI ABAMA SHELF PINNACLE TREND HABITAT MAPPING STUDY
The Department of the Interior Mission

As the Nation's principal conservation agency, the Department of the Interior has responsibility

for most of our nationally owned public lands and natural resources. This includes fostering

sound use of our land and water resources; protecting our fish, wildlife, and biological diversity;

preserving the environmental and cultural values of our national parks and historical places; and

providing for the enjoyment of life through outdoor recreation. The Department assesses our

energy and mineral resources and works to ensure that their development is in the best interests

of all our people by encouraging stewardship and citizen participation in their care. The

Department also has a major responsibility for American Indian reservation communities and for

people who live in island territories under U.S. administration.

The Minerals Management Service Mission

As a bureau of the Department of the Interior, the Minerals Management Service's (MMS) primary

responsibilities are to manage the mineral resources located on the Nation's Outer Continental

Shelf (OCS), collect revenue from the Federal OCS and onshore Federal and Indian lands, and

distribute those revenues.

Moreover, in working to meet its responsibilities, the Offshore Minerals Management Program

administers the OCS competitive leasing program and oversees the safe and environmentally

sound exploration and production of our Nation's offshore natural gas, oil and other mineral

resources. The MMS Royalty Management Program meets its responsibilities by ensuring the

efficient, timely and accurate collection and disbursement of revenue from mineral leasing and

production due to Indian tribes and allottees, States and the U.S. Treasury.

The MMS strives to fulfill its responsibilities through the general guiding principles of: (1) being

responsive to the public's concerns and interests by maintaining a dialogue with all potentially

affected parties and (2) carrying out its programs with an emphasis on working to enhance the

quality of life for all Americans by lending MMS assistance and expertise to economic

development and environmental protection.
Minerals Management Service

Gulf of Mexico OCS Region

U.S. Deportment of the Interior UE3J .flcJJ

Managing America's offshore energy

resources

Protecting America's coastal

and marine environments