ACCESS NUMBER: 30991 

STUDY TITLE: Deepwater Program: Northern Gulf of Mexico Continental Slope 

Habitats and Benthic Ecology 

REPORT TITLE: Deepwater Program: Northern Gulf of Mexico Continental Slope 

Habitats and Benthic Ecology, Interim Report, Year 1 

CONTRACT NUMBER: 1435-01-99-CT-30991 

SPONSORING OCS REGION: Gulf of Mexico, OCS 

APPLICABLE PLANNING AREA: Northern Gulf of Mexico 

FISCAL YEARS OF THE PROJECT: 2000, 2001, 2002, 2003 

COMPLETION DATE OF REPORT: December 2001 

COSTS: 2000: $1,253,359 ; 2001: $1,178, 201 ; 2002: 1,105,657; 2003: $651,490; 

CUMULATIVE PROJECT COST; $4,188,707 

PROJECT MANAGERS: Dr. Gilbert T. Rowe, Program Manager and Dr. Mahlon C. 

Kennicutt II, Deputy Program Manager 

AFFILIATION: Texas A&M University 

ADDRESS: Texas A&M University, College Station, Texas 77843 

PRINCIPAL INVESTIGATORS*: Gary Wolff, Jody Deming, Ian MacDonald, Paul 

Montagna, Richard Haedrich, Benny Galloway, John Morse, William Bryant, and Worth 

Nowlin 

KEYWORDS: Benthic Ecology, Northern Gulf of Mexico, Contaminants, Microbiota, 

Foraminifera, Meiofauna, Macrofauna, Demersal Fishes, Megafauna, Physical 

Oceanography, Hydrography, Geological Oceanography, Biogeochemistry, 

Geochemistry, Ecosystem Health, Ecosystem Modeling, Habitats, Zonation, and 

Carbon Limitation. 

BACKGROUND: Increasing exploration and exploitation of fossil hydrocarbon 

resources in the deep-sea prompted the Minerals Management Service of the U.S. 

Department of the Interior to support an investigation of the structure and function of the 

assemblages of organisms that live in association with the sea floor in the deep-sea. 

The program, Deep Gulf of Mexico Benthos or DGoMB, is studying the northern Gulf of 

Mexico (GOM) continental slope from water depths of 300 meters on the upper 

continental slope out to greater than 3,000 meters water depth seaward of the base of 

the Sigsbee and Florida Escarpments. The study is focused on areas that are the most 

likely targets of future resource exploration and exploitation. However, to develop a 

Gulf-wide perspective of deep-sea communities, sampling in areas beyond those 
ACCESS NUMBER: 30991 

thought to be potential areas for exploration has been included in the study design. A 

major enhancement in the program is the extension of the transects onto the abyssal 

plain of the central Gulf of Mexico through collaborative studies with Mexican scientists. 

This additional work effort will allow assessment of benthic community structure and 

function throughout the basin by sampling the deepest habitats in the region. 

The program is designed to gain a better ability to predict variations in the structure and 

function of animal assemblages in relation to water depth, geographic location, time and 

overlying water mass. Biological studies are integrated with measurements of physical 

and chemical hydrographic parameters, sediment geochemical properties and 

geological characteristics that are known to influence benthic community distributions 

and dynamics. Eleven (11) hypotheses are being tested on the basis of measures of 

benthic community structure. 

OBJECTIVES: The goals of the program are to: 

1. determine in greater detail the composition and structure of slope bottom biological 

communities and to infer relationships between biological patterns and major 

controlling processes and 

2. characterize the area as to its present “health” and function and compare and 

contrast the region with similar oceanic regions. 

Specific program objectives are to: 

1. improve a conceptual model that served as the guide for the design and overall 

conduct of the study and to test specific hypotheses related to the models; 

2. compile and synthesize data from existing databases and on-going programs to 

interpret new results; 

3. conduct field collections to describe the distribution and structure of benthic 

communities on the continental slope of the GOM and to elucidate the functional 

interactions among them in known environmental settings; 

4. characterize the hydrographic structure and measure the dissolved and particulate 

water column nutrient concentrations, primary productivity, and chlorophyll a at the 

study sites; 

5. characterize the sediments at the study sites including grain size and hydrocarbon, 

metal, carbonate, and organic carbon concentrations; 

6. characterize the basic attributes of the benthic microbiota and biomass at the study 

sites; 

7. characterize the soft-bottom macro- and megafauna at the study sites; 

8. relate variations in benthic biota patterns to sedimentary processes and to the 

chemical and physical setting; 

9. define basic levels of animal and bacterial activity and production and describe 

interactions between and among benthic biota, the several ecological/biological 

compartments, and the abiotic environment; and 

10. compare and contrast the GOM benthic marine environment and communities with 

those in other basins of similar depth ranges and oceanic settings. 
ACCESS NUMBER: 30991 

DESCRIPTION: The program is to be conducted over a 48-month period of 

performance. Major oceanographic cruises are to be conducted one in each of the first 

two years of the program and two in the third year. The final year of the program will be 

dedicated to completing sample analyses begun in the first three years, data 

management and interpretation, model refinement, and production of the Synthesis 

Report. The field surveys will document the biota, the abiotic character of the slope and 

the important biotic and abiotic forcing factors. Station selection criteria included 

consideration of anticipated zonation, water depth, distance from shore, abiotic 

variables, physiography and topography, geochemical environment, anthropogenic 

effects, and present and future leasing trends. 

The program consists of four tasks: 

TASK 1 - Re-examination of Existing Data and Field Study Design 

TASK 2 - Field Sampling 

TASK 3 - Sample and Data Processing and Analysis 

TASK 4 - Data Interpretation, Synthesis and Reporting 

SIGNIFICANT CONCLUSIONS: Due to the preliminary nature of this first interim report 

significant conclusions have not yet been drawn. This report provides a detailed 

description of a deep-sea community model, the field and laboratory methods, and the 

program design assumptions and elements. Work is progressing on schedule. 

STUDY RESULTS: Due to the preliminary nature of this first interim report no 

significant study results are yet available. Preliminary data is presented were 

appropriate. 

STUDY PRODUCTS: This program will produce 48 Monthly Progress Reports, Two 

Interim Reports, One Final Synthesis Report, Multiple Peer Reviewed Publications, Four 

ITM Sessions, 6 Cruise Plans, 6 Cruise Reports, and Two Planning Meeting Reports. 

*P.I.’s affiliation may be different than that listed for Project Manager(s). 
ACCES

Study Area - The Northern Gulf of Mexico