MMS ENVIRONMENTAL STUDIES PROGRAM:  ONGOING STUDIES

MMS OCS Region:

Gulf of Mexico

Planning Area:

Gulfwide

Title:

Deepwater Program:  Northern Gulf of Mexico Continental Slope Habitats and Benthic Ecology Study (GM-99-02)

Total Cost:  $5,325,713

Period of Performance:  FY 1999-2006

Conducting Organization:

The Texas A&M University System

MMS Contact:

Gregory S. Boland

Description:

Background:  Numerous descriptive studies of the continental shelf are available. In contrast, the topography, geology, geophysics, currents, chemistry, and biota of the continental slope are somewhat less well known. An MMS-sponsored study, the Northern Gulf of Mexico Continental Slope Study (NGOMCS), concentrated on the geologic features, water masses, chemistry, and biologic communities of the northern Gulf from the 300-m isobath to abyssal depths. Largely as a result of that study, the Gulf of Mexico is regarded as a well-sampled and geographically well-defined deep-sea system. The relatively old (~14 years) NGOMCS investigations were designed and conducted without knowledge of chemosynthetic communities and seafloor geological processes, and without access to new technologies, methods, and instruments now available. MMS has also funded two multidisciplinary chemosynthetic communities’ studies. The MMS awarded an ongoing study, "A Management Overview for Resource Development in Continental Slope Habitats", as a part of the Coastal Marine Institute (CMI). This study is reinvestigating the habitats and communities of the continental slope with a more modern understanding of its environmental (especially geological and geochemical) complexity. The oil and gas industry is moving into deeper and deeper water and in recent years, has leased tracts in depths greater than 3,000-m. This has placed archibenthal and deep pelagic communities within the range of any potentially adverse environmental effects. Over the past two decades, biological and geological investigations on the northern Gulf of Mexico continental slope have changed our thinking on the nature of deep-sea benthic biogeochemical processes and animal community structure. Discoveries of chemosynthetic communities and their potential for benthic primary productivity, a better understanding of deep geological processes and its resulting topographic and chemical complexity, and other revelations now suggest that the deep Gulf of Mexico is far more complex than previously believed and certainly more complex than many parts of the world ocean. This study, known informally as the "Deep GoM Benthos" study, or "DGoMB", is designed to test a series of working hypotheses based on the best available geochemical, physiographic, and oceanographic information for the Gulf.

Objectives:  The primary objective of this study is to gain a refined view and understanding of benthic communities and habitats on the Gulf of Mexico continental slope. The objective further includes efforts to elucidate several trophic and biogeochemical processes, to erect and quantify major pathways in an ecological model, and to test a number of working hypotheses made possible with modern data.

Methods:  Methods include conventional shipboard sampling and in situ seafloor instrumentation in areas near the influence of known geomorphic, chemical, and topographic complexity, including salt domes, chemosynthetic communities, varying sediment types, authigenic minerals, and in areas subject to geohazards and high currents. Data from this research will be used to predict possible patterns of local and regional biological heterogeneity and levels of complexity better, and to predict how these might relate to environmental patchiness among carefully selected sampling stations. Effective experimental (functional) approaches are being used to supplement the traditional (structural) biological community approaches that have been predominantly used in the past. These include experimental "whole community" respirometry and instrumental estimates of near bottom biomass, and the quantification of trophic relationships. The work for example, focuses on functional feeding guilds, taxonomic groups, and animal size ranges. It complements the NGOMCS information with additional sampling sites, with recognition of new topographic data, and the possible high productivity of upper slope communities. There is some emphasis on energy flow, trophic relationships, and animal functional relationships, with attempts to explain some apparent Gulf anomalies in benthic community structure. This requires a preliminary understanding of the value and possible limitations of existing geological and chemical data sources on the benthic biota and known seafloor features on the slope from 300- to 3,000-m depth.

Products:  Final report.

Importance to MMS:  A better understanding of these conditions and processes unique to deepwater, especially benthic biology is needed to ensure that deepwater development is accomplished in an environmentally safe manner.

Current Status:  The year 1 (2000) "community structure" R/V Gyre cruise was completed very successfully across the northern Gulf, with the sampling of 43 deep stations in the allotted 50 days.

Stations had been selected to represent many habitats, areas and depths, known or hypothesized to influence benthic community structure. At the February 2001 Interim Meeting of investigators and the Scientific Review Board, progress presentations were given and data trends were evaluated to select 12 stations for the Year II, 20-day cruise. The Year II cruise (01-20 June 2001) continued the "community structure" efforts, adding "function" or "process" activities at selected places. New station selections were based on the appearance of biological activity "hot spots", sulfate reduction values, presence of canyons, currents or oxidized surficial crusts, and other criteria. Many stations were in the Central and Eastern Gulf Planning Areas. In October-November 2000, the R/V Atlantis and DSV Alvin were in the Gulf of Mexico, partly in support of DGoMB. Alvin dived on several special deep sites of interest to the program, notably the Sigsbee Escarpment megafurrows, Green Knoll, and the northern Florida Escarpment. A modification was awarded for a joint, Year III Mexican and American cooperative effort which added six new stations in the southern Gulf and samples stations as deep as 3700 m. Two 14-day cruises were conducted in June and August in 2002, completing the field program. All sample and data analyses are complete.

The enormity of the data set was not fully realized until late in the project. The synthesis effort has been recognized by review groups as a very important contribution to Gulf of Mexico deep-sea science. The time period for completion of synthesis and final reporting was extended to insure the best possible product. A cost modification was awarded for an additional $62,390 on 12 October 2005 to fund some additional synthesis and submission of data bases to international database networks. The contract was also modified with a time extension to June 30, 2006. A complete review was completed by the previously selected Science Review Group in January 2006. MMS has received a complete Draft Final report and it has been fully reviewed internally. The contractor has been working on revisions and publications for a special issue of Deep Sea Research II. The remaining draft review process will still take some time and a final report should be available by mid 2008. The two interim reports are referenced below.

Final Report Due:

December 2007 (overdue).  Expected in spring 2008.

Publications:

Deepwater Program: Northern Gulf of Mexico Continental Slope Habitats and Benthic Ecology, Year 1:  Interim Report

Deepwater Program: Northern Gulf of Mexico Continental Slope Habitats and Benthic Ecology:  Interim Report, Year 2

The Role of Small Scale Habitat Heterogeneity on Macrobenthic Diversity in the Deep Northern Gulf of Mexico; presented by A. Ammons, etal. at the annual Aquatic Sciences Meeting of the American Society of Limnology and Oceanography, Albuquerque, New Mexico, 2001.

Deep Sea Seasonality of Benthic Macrofauna in the Northern Gulf of Mexico; presented by Gudeman, et al. at the annual Aquatic Sciences Meeting of the American Society of Limnology and Oceanography, Albuquerque, New Mexico, 2001.

Larsen, K. and Heard, R. Revision of the genus Tanaella (Crustacea: Tanaidacea). Journal of Natural History. Submitted.

Larsen, K., and Heard, R. Depth related changes in biodiversity and possible explanations for recorded distribution patterns of Tanaidacea (Crustacea: Peracarida). Deep-Sea Research. Submitted.

Powell, Shawna M. 2001. Analysis of the fish fauna of the Northern Gulf of Mexico. MES Thesis Report, Environmental Science Program, Memorial University of Newfoundland, vii + 53 pp.

Powell, Shawna M., Richard L. Haedrich and John D. McEachran. 2001. The deep-sea fish fauna of the northern Gulf of Mexico. NAFO SCR 01/143, nr. 4537, 14 pp. [part of a NAFO Symposium on Deep-Sea Fisheries, Varadero, Cuba, September 2001].

Powell, Shawna M., Richard L. Haedrich and John D. McEachran. 2002. The deep-sea fish fauna of the northern Gulf of Mexico. Journal of Northwest Atlantic Fishery Science (in press).

Cunningham, Tarah C. in prep. The deep-sea corals of the Gulf of Mexico, a taxonomic and biogeographic study. B.Sc. Honors thesis, Memorial University. [to be submitted in July 2002].

Rowe, G., A. Lohse, G. Boland, E. Escobar, F. Hubbard and J. Deming. In press. Preliminary trophodynamic carbon budget for the Sigsbee Deep benthos, Northern Gulf of Mexico. Amer. Fish. Soc. Spec. Publ., The Gulf of Mexico: Fish and Fisheries Issues. [This was based on data from our '97 work with UNAM but worked up on MMS time; its the basis of our carbon model.]

Oral Presentations of DGoMB Meiofauna Data

Baguley, Jeffrey, Paul Montagna, Jody Deming, Larry Hyde, and Shelly Carpenter. Trophic interactions between bacteria and meiofauna in the Gulf of Mexico deep-sea: sink or link for carbon secondary production? 31st Annual Benthic Ecology Meeting, Orlando, FL, 2002.

Baguley, Jeff, Larry Hyde, and Paul Montagna. Factors Controlling Meiofauna Abundance and Biomass in the Deep Gulf of Mexico. Eleventh International Meiofauna Conference, Boston, Massachusetts, 2001.

Hyde, Larry and Paul Montagna. Application of Image Analysis to Measure Meiofauna Biomass. Eleventh International Meiofauna Conference, Boston, Massachusetts, 2001.

Affiliated WWW Sites:

The Program Manager, Dr. Gil Rowe, has been invited to attend an oil and gas producers meeting in the UK to discuss deep research for EIS's. For descriptions of two related ongoing MMS studies see:

For more on the MMS Gulf of Mexico Deepwater Program see our Deepwater Environmental Information web site

Revised date:

February 2008

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