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

As part of its Environmental Studies Program, the Minerals Management Service (MMS) of the Department of the Interior has awarded a contract to Texas A&M University (TAMU) for $4,600,000 to investigate the ecology of organisms living on the deep-sea floor of the continental slope of the northern Gulf of Mexico.  The MMS is responsible for collecting environmental information that will help in the preparation of its Environmental Impact Statements and Assessments related to MMS’s mandated regulation of offshore oil exploration and production.  This research is important, given the industry's increasing interest in deep petroleum prospects, especially those that occur deeper on the slope.

This program is believed to be one of the largest single studies, ever, of the deep-sea "benthos" (seafloor organisms).  The Program Manager of this four-year effort is Dr. Gilbert T. Rowe of the Oceanography Department and the Deputy Program Manager is Dr. Mahlon C. Kennicutt II, the Director of the Geochemical and Environmental Research Group (GERG).  A major part of the investigations will be conducted by an interdisciplinary team in TAMU with collaborating marine biologists from the University of Southern Mississippi, Los Angeles County Museum, Memorial University of Newfoundland, the University of Washington, the Swedish National Museum, and the National University of Mexico in Mexico City.

The purpose of the Deep Gulf of Mexico Benthos Study (DGoMB) is to gather detailed information on the composition and function of seafloor animal communities from water depths of 300 m out to over 3,000 m (approximately 1,000 to 10,000 feet).  The main field sampling effort is being carried out on the university's 182-ft. oceanographic research vessel, the R/V Gyre, berthed at the TAMU campus in Galveston.  The program will provide a better understanding of

• the present composition and structure of deep biological communities in the Gulf,
• the distribution and abundance patterns of important deep-sea biota,
• the biological and physical processes that control the environmental settings and
• the effects that these processes have on the character of benthic communities,
• the relationship between these communities and local conditions and forcing factors,
• the "health" and organic functioning of deep-sea communities, and
• the Gulf of Mexico slope as it compares and contrasts with similar oceanic basins.

The study is divided into four important phases:

The first completed phase entailed a thorough review of background information already available from previous studies of the Gulf of Mexico, much of which was supported by MMS in the 1980's and 1990's.

The second phase, a major field sampling in Year I, was conducted during a 50-day cruise in 2000.  It followed a detailed R/V Gyre sampling plan (see the attached map) to describe "community structure," defined as species diversity and composition, size distributions, biomass levels, and zonation relative to depth and other environmental factors (temperature, oxygen, sediment type, etc.).  The sampling plan was designed to test a number of working hypotheses developed with a new detailed understanding of the geology and geochemistry of the deep Gulf.  But not all of the needed information could be retrieved from the sea surface with conventional samplers.  Therefore, an integral, manned-submersible component of the DGoMB Study was conducted (October 2000) by Drs. Ian MacDonald (GERG) and William Bryant (TAMU, Oceanography), who are investigating the fauna and geology of the lower Sigsbee and Florida Escarpments.  These study elements required the unique deep sampling and observational capabilities of the deep submergence vehicle (DSV) Alvin, a venerable research submersible from the Woods Hole Oceanographic Institution in Massachusetts, and its new, high-technology, surface support ship, the R/V Atlantis.  This cruise, organized and largely supported by NOAA's National Underwater Research Program (NURP), provided deep dives for the DGoMB Study and other investigations of chemosynthetic communities, gas hydrates, and bottom ecology.  The MMS provided supplemental support for data analyses and dive-time for MMS objectives.

The third phase, the study of "ecosystem function" (Years II and III in 2001-2002), will be designed on the basis of conceptual ecosystem models developed from what can be inferred from the Year I, community-structure work.  This phase will investigate the rates of processes for which the communities of deep-ocean organisms are responsible, such as the cycling of organic matter, regeneration of nutrients, transfers of energy and contaminants up the food chain, etc.  Site-specific, near-bottom food chain models will be used to design comprehensive seafloor experiments and sampling frequencies that will provide knowledge of rates of processes in natural ecosystems from Texas to Florida.  The models will also be used to make hypothetical predictions of the ways in which offshore activities could affect deep ocean life, both positively and negatively.

The final and fourth phase will be devoted to synthesis and integration of the statistical models generated by the studies of community structure and the time-dependent numerical simulations of material cycling that result from studies of community function.  Specimens will be distributed to recognized taxonomic specialists for identification, and the collected specimens will be retained by the U.S National Museum of the Smithsonian Institution.

MMS is the Federal agency that manages the Nation's natural gas, oil and other mineral resources on the OCS, and collects, accounts for and disburses about $4 billion yearly in revenues from offshore Federal mineral leases and from onshore mineral leases on Federal and Indian lands.

Figure 1.  Cruise track for the first survey.

-MMS-GOM-
MMS's Website Address:  http://www.mms.gov