ACCESS NUMBER: 30660-19904 

STUDY TITLE: Development of an Ecological Overview Appropriate for Management 

of Resource Development in Continental Slope Habitats 

REPORT TITLE: Management Applicability of Contemporary Deep-Sea Ecology and 

Reevaluation of Gulf of Mexico Studies 

CONTRACT NUMBERS: 14-35-0001-30660-19904 

SPONSORING OCS REGION: Gulf of Mexico 

APPLICABLE PLANNING AREA: Central Gulf 

FISCAL YEARS OF PROJECT FUNDING: 1993, 1994 

COMPLETION DATE OF REPORT: 2001 

COSTS: FY 93 $43,482; FY 94 $34,558; CUMULATIVE PROJECT COSTS: $79,014 

PROJECT MANAGER: Robert S. Carney 

AFFILIATION: Coastal Ecology Institute, Louisiana State University 

ADDRESS: Coastal Ecology Institute, Louisiana State University, Baton Rouge, La. 

70803 

PRINCIPAL INVESTIGATOR: Robert S. Carney 

KEY WORDS: Deep-sea Ecology, Deep-sea Conservation Coastal, Deep Gulf of 

Mexico, Deep-sea Exploitation. 

BACKGROUND: The study of deep-sea biology began in the late 1800’s, with an 

ecological perspective being adopted after the 1900’s. Unlike terrestrial and neritic 

ecology, an applied or bio-conservation approach to deep-sea ecology has yet to be 

developed. As a result, when resource managers and regulators turn to the body of 

deep-sea knowledge in an effort to develop scientifically sound strategies, they 

encounter many facts and theories but little indication as to the mission relevance of 

any. Which of all the fascinating scientific ideas about deep-sea distributions, 

adaptation, trophic relationships, reproduction, competition, community structure, biodiversity, etc. are best able to predict, monitor for, and mediate environmental impacts? 

OBJECTIVES: The overall goal of the project is to provide the Minerals Management 

Service with a sense of the status and mission relevance of a cross-section of deep-sea 

ecology topics. Focusing primarily on the Gulf of Mexico, there are three objectives: (1) 

to provide an annotated review of relevance of general deep-sea ecology; (2) review 

and reevaluate in a more contemporary context MMS-supported surveys of the 1980’s, 
ACCESS NUMBER: 30660-19904 

and (3) review and update Gulf of Mexico chemosynthetic community studies from a 

similar perspective. 

DESCRIPTION: The study consisted of three parts. Part one is a status review of 

deep-sea ecology concepts and capabilities reflected by the open literature up to 1995 

with selected additions until 2001. Included in this review are brief consideration of 

previous deep-sea regulatory efforts dealing with manganese nodule mining, radioactive 

waste, and deep-sea disposal. Part two is a review and reexamination of data from the 

Northern Gulf of Mexico Continental Slope (NGMCS) program and the Atlantic 

Continental Slope and Rise (ACSR) program. Both studies were conducted prior to the 

refinement of concerns brought about by actual initiation of deep-water development 

and prior to recent deep-sea ecological syntheses. Part two is a review and extension 

of work on the Gulf of Mexico chemosynthetic communities. A model of 

geological/geochemically mediated substrate suitability is proposed. 

SIGNIFICANT CONCLUSIONS: Over the last ten years, many generalities about 

deep-sea adaptation have been questioned and some disproved, thus blurring 

previously identified distinctions between shallow and deep systems. The most notable 

aspects of deep-sea ecology with greatest relevance to environmental impact are: 

(1) From the legally defined upper limit of 200m to the typical maximum depth of the 

US EEZ at about 3600m there are dramatic changes in habitat and species 

composition. Management strategies may require depth stratification. 

(2) Embedded within the vast soft-bottom habitat are faunally distinct, smaller-scale 

“special habitats” such as chemosynthetic communities, cold-water corals, sponge 

banks. Special management strategies may be required to protect each such habitat. 

(3) Most deep fauna is dependent upon the detrital rain of labile carbon, and the 

paucity of that resource may play a far greater role in community structure than in 

shallow water. Activities that alter the influx and short-term redistribution of detritus 

should be examined as potential causes of deleterious impact. 

(4) The most notable deep-sea phenomenon that gives evidence of a deep ecology 

unlike that of shallow water is the very high biological diversity in a seemingly 

homogenous habitat. The explanations that have been put forward for such high 

diversity do not address the issue of impacting activities. Efficient management 

requires that the causative processes be confidently determined. 

STUDY RESULTS: Activity for part one consisted of a literature search and reading of 

all relevant major works on deep-sea ecology from 1960-1996. Part two activities 

consisted of a review of all reports and publications associated with the NGMCS and 

ACSR programs. Faunal datasets for NGMCS were recreated in National 

Oceanographic Data Center format from annual reports. Faunal datasets for ACSR 

were obtained from Battelle Inc. On reanalysis some of the original NGMCS 

conclusions about east-west and depth faunal distributions were found dubious due to 
ACCESS NUMBER: 30660-19904 

the low power of the designs used. Use of dissimilar gear prevented confident 

comparison of results, but some indication of higher species diversity in the Gulf of 

Mexico was found. Activitie for the third part consisted of literature review and 

examination of archived video footage take at seep sites. These allowed consideration 

of a model whereby time-variant seepage rates produce a transition between fluid-prone 

and mineral-prone seafloor habitats. The latter support metazoan chemosynthetic 

communities. 

STUDY PRODUCTS: Carney, R.S. 2001. Management applicability of contemporary 

deep-sea ecology and reevaluation of Gulf of Mexico Studies. Final report. OCS Study 

MMS-2001- 095. U.S. Department of the Interior, Minerals Management Service, Gulf 

of Mexico OCS Region, New Orleans, La. 190 pp.