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Gulf of Mexico hydrocarbon seep communities—I. Regional distribution of hydrocarbon seepage and associated fauna

1988; Pergamon Press; Volume: 35; Issue: 9 Linguagem: Inglês

10.1016/0198-0149(88)90107-0

1878-2477

Mahlon C. Kennicutt, James M. Brooks, Robert R. Bidigare, G.J. Denoux,

Geology and Paleoclimatology Research

A series of otter trawls demonstrate that communities based on chemosynthesis are broadly distributed across the northwestern Gulf of Mexico continental slope in hydrocarbon seep areas. Thirty-nine trawls were taken at 33 locations reported to exhibit transparent or chaotic seismic “wipe-out” zones. The sites, in water depths from 180 to 900 m, span an area from offshore the Mississippi River delta to the upper Texas continental slope. Endosymbiont-containing organisms or their remains (either tube worms, mussels and/or clams) were recovered at 21 sites on the northern Gulf of Mexico slope. Tube worms, clams and mussels known to be associated with symbionts were retreived at 18, 12 and 5 sites, respectively. Carbon isotope analysis of selected animal tissues confirmed the chemosynthetic association. Animals containing isotopically light chemosynthetic carbon were collected at 21 sites. Piston cores at each site were used to determine the presence of mature hydrocarbons. Nine of 30 piston cores were visibly oil-stained. Trawl collections at locations where visibly oil-stained cores were recovered contained at least one species of chemosynthetic-associated organism and generally represented the most abundant catches of endosymbiont-containing animals. The chemical environment (oil and gas seepage) necessary to support chemosynthetic-based ecosystems is widespread on the northern Gulf of Mexico continental slope.