Food-web structure of seep sediment macrobenthos from the Gulf of Mexico

Amanda W.J. Demopoulos; Daniel Gualtieri; Kaitlin Kovacs

doi:10.1016/j.dsr2.2010.05.011

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USGS · 70003588

Food-web structure of seep sediment macrobenthos from the Gulf of Mexico

Amanda W.J. Demopoulos·Daniel Gualtieri·Kaitlin Kovacs

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Abstract

The slope environment of the Gulf of Mexico (GOM) supports dense communities of seep megafaunal invertebrates that rely on endosymbiotic bacteria for nutrition. Seep sediments also contain smaller macrofaunal invertebrates whose nutritional pathways are not well understood. Using stable-isotope analysis, we investigate the utilization of chemosynthetically fixed and methane-derived organic matter by macrofauna. Biological sampling was conducted in three lower-slope GOM seep environs: Green Canyon (GC852, 1428 m), Atwater Valley (AT340, 2230 m), and Alaminos Canyon (AC601, 2384 m). Infaunal delta 13 C and delta 15 N exhibited a broad range of values; most infauna appeared to be heterotrophic, although several taxa had very light delta 15 N and delta 13 C values, indicating possible reliance on chemoautotrophic symbioses. The lightest delta 13 C and delta 15 N values were observed in nematodes (delta 13 C=-54.6 + or - 0.1 per mil, delta 15 N=-6.1 + or - 0.2 per mil) and one gastropod (delta 13 C=-54.1 per mil, delta 15 N=-1.1 per mil) from Green Canyon. Mixing-model results indicated that sulfur-oxidizing Beggiatoa may be an important food source for seep infauna; the rate of utilization ranged from 60% to 100% at Green Canyon and Atwater Valley. The overall range in isotope values was similar across the three sites, suggesting that biogeochemical processes may be very similar in these geographically distinct areas.

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Source-reported bounding extent: 22° to 32.5° latitude; -98.5° to -85.5° longitude. This indicates report coverage, not an exact sampling location. View area on OpenStreetMap.

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BibTeX RIS

Amanda W.J. Demopoulos, Daniel Gualtieri, Kaitlin Kovacs. 2010. Food-web structure of seep sediment macrobenthos from the Gulf of Mexico. https://doi.org/10.1016/j.dsr2.2010.05.011

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