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Geochemistry, faunal composition and trophic structuring in reducing sediments on the southwest South Georgia margin

Lookup NU author(s): Dr William ReidORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


Despite a number of studies in areas of focused methane seepage, the extent of transitional sediments of more diffuse methane seepage, and their influence upon biological communities is poorly understood. We investigated an area of reducing sediments with elevated levels of methane on the South Georgia margin around 250m depth and report data from a series of geochemical and biological analyses. Here, the geochemical signatures were consistent with weak methane seepage and the role of sub-surface methane consumption was clearly very important, preventing gas emissions into bottom waters. As a result, the contribution of methane-derived carbon to the microbial and metazoan food webs was very limited, although sulfur isotopic signatures indicated a wider range of dietary contributions than was apparent from carbon isotope ratios.Macrofaunal assemblages had high dominance and were indicative of reducing sediments, with many taxa common to other similar environments and no seep-endemic fauna, indicating transitional assemblages. Also similar to other cold seep areas, there were samples of authigenic carbonate but rather than occurring as pavements or sedimentary concretions, these carbonates were restricted to patches on the shells of Axinulus antarcticus (Bivalvia, Thyasiridae), which is suggestive of microbe–metazoan interactions.

Publication metadata

Author(s): Bell JB, Aquilina A, Woulds C, Glover AG, Little CTS, Reid WDK, Hepburn LE, Newton J, Mills RA

Publication type: Article

Publication status: Published

Journal: Royal Society Open Science

Year: 2016

Volume: 3

Print publication date: 28/09/2016

Online publication date: 28/09/2016

Acceptance date: 25/08/2016

Date deposited: 03/10/2016

ISSN (electronic): 2054-5703

Publisher: The Royal Society Publishing


DOI: 10.1098/rsos.160284


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Funder referenceFunder name
NE/DOI249X/INERC ChEsSo consortium (Chemosynthetically driven Ecosystems South of the Polar Front, NERC grant)
EK246-01/15NERC Life Sciences Mass Spectrometry Facility