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Geochemistry, faunal composition and trophic structure in reducing sediments on the southwest South Georgia margin
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 Geor...
Autores principales: | , , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
The Royal Society
2016
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5043311/ https://www.ncbi.nlm.nih.gov/pubmed/27703692 http://dx.doi.org/10.1098/rsos.160284 |
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author | Bell, James B. Aquilina, Alfred Woulds, Clare Glover, Adrian G. Little, Crispin T. S. Reid, William D. K. Hepburn, Laura E. Newton, Jason Mills, Rachel A. |
author_facet | Bell, James B. Aquilina, Alfred Woulds, Clare Glover, Adrian G. Little, Crispin T. S. Reid, William D. K. Hepburn, Laura E. Newton, Jason Mills, Rachel A. |
author_sort | Bell, James B. |
collection | PubMed |
description | 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 250 m 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. |
format | Online Article Text |
id | pubmed-5043311 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2016 |
publisher | The Royal Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-50433112016-10-04 Geochemistry, faunal composition and trophic structure in reducing sediments on the southwest South Georgia margin Bell, James B. Aquilina, Alfred Woulds, Clare Glover, Adrian G. Little, Crispin T. S. Reid, William D. K. Hepburn, Laura E. Newton, Jason Mills, Rachel A. R Soc Open Sci Earth Science 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 250 m 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. The Royal Society 2016-09-28 /pmc/articles/PMC5043311/ /pubmed/27703692 http://dx.doi.org/10.1098/rsos.160284 Text en © 2016 The Authors. http://creativecommons.org/licenses/by/4.0/ Published by the Royal Society under the terms of the Creative Commons Attribution License http://creativecommons.org/licenses/by/4.0/, which permits unrestricted use, provided the original author and source are credited. |
spellingShingle | Earth Science Bell, James B. Aquilina, Alfred Woulds, Clare Glover, Adrian G. Little, Crispin T. S. Reid, William D. K. Hepburn, Laura E. Newton, Jason Mills, Rachel A. Geochemistry, faunal composition and trophic structure in reducing sediments on the southwest South Georgia margin |
title | Geochemistry, faunal composition and trophic structure in reducing sediments on the southwest South Georgia margin |
title_full | Geochemistry, faunal composition and trophic structure in reducing sediments on the southwest South Georgia margin |
title_fullStr | Geochemistry, faunal composition and trophic structure in reducing sediments on the southwest South Georgia margin |
title_full_unstemmed | Geochemistry, faunal composition and trophic structure in reducing sediments on the southwest South Georgia margin |
title_short | Geochemistry, faunal composition and trophic structure in reducing sediments on the southwest South Georgia margin |
title_sort | geochemistry, faunal composition and trophic structure in reducing sediments on the southwest south georgia margin |
topic | Earth Science |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5043311/ https://www.ncbi.nlm.nih.gov/pubmed/27703692 http://dx.doi.org/10.1098/rsos.160284 |
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