Title Biogeochemistry of a low-activity cold seep in the Larsen B area, western Weddell Sea, Antarctica
Author Niemann, H.; Fischer, D.; Graffe, D.; Knittel, K.; Montiel, A.; Heilmayer, O.; Nöthen, K.; Pape, T.; Kasten, S.; Bohrmann, G.; Boetius, A.; Gutt, J.
Author Affil Niemann, H., Max-Planck- Institut für Marine Mikrobiologie, Bremen, Germany. Other: Universität Bremen, Germany; Alfred-Wegener-Institut für Polar- und Meeresforschung, Germany; Universidad de Magallanes, Chile
Source Biogeosciences, 6(11), p.2383-2395, . Publisher: Copernicus GmbH on behalf of the European Union, Katlenburg-Lindau, International. ISSN: 1726- 4170
Publication Date 2009
Notes In English. Published in Biogeosciences Discussions: 18 June 2009, http://www.biogeosciences- discuss.net/6/5741/2009/bgd-6-5741-2009.html; accessed in Feb., 2011; abstract: doi:10.5194/bg-6-2383-2009. 77 refs. Ant. Acc. No: 90936. GeoRef Acc. No: 308340
Index Terms ecosystems; geochemistry; glaciers; hydrocarbons; ocean bottom; sediments; Antarctica--Larsen Ice Shelf; Southern Ocean-- Weddell Sea; aliphatic hydrocarbons; alkanes; anaerobic environment; Antarctic Peninsula; Antarctica; bathymetry; biochemistry; Bivalvia; Calyptogena; cold seeps; Crane and Evans glacier trough; DNA; ethane; Heterodonta; Invertebrata; Larsen Ice Shelf; methane; Mollusca; ocean floors; organic compounds; oxidation; Southern Ocean; sulfates; sulfides; Veneroida; Vesicomyidae; video methods; Weddell Sea; western Weddell Sea
Abstract First videographic indication of an Antarctic cold seep ecosystem was recently obtained from the collapsed Larsen B ice shelf, western Weddell Sea (Domack et al., 2005). Within the framework of the R/V Polarstern expedition ANTXXIII-8, we revisited this area for geochemical, microbiological and further videographical examinations. During two dives with ROV Cherokee (MARUM, Bremen), several bivalve shell agglomerations of the seep-associated, chemosynthetic clam Calyptogena sp. were found in the trough of the Crane and Evans glacier. The absence of living clam specimens indicates that the flux of sulphide and hence the seepage activity is diminished at present. This impression was further substantiated by our geochemical observations. Concentrations of thermogenic methane were moderately elevated with 2 µM in surface sediments of a clam patch, increasing up to 9 µM at a sediment depth of about 1 m in the bottom sections of the sediment cores. This correlated with a moderate decrease in sulphate from about 28 mM at the surface down to 23.4 mM, an increase in sulphide to up to 1.43 mM and elevated rates of the anaerobic oxidation of methane (AOM) of up to 600 pmol cm-3 d-1 at about 1 m below the seafloor. Molecular analyses indicate that methanotrophic archaea related to ANME-3 are the most likely candidates mediating AOM in sediments of the Larsen B seep.
URL http://www.biogeosciences.net/6/2383/2009/bg-6-2383-2009.pdf
Publication Type journal article
Record ID 65004962