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dc.contributor.authorShah, Sunita R.  Concept link
dc.contributor.authorJoye, Samantha B.  Concept link
dc.contributor.authorBrandes, Jay A.  Concept link
dc.contributor.authorMcNichol, Ann P.  Concept link
dc.identifier.citationBiogeosciences 10 (2013): 3175-3183en_US
dc.description© The Author(s), 2013. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Biogeosciences 10 (2013): 3175-3183, doi:10.5194/bg-10-3175-2013.en_US
dc.description.abstractOrca Basin, an intraslope basin on the Texas-Louisiana continental slope, hosts a hypersaline, anoxic brine in its lowermost 200 m in which limited microbial activity has been reported. This brine contains a large reservoir of reduced and aged carbon, and appears to be stable at decadal time scales: concentrations and isotopic composition of dissolved inorganic (DIC) and organic carbon (DOC) are similar to measurements made in the 1970s. Both DIC and DOC are more "aged" within the brine pool than in overlying water, and the isotopic contrast between brine carbon and seawater carbon is much greater for DIC than DOC. While the stable carbon isotopic composition of brine DIC points towards a combination of methane and organic carbon remineralization as its source, radiocarbon and box model results point to the brine interface as the major source region for DIC, allowing for only limited oxidation of methane diffusing upwards from sediments. This conclusion is consistent with previous studies that identify the seawater–brine interface as the focus of microbial activity associated with Orca Basin brine. Isotopic similarities between DIC and DOC suggest a different relationship between these two carbon reservoirs than is typically observed in deep ocean basins. Radiocarbon values implicate the seawater–brine interface region as the likely source region for DOC to the brine as well as DIC.en_US
dc.description.sponsorshipThis work was funded by the WHOI Postdoctoral Scholar program, NSF Cooperative Agreement for the Operation of a National Ocean Sciences Accelerator Mass Spectrometry Facility (OCE-0753487), and the US National Science Foundation’s Emerging Frontiers program (award 0801741 to SBJ).en_US
dc.publisherCopernicus Publications on behalf of the European Geosciences Unionen_US
dc.rightsAttribution 3.0 Unported*
dc.titleCarbon isotopic evidence for microbial control of carbon supply to Orca Basin at the seawater–brine interfaceen_US

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Except where otherwise noted, this item's license is described as Attribution 3.0 Unported