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Sulfate reduction and oxic respiration in marine sediments: implications for organic carbon preservation in euxinic environmentsCompilations have been made of sulfate reduction rates and oxic respiration rates over the entire range of marine sedimentation rates, and sedimentary environments, including several euxinic sites. These data show, consistent with the findings of Jorgensen (1982, Nature, 296, 643-645), that sulfate reduction and oxic respiration oxidize equal amounts of organic carbon in nearshore sediments. As sedimentation rates decrease, oxic respiration, becomes progressively more important, and in deep-sea sediments 100-1000 times more organic carbon is oxidized by oxic respiration than by sulfate reduction. By contrast, nearly as much organic carbon is oxidized by sulfate reduction in euxinic sediments as is oxidized by the sum of sulfate reduction and oxic respiration in normal marine sediments of similar deposition rate. This observation appears at odds with the enhanced preservation of organic carbon observed in euxinic sediments. However, only small reductions in (depth-integrated) organic carbon decomposition rates (compared to normal marine) are required to give both high organic carbon concentrations and enhanced carbon preservation in euxinic sediments. Lower rates of organic carbon decomposition (if only by subtle amounts) are explained by the diminished ability of anaerobic bacteria to oxidize the full suite of sedimentary organic compounds.
Document ID
20040089056
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Canfield, D. E.
(NASA Ames Research Center Moffett Field CA United States)
DeVincenzi, D. L.
Date Acquired
August 21, 2013
Publication Date
January 1, 1989
Publication Information
Publication: Deep-sea research. Part A, Oceanographic research papers
Volume: 36
Issue: 1
ISSN: 0198-0149
Subject Category
Exobiology
Funding Number(s)
CONTRACT_GRANT: OCE 8508472
CONTRACT_GRANT: OCE 8219580
Distribution Limits
Public
Copyright
Other
Keywords
NASA Center ARC
NASA Discipline Exobiology

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