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Biogeochemical cycles of carbon, sulfur, and free oxygen in a microbial matComplete budgets for carbon and oxygen have been constructed for cyanobacterial mats dominated by Microcoleus chthonoplastes from the evaporating ponds of a salt works. We infer from the data the various sinks for O2 as well as the sources of carbon for primary production. Although seasonal variability exists, a major percentage of the O2 produced during the day did not diffuse out of the mat but was used within the mat to oxidize both organic carbon and the sulfide produced by sulfate reduction. At night, most of the O2 that diffused into the mat was used to oxidize sulfide, with O2 respiration of minor importance. During the day, the internal mat processes of sulfate reduction and O2 respiration generated as much or more inorganic carbon (DIC) for primary production as diffusion into the mat. Oxygenic photosynthesis was the most important process of carbon fixation. At night, the DIC lost from the mat was mostly from sulfate reduction. Elemental fluxes across the mat/brine interface indicated that carbon with an oxidation state of greater than zero was taken up by the mat during the day and liberated from the mat at night. Overall, carbon with an average oxidation state of near zero accumulated in the mat. Both carbon fixation and carbon oxidation rates varied with temperature by a similar amount.
Document ID
19940033474
Acquisition Source
Legacy CDMS
Document Type
Reprint (Version printed in journal)
Authors
Canfield, Donald E.
(NASA Ames Research Center Moffett Field, CA, United States)
Des Marais, David J.
(NASA Ames Research Center Moffett Field, CA, United States)
Date Acquired
August 16, 2013
Publication Date
August 1, 1993
Publication Information
Publication: Geochimica et Cosmochimica Acta
Volume: 57
Issue: 16
ISSN: 0016-7037
Subject Category
Life Sciences (General)
Accession Number
94A10129
Distribution Limits
Public
Copyright
Other

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