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Acetogenesis from CO 2 in an anoxic marine sediment
Author(s) -
Hoehler Tori M.,
Albert Daniel B.,
Alperin Marc J.,
Martens Christopher S.
Publication year - 1999
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1999.44.3.0662
Subject(s) - methanogenesis , anoxic waters , acetogenesis , sulfate , incubation , environmental chemistry , dominance (genetics) , sediment , chemistry , methane , geology , biochemistry , paleontology , organic chemistry , gene
A combination of radiotracer and pore‐water concentration measurements provide evidence for the occurrence of acetogenesis from CO 2 in anoxic marine sediments that are ordinarily dominated by sulfate reduction and methanogenesis. In a month‐long incubation experiment using sediments from Cape Lookout Bight, North Carolina, we measured H 2 and acetate concentrations and monitored the incorporation of 14 CO 2 into 14 CH 4 and 14 C‐acetate. Depletion of pore‐water sulfate resulted in a period of elevated H 2 concentrations that made acetogenic CO 2 reduction thermodynamically favorable. During this period, 14 C‐acetate was produced from 14 CO 2 at rates comparable to those of methanogenesis or sulfate reduction during their respective periods of dominance in the incubation. Maintenance of elevated but constant H 2 concentrations immediately following sulfate depletion likely reflects control by acetogenic bacteria, suggesting they were the dominant consumers of H 2 during this period.