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Metabolic potential of microbial communities from ferruginous sediments
Author(s) -
Vuillemin Aurèle,
Horn Fabian,
Friese André,
Winkel Matthias,
Alawi Mashal,
Wagner Dirk,
Henny Cynthia,
Orsi William D.,
Crowe Sean A.,
Kallmeyer Jens
Publication year - 2018
Publication title -
environmental microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.954
H-Index - 188
eISSN - 1462-2920
pISSN - 1462-2912
DOI - 10.1111/1462-2920.14343
Subject(s) - methanogenesis , biogeochemical cycle , sulfate , anoxic waters , acetogenesis , biology , microbial population biology , environmental chemistry , archean , microbial metabolism , anaerobic oxidation of methane , sediment , extreme environment , anaerobic respiration , ecology , methane , chemistry , anaerobic exercise , bacteria , paleontology , genetics , physiology , organic chemistry
Summary Ferruginous (Fe‐rich, SO 4 ‐poor) conditions are generally restricted to freshwater sediments on Earth today, but were likely widespread during the Archean and Proterozoic Eons. Lake Towuti, Indonesia, is a large ferruginous lake that likely hosts geochemical processes analogous to those that operated in the ferruginous Archean ocean. The metabolic potential of microbial communities and related biogeochemical cycling under such conditions remain largely unknown. We combined geochemical measurements (pore water chemistry, sulfate reduction rates) with metagenomics to link metabolic potential with geochemical processes in the upper 50 cm of sediment. Microbial diversity and quantities of genes for dissimilatory sulfate reduction ( dsrAB ) and methanogenesis ( mcrA ) decrease with increasing depth, as do rates of potential sulfate reduction. The presence of taxa affiliated with known iron‐ and sulfate‐reducers implies potential use of ferric iron and sulfate as electron acceptors. Pore‐water concentrations of acetate imply active production through fermentation. Fermentation likely provides substrates for respiration with iron and sulfate as electron donors and for methanogens that were detected throughout the core. The presence of ANME‐1 16S and mcrA genes suggests potential for anaerobic methane oxidation. Overall our data suggest that microbial community metabolism in anoxic ferruginous sediments support coupled Fe, S and C biogeochemical cycling.