Abstract
Ferruginous (Fe-rich, SO4-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.
| Dokumententyp: | Zeitschriftenartikel |
|---|---|
| Fakultät: | Geowissenschaften > Department für Geo- und Umweltwissenschaften |
| Fakultätsübergreifende Einrichtungen: | GeoBio-Center |
| Themengebiete: | 500 Naturwissenschaften und Mathematik > 550 Geowissenschaften, Geologie
500 Naturwissenschaften und Mathematik > 500 Naturwissenschaften |
| ISSN: | 1462-2912 |
| Sprache: | Englisch |
| Dokumenten ID: | 67826 |
| Datum der Veröffentlichung auf Open Access LMU: | 19. Jul. 2019, 12:23 |
| Letzte Änderungen: | 04. Nov. 2020, 13:50 |
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