Carbon Metabolisms and Environmental Adaptation in Sulfate Reducers
Sulfate-reducing prokaryotes (SRPs) play a central role in sulfur- and carbon-cycles in marine sediments. SRPs couple the oxidation of electron donors to the reduction of sulfate (SO42-) to sulfide (S2-). The global abundance of sulfate (28 mM in seawater) accounts for a more than 50% contribution of SRPs to the organic carbon remineralisation in biologically active shelf sediments, as encountered in the North Sea. This high remineralisation rate is based on the capacity for complete oxidation of organic substrates to CO2 as well as on high versatility with respect to the utilizable organic substrates. Both metabolic properties are characteristic for members of the Desulfobacteriaceae, e.g. lang chain fatty acid utilization by Desulfobacterium autotrophicum and anaerobic aromatic compound degradation by Desulfobacula toluolica. The rise of marine genomics now allows for the first time comprehensive molecular studies of this ecophysiologically important group of completely oxidizing sulfate-reducing bacteria. A detailed understanding of major metabolic pathways and their environmentally controlled performance will advance our understanding of the biogeochemical cycles driven by SRPs.
G2L Göttingen (G. Gottschalk), MPI Bremen (F. Widdel, R. Amann), MPI Berlin (R. Reinhard), University of Oklahoma (B. Wawrik), University Missoury-Columbia (J. Wall)