Controls and Consequences of Sulfate Reduction Rates in Recent Marine Sediments

A brief review has been given of the process of bacterial sulfate reduction in respect to other processes in ocean sediments. In particular, rates of sulfate reduction have been discussed in the context of control mechanisms and geochemical consequences. It is concluded that besides temperature and pressure, which are cosmopolitan parameters influencing most biological processes, the rate of sulfate reduction is dependent on (1) total organic carbon preserved in sediment; (2) state of complexing of the organic matter and its availability for biogenic degradation. These two parameters are in turn influenced by (3) the environment of deposition and (4) the rate of sediment accumulation. Correlations are presented that show a direct relationship between rate of sulfate reduction and rate of sediment accumulation. The consequences of different rates of sulfate reduction on pyrite formation and isotope fractionation are discussed.