Calibration of Sulfate Levels in the Archean Ocean

Abstract
The size of the marine sulfate reservoir has grown through Earth's history, reflecting the accumulation of oxygen into the atmosphere. Sulfur isotope fractionation experiments on marine and freshwater sulfate reducers, together with the isotope record, imply that oceanic Archean sulfate concentrations were 2 gas, and severely suppressed sulfate reduction rates allowed for a carbon cycle dominated by methanogenesis.