FIG 2.

Sulfate reduction (yellow) and methanogenesis (orange) in CSBA-S medium with 3 mM propionate (A, B, and C; microcosm E_S2P3_15) or butyrate (D, E, and F; microcosm E_S2B3_16) and inoculated with 2PW enrichment. (D, E, and F) Color overlap indicates that the two processes occurred simultaneously. The concentrations of sulfate, sulfide, propionate, butyrate, and acetate in the aqueous phase and of methane in the headspace are shown as a function of time. The data represent averages of results from duplicate incubations, with standard deviations shown when these exceed the size of the symbols. The numbered arrows indicate sampling for DNA isolation.