FIG. 3.

(A) Methane production from inoculated crushed residual-oil-bearing sandstone core incubations in the absence (closed circles) or presence (open circles) of exogenously added sulfate. Open triangles represent the sulfate concentrations in the sulfate-amended incubations. (B) Methane production from inoculated residual-oil-bearing sandstone core incubations at different salinity levels. Squares, no added NaCl; circles, 1% NaCl; triangles, 2% NaCl. Error bars represent 1 standard deviation of the mean of triplicate incubations.