Figure 4: CO2 partial pressure effect on change in Gibbs free energy for acetate oxidation and methanogeneses.
From: Carbon dioxide concentration dictates alternative methanogenic pathways in oil reservoirs
Effect of CO2 partial pressure on the change in Gibbs free energy for acetate oxidation, hydrogenotrophic methanogenesis and acetoclastic methanogenesis. (a) The setup conditions are at 116 days of incubation in the control microcosm: acetate at 0.3 mM, methane at 0.51 atm, hydrogen at 1.5 × 10−4 atm, pH=8.1, at 55 °C and 50 atm. (b) The setup conditions are at 77 days of incubation in the CO2-injected microcosm: acetate at 0.4 mM, methane at 0.66 atm, hydrogen at 1.2 × 10−4 atm, pH=7.3, at 55 °C and 50 atm. Dashed lines indicate actual CO2 partial pressures (0.04 and 2.0 atm) in the control and CO2-injected microcosms, respectively.
