Predicted catabolic energies (in J per kg of mixed fluid) available for anaerobic oxidation of methane (gray), hydrogenotrophic sulfate reduction (orange), hydrogenotrophic methanogenesis (white), aerobic hydrogen oxidation (blue), aerobic methane oxidation (green), and aerobic sulfide oxidation (red) at 25, 55, and 80°C in mixed abiotic hydrothermal-seawater solutions flowing from Bastille, Dante and Hot Harold.