Hydrogen gas produced in the subsurface from the hydration of mafic rocks is known to be a
major energy source for chemolithotrophic life in extreme environments such as
hydrothermal vents. The possibility that in situ anaerobic microorganisms present in the
deep subsurface are sustained by low temperature H 2-generating water–rock reactions
taking place around them is being investigated. Whether the growth and activity of H 2-
utilizing microbes directly influences aqueous geochemistry, rates of mineral dissolution …