Data from: Crustal faulting drives biological redox cycling in the deep subsurface

In the deep biosphere, where substrates from the surface are depleted,
microbial communities metabolize using redox pairs from water-rock
reactions. A notable example of this is the production of hydrogen gas
(H2) and oxidants from rock fracturing. However, the potential
interactions between such initial redox pairs and the key iron (Fe)
element are underexplored. Here, we simulated radical-induced water
splitting to investigate how redox gradients form and evolve. In the
presence of Fe, ferrous iron (Fe2+) was marginally oxidized to ferric iron
(Fe3+) by low levels of oxidants, while Fe3+ was significantly reduced by
reactive hydrogen (•H) back to Fe2+. We propose that crustal faulting
could generate various redox pairs and drive Fe redox cycling, thereby
sustaining subsurface life on Earth and other planets.