The finding fills a crucial gap in our understanding of how the huge subterranean biosphere has evolved, and how dismutation contributes to the cycle of compounds moving through the global environment. The mere possibility that oxygen is present in groundwater \u201cchanges our understanding about the past, present and future of subsurface,\u201d said Ruff, who is now an assistant scientist at the Marine Biological Laboratory in Woods Hole, Massachusetts.<\/p>\n

Understanding what lives in the subsurface of our planet is also \u201ccrucial for translating that knowledge elsewhere,\u201d Sherwood Lollar said. The soil of Mars, for instance, contains perchlorate compounds that some Earth microbes can turn into chloride and oxygen. Jupiter\u2019s moon Europa has a deep, frozen ocean; sunlight may not penetrate it, but oxygen could potentially be produced there by microbial dismutation instead of photosynthesis. Scientists have observed plumes of water vapor shooting from the surface of Enceladus, one of the moons of Saturn. The plumes likely originate from a subsurface ocean of liquid water. If we someday find life on other worlds like those, it could be using dismutation pathways to survive.<\/p>\n

Regardless of how important dismutation turns out to be elsewhere in the universe, Lloyd is astonished by how much the new findings defy preconceived notions about life\u2019s needs, and by the scientific cluelessness they reveal about one of the planet\u2019s biggest biospheres. \u201cIt\u2019s as if we have had egg on our face all along,\u201d she said.<\/p>\n

Editor\u2019s note: Ruff has been awarded early career investigator funding by the Simons Foundation, which also supports <\/em>Quanta as an editorially independent science news magazine. Funding decisions do not affect editorial coverage.<\/em><\/p>\n

Correction: July 17, 2023<\/strong><\/em>
An earlier version of this article incorrectly described nitrites as containing three oxygen atoms rather than two.<\/p>\n<\/div>\n

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