Mafic-ultramafic igneous rocks as a source of reactive phosphorus for the origin of life

Phosphite and pyrophosphate-reduced and polymerized forms of phosphorus-may have played a central role in prebiotic chemistry owing to their higher reactivity and solubility, yet their geological sources remain uncertain. Here we show that mafic-ultramafic rocks on the early Earth could have provided a sustained source of reactive phosphorus through seafloor weathering. Rock analyses from 15 localities reveal phosphite comprising up to 7%, 24%, 17%, and 0.6% of total phosphorus in olivine separates, peridotite, komatiite, and basalt, respectively, while pyrophosphate accounts for up to 5% and 0.4% in komatiite and basalt. Box-model calculations indicate phosphite concentrations reaching up to 1 µM in the deep ocean and up to 67 µM in lakes under low-UV conditions. We suggest that reactive phosphorus released from mafic-ultramafic rocks could have fuelled prebiotic phosphorylation and supplied phosphate to emerging life on Earth, a process that may also enhance the habitability of other planetary bodies.