Reduction and activation of phosphate on the primitive earth

Abstract

Electrical discharges in water-saturated N2 containing 1-10% CH4 were shown earlier to reduce phosphate to phosphite. This mechanism was suggested as a possible source of water-soluble phosphorus-containing compounds in volcanic environments on the prebiotic Earth. We have now extended our investigations to gas mixtures in which CO2 and N2 are the main components, and studied the effect of introducing small amounts of H2 and CO. We show that surprisingly high conversions to phosphite occur in reducing mixtures and that several percent reduction of apatite occurs even in the presence of as little as 1% each of H2 and CO. We were also able to confirm a previous report of polyphosphate production as a result of heating the mineral apatite in the presence of other minerals.