Reduction and Activation of Phosphate on the Primitive Earth

Electrical discharges in water-saturated N₂ containing 1–10% CH₄ were shown earlier toreduce phosphate to phosphite. This mechanism was suggestedas 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 inwhich CO₂ and N₂ are the main components, and studied the effect of introducing smallamounts of H₂ and CO.We show that surprisingly high conversions to phosphite occurin reducing mixtures and thatseveral percent reduction of apatite occurs even in thepresence of as little as 1% each of H₂ and CO. We were also able to confirm a previous report ofpolyphosphate production as a result of heating the mineral apatite in the presence of other minerals.