Pyrite-Induced Hydrogen Peroxide Formation as a Driving Force in the Evolution of Photosynthetic Organisms on an Early Earth

The remarkable discovery of pyrite-induced hydrogen peroxide (H₂O₂) provides a key step in the evolution of oxygenic photosynthesis. Here we show that H₂O₂ can be generated rapidly via a reaction between pyrite and H₂O in the absence of dissolved oxygen. The reaction proceeds in the dark, and H₂O₂ levels increase upon illumination with visible light. Since pyrite was stable in most photic environments prior to the rise of O₂ levels, this finding represents an important mechanism for the formation of H₂O₂ on early Earth.