How does photosynthesis reverse some of the oxidation effects of Earth’s atmosphere?

Earth’s surface acts as a redox boundary between the planet’s reduced metallic core and an oxidizing atmosphere, which tends to oxidize surface materials. Photosynthesis reverses this oxidative tendency by functioning as a light-energized oxidation-reduction reaction.12

During this process, plants use solar radiation to drive the oxidation of water, which releases oxygen as a by-product. Simultaneously, the energy captured is used to reduce carbon dioxide into complex organic compounds. By converting carbon compounds into lower oxidation states, photosynthesis creates and maintains the chemical potential energy necessary for life, effectively countering the natural tendency of surface materials to be oxidized by the atmosphere. This continuous cycle allows complex biological compounds to persist on Earth’s surface.21