Deep-ocean floor produces its own oxygen

An international team of researchers has discovered that metallic minerals on the deep-ocean floor produce oxygen -- 13,000 feet below the surface. Discovery challenges long-held assumptions that only photosynthetic organisms generate Earth's oxygen. Minerals at the abyssal seafloor appear to act like geobatteries to produce oxygen in a process that does not require sunlight.

source https://www.sciencedaily.com/releases/2024/07/240722154949.htm