In the Clarion-Clipperton Zone, researchers found that polymetallic nodules-metal-rich rocks spread across the seafloor-may be creating oxygen in complete darkness. Acting like tiny natural batteries, these nodules split seawater into hydrogen and oxygen through electrochemical reactions, without sunlight or microbes.
This process, now called "dark oxygen," challenges the long-standing idea that oxygen can only be produced through
photosynthesis. It could offer clues about how life began on Earth-and how it might exist on other planets.
