"Something is pumping out large amounts of oxygen at the bottom of the Pacific Ocean, at depths where a total lack of sunlight makes photosynthesis impossible."
"Andrew Sweetman, a sea-floor ecologist at the Scottish Association for Marine Science in Oban, UK, and his collaborators first noticed something amiss during field work in 2013. The researchers were studying sea-floor ecosystems in the Clarion-Clipperton Zone, an area between Hawaii and Mexico that is larger than India and a potential target for the mining of metal-rich nodules. During such expeditions, the team releases a module that sinks to the sea floor to perform automated experiments. Once there, the module drives cylindrical chambers down to close off small sections of the sea floor -- together with some seawater -- and create 'an enclosed microcosm of the seafloor'." "The lander then measures how the concentration of oxygen in the confined seawater changes over periods of up to several days."
"Without any photosynthetic organisms releasing oxygen into the water, and with any other organisms consuming the gas, oxygen concentrations inside the chambers should slowly fall. Sweetman has seen that happen in studies he has conducted in areas of the Southern, Arctic and Indian oceans, and in the Atlantic. Around the world, sea-floor ecosystems owe their existence to oxygen carried by currents from the surface, and would quickly die if cut off."
"But in the Clarion-Clipperton Zone, the instruments showed that the sequestered water became richer, not poorer, in oxygen. At first, Sweetman attributed the readings to a sensor malfunction. But the phenomenon kept occurring during subsequent trips in 2021 and 2022, and was confirmed by measurements with an alternative technique."
"We have another source of oxygen on the planet, other than photosynthesis."
Mystery oxygen source discovered on the sea floor -- bewildering scientists
