One of the earliest things we learn in a school science class is that Earth’s life-sustaining oxygen is produced by plants during photosynthesis, but...
The recent discovery of what researchers call “dark oxygen” may upend conventional notions of how the critical element can be created - and what that might mean for the origins of life, says Popular Science.
Scientists have discovered “dark oxygen” being produced in the deep ocean, apparently by lumps of metal on the seafloor. About half the oxygen we breathe comes from the ocean. But, before this discovery, it was understood that it was made by marine plants photosynthesising - something that requires sunlight.
Here, at depths of 5km, where no sunlight can penetrate, the oxygen appears to be produced by naturally occurring - in a process that takes millions of years - metallic “nodules” which split seawater - H2O - into hydrogen and oxygen.
Working in an area of the deep sea between Hawaii and Mexico, Prof Andrew Sweetman from the Scottish Association for Marine Science saw "an enormous amount of oxygen being produced at the seafloor in complete darkness.” Initially, he "just ignored it, because I’d been taught - you only get oxygen through photosynthesis. Eventually, I realised that for years I’d been ignoring this potentially huge discovery,” he told BBC News.
Prof Sweetman says the dark oxygen they make could also support life on the seafloor. And his discovery, published in the journal Nature Geoscience, raises new concerns about the risks of proposed deep-sea mining ventures.
More than 800 marine scientists from 44 countries have signed a petition, external highlighting the environmental risks and calling for a pause on mining activity. Prof Murray Roberts, a marine biologist from the University of Edinburgh is one of the scientists who signed the seabed mining petition. “There’s already overwhelming evidence that strip mining deep-sea nodule fields will destroy ecosystems we barely understand,” he told BBC News.