last highlighted date: 2024-11-05
Highlights
- 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 metallic “nodules” which split seawater - H2O - into hydrogen and oxygen.
- Several mining companies have plans to collect these nodules, which marine scientists fear could disrupt the newly discovered process - and damage any marine life that depends on the oxygen they make.
- “I first saw this in 2013 - an enormous amount of oxygen being produced at the seafloor in complete darkness,” explains lead researcher Prof Andrew Sweetman from the Scottish Association for Marine Science. “I just ignored it, because I’d been taught - you only get oxygen through photosynthesis.
- And because these nodules contain metals like lithium, cobalt and copper - all of which are needed to make batteries - many mining companies are developing technology to collect them and bring them to the surface.
- The scientists worked out that the metal nodules are able to make oxygen precisely because they act like batteries.
- This means, they say, that the nodules sitting on the seabed could generate electric currents large enough to split, or electrolyse, molecules of seawater.
- The US National Oceanic and Atmospheric Administration (NOAA) has warned that this seabed mining could “result in the destruction of life and the seabed habitat in the mined areas”.
- More than 800 marine scientists from 44 countries have signed a petition highlighting the environmental risks and calling for a pause on mining activity.