The surprise finding has many potential implications and could even require rethinking how life first began on Earth, the researchers behind a study said on Monday.
It had been thought that only living things such as plants and algae were capable of producing oxygen via photosynthesis – which requires sunlight.
But four kilometres (2.5 miles) below the surface of the Pacific Ocean, where no sunlight can reach, small mineral deposits called polymetallic nodules have been recorded making so-called dark oxygen for the first time.
The discovery was made in the Clarion-Clipperton Zone (CCZ), an abyssal plain stretching between Hawaii and Mexico, where mining companies have plans to start harvesting the nodules.
The lumpy nodules – often called “batteries in a rock” – are rich in metals such as cobalt, nickel, copper and manganese, which are all used in batteries, smartphones, wind turbines and solar panels.
They then noticed how the nodules were carrying a startling electric charge.
On the surface of the nodules, the team “amazingly found voltages almost as high as are in an AA battery”, Sweetman said. This charge could split seawater into hydrogen and oxygen in a process called seawater electrolysis, the researchers said.
This chemical reaction occurs at about 1.5 volts – approximately the charge of an AA battery.
Nicholas Owens, the SAMS director, said it was “one of the most exciting findings in ocean science in recent times”.
by Agence France-Presse in Paris | Read more:
Image: GSR/Reuters
