- An international team of scientists has found that oxygen is produced in total darkness approximately 4,000 meters (13,100 feet) below the ocean’s surface.
- Previously, it was thought that only living organisms such as plants and algae could use energy to create oxygen on the planet through a process called photosynthesis, which requires sunlight.
- The researchers took samples from the sea floor of the Clarion-Clapperton Zone, an abyssal plain between Hawaii and Mexico, to assess the possible impacts of deep-sea mining.
A team of international scientists has found that oxygen is produced in complete darkness approximately 4,000 meters below the surface of the ocean.
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An international team of scientists has discovered that oxygen is produced by potato-shaped metal nodules thousands of feet below the surface of the Pacific Ocean.
The findings, which were published Monday in the journal Nature Geoscience, contradict the scientific consensus about how oxygen is produced — and could even force a radical rethinking of the origins of complex life on Earth.
Along with implications for ocean science, the study raises new concerns about the risks of deep-sea mining.
A team of scientists led by Professor Andrew Sweetman of the UK’s Scottish Marine Science Association found that oxygen is produced in complete darkness approximately 4,000 meters (13,100 feet) below the ocean’s surface.
Previously, it was thought that only living organisms such as plants and algae could use energy to create oxygen on the planet through a process called photosynthesis, which requires sunlight.
“For aerobic life to begin on the planet, there had to be oxygen, and our understanding is that the oxygen supply to Earth was started by photosynthetic organisms,” Sweetman said.
“But now we know there is oxygen produced in the deep sea where there is no light. I think we therefore need to re-examine questions such as: where might aerobic life have begun?’
Critical minerals such as cobalt, nickel, copper and manganese can be found in potato-sized nodules at the bottom of the seabed.
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The “dark oxygen” was discovered while researchers were conducting fieldwork on a ship in the Pacific Ocean. The team sampled the sea floor of the Clarion-Clapperton Zone, an abyssal plain between Hawaii and Mexico, to assess the possible impacts of deep-sea mining.
The researchers analyzed multiple nodules and found that many of them carry a “very high” electrical charge, which they say could cause seawater to split into hydrogen and oxygen through a process called seawater electrolysis.
“With this discovery, we’ve created a lot of unanswered questions, and I think we have a lot to think about in terms of how we mine these nodules, which are essentially batteries in a rock,” Sweetman said.
He added that further research would be needed to produce “dark oxygen”.
The exploration is partially funded by Canadian deepwater mining firm The Metals Company, which aims to mine in an area of the Clarion-Clapperton zone by the end of 2025.
The controversial practice of deep-sea mining involves the use of heavy machinery to remove valuable minerals and metals – such as cobalt, nickel, copper and manganese – that can be found in polymetallic nodules on the ocean floor. The end uses of these minerals are wide-ranging and include batteries for electric vehicles, wind turbines and solar panels.
Scientists have warned that the full environmental impact of deep-sea mining is difficult to predict.
In this footage provided by Greenpeace, Greenpeace activists protest outside the Hilton, Canary Wharf on the morning of the opening of the annual Deep Sea Mining Summit on April 17, 2024 in London, England.
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Environmental campaign groups, meanwhile, say the practice cannot be carried out sustainably and will inevitably lead to ecosystem destruction and species extinction.
“The discovery that a process involving polymetallic nodules produces oxygen in an area targeted by the deep-sea mining industry provides further support for the urgent need for a moratorium,” said Sofia Cenikli, head of the global deep-sea mining campaign Deep Sea Conservation Coalition, a non-governmental ecological group.
“This research highlights how much we still have to discover and learn about the deep sea and raises more questions about how deep-sea mining may affect deep-sea life and processes,” Cenikli said Monday.
