Scientists Uncover 'Dark Oxygen' Production by Seabed Metals in Groundbreaking Study
Scientists Uncover 'Dark Oxygen' Production by Seabed Metals in Groundbreaking Study
An international team of scientists has discovered that oxygen is being produced by potato-shaped metallic nodules thousands of feet below the surface of the Pacific Ocean.
The findings, published Monday in the journal Nature Geoscience, challenge the scientific consensus on how oxygen is produced and could potentially lead to a radical rethink of the origins of complex life on Earth.
In addition to its implications for ocean science, the research raises new concerns about the risks of deep-sea mining.
Led by Professor Andrew Sweetman of the U.K.’s Scottish Association for Marine Science, the team found that oxygen is being produced in complete darkness approximately 4,000 meters (13,100 feet) below the ocean’s surface.
Previously, it was believed that only living organisms like plants and algae could generate the planet’s oxygen through photosynthesis, a process that requires sunlight.
“For aerobic life to begin on the planet, there had to be oxygen, and our understanding has been that Earth’s oxygen supply began with photosynthetic organisms,” Sweetman said.
“But we now know that oxygen is produced in the deep sea, where there is no light. This discovery prompts us to revisit questions like: where could aerobic life have begun?”
“Dark oxygen” was discovered during ship-based fieldwork in the Pacific Ocean. The team sampled the seabed of the Clarion-Clipperton Zone, an abyssal plain between Hawaii and Mexico, to assess the possible impacts of deep-sea mining.
Researchers analyzed multiple nodules and found many carried a “very high” electric charge, which they said could lead to the splitting of seawater into hydrogen and oxygen through seawater electrolysis.
“Through this discovery, we have generated many unanswered questions, and we need to think carefully about how we mine these nodules, which are effectively batteries in a rock,” Sweetman said.
He added that further research into “dark oxygen” production is necessary.
Deep-Sea Mining
The study was partly funded by Canadian deep-sea mining firm The Metals Co., which aims to begin mining in an area of the Clarion-Clipperton Zone by late 2025.
In a statement to CNBC, The Metals Co. criticized the study’s findings and said it would publish a rebuttal in due course.
The controversial practice of deep-sea mining involves using heavy machinery to remove valuable minerals and metals—such as cobalt, nickel, copper, and manganese—that are found in polymetallic nodules on the ocean floor. These minerals are used in electric vehicle batteries, wind turbines, and solar panels.
Scientists have warned that the full environmental impacts of deep-sea mining are difficult to predict.
Environmental campaign groups argue that the practice cannot be done sustainably and will inevitably lead to ecosystem destruction and species extinction.
“The discovery that a process associated with polymetallic nodules is producing oxygen, in an area targeted by the deep-sea mining industry, supports the urgent need for a moratorium,” said Sofia Tsenikli, deep-sea mining global campaign lead for the Deep Sea Conservation Coalition, a nongovernmental environmental 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 could impact deep-sea life and processes,” Tsenikli said Monday.
