An multinational investigation discovered that deep-sea minerals produce oxygen in complete darkness, implying an alternate oxygen source predating photosynthetic life. This discovery has the potential to have an impact on deep-sea mining by underlining the importance of sustainable measures to maintain these oxygen sources. The discovery was first reported in the peer-reviewed journal Nature, and then in other secondary news venues.
Oxygen Production in Depths
An international team of researchers, including a chemist from Northwestern University, discovered that metallic minerals on the deep-ocean floor generate oxygen 13,000 feet below the surface.
This surprise finding calls into question the long-held idea that oxygen is produced solely by photosynthetic organisms such as plants and algae. The study, published in the journal Nature Geoscience, demonstrates that oxygen can be created at the seafloor, where no light can penetrate, enabling aerobic sea life in full darkness.
Polymetallic Nodules are Unveiled
Andrew Sweetman of the Scottish Association for Marine Science (SAMS) discovered “dark oxygen” while conducting fieldwork in the Pacific Ocean. Northwestern’s Franz Geiger led the electrochemistry research that revealed the discovery.
“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 told Reuters. “But we now know there is oxygen produced in the deep sea, where there is no light.”
Polymetallic nodules, or natural mineral deposits on the ocean floor, are essential to this discovery. These nodules contain metals like cobalt, nickel, copper, lithium, and manganese, which are all necessary for battery manufacture.
Implications for Deep Sea Mining
“The polymetallic nodules that produce this oxygen contain metals such as cobalt, nickel, copper, lithium, and manganese,” Geiger said to me. “Several large-scale mining businesses want to collect these elements from the seafloor. We need to reconsider how we mine these resources so that we do not reduce the oxygen supply for deep-sea life.”
Sweetman discovered oxygen production while studying the seafloor of the Clarion-Clipperton Zone, an undersea ridge extending approximately 4,500 miles in the Pacific Ocean. Sweetman’s team initially suspected equipment malfunction, but after a decade of different approaches, they validated their findings.
Hidden ‘Geobatteries’ in Play
In 2023, Sweetman approached Geiger to discuss the oxygen source. Geiger’s prior study demonstrated that rust coupled with saltwater might generate power. The researchers proposed that the deep-ocean polymetallic nodules may generate enough electricity to manufacture oxygen via seawater electrolysis.
Testing this idea, the team discovered that 1.5 volts is sufficient to divide seawater, with nodules producing up to 0.95 volts. “It appears that we discovered a natural ‘geobattery,'” Geiger tweeted.
A New Consideration for Miners.
The researchers believe that the mining sector should examine this discovery before moving forward with deep-sea mining. Geiger observed that mined sites from the 1980s have not recovered, emphasizing the importance of cautious and sustainable mining techniques.
“In unmined regions, marine life flourished,” Geiger remarked. “This puts a major asterisk onto strategies for seafloor mining as ocean-floor faunal diversity in nodule-rich areas is higher than in the most diverse tropical rainforests.”
