An international team of researchers, studying the seabed in the Pacific Ocean’s Clarion-Clipperton Zone, uncovered oxygen-emitting polymetallic nodules on the deep-ocean floor. These metallic minerals, residing in complete darkness, reveal a new mechanism for oxygen production, previously thought to be exclusive to photosynthetic organisms.
Franz Geiger, co-author of the study and leader of the electrochemistry experiments, emphasized the broader implications of this discovery saying, “Especially when considering ocean moons such as Europa.”
This “dark oxygen” discovery was made by Andrew Sweetman of the Scottish Association for Marine Science (SAMS) during ship-based fieldwork in the Pacific Ocean.
“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. But we now know that there is oxygen produced in the deep sea, where there is no light. I think we, therefore, need to revisit questions like: Where could aerobic life have begun,?” Sweetman said.
The oxygen is emitted from polymetallic nodules, natural mineral deposits forming on the ocean surface. These nodules, ranging in size from tiny particles to average-sized potatoes, contain critical metals like cobalt, nickel, copper, lithium, and manganese.
“Several large-scale mining companies now aim to extract these precious elements from the seafloor at depths of 10,000 to 20,000 feet below the surface. We need to rethink how to mine these materials so that we do not deplete the oxygen source for deep-sea life,” Geiger explained.
The study revealed that oxygen production in these nodules occurs through electrochemical reactions, essentially making them natural “geobatteries.” “It appears that we discovered a natural ‘geobattery.’ These geobatteries are the basis for a possible explanation of the ocean’s dark oxygen production.”Geiger added.
To confirm the oxygen production, researchers employed seawater electrolysis, measuring the voltages produced by the nodules from the ocean floor. Their findings suggest that the total mass of polymetallic nodules in the Clarion-Clipperton Zone alone could meet global energy demands for decades.
However, Geiger cautioned against conventional mining practices, noting that bacteria affected by 1980s mining had still not recovered.
The next phase of this research will involve exploring the mechanistic questions posed by these findings, pending further funding.
This study was published in the journal Nature Geoscience.
