Oxygen essential to most complex life on Earth, is primarily produced by plants and photosynthetic organisms on land and underwater. However, a new study published in Nature Geoscience unveils a surprising discovery: oxygen production can occur in complete darkness, deep within the ocean where sunlight never penetrates.
Scientists, aiming to understand oxygen consumption on the seafloor, unexpectedly observed a rise in oxygen levels in certain deep-sea sediments. This finding puzzled researchers, as it defied the typical expectation of oxygen depletion in such environments. The study found that the source of this “dark oxygen” production lies in polymetallic nodules and metalliferous sediments—concentrated deposits of metals on the ocean floor.
These nodules, rich in metals like manganese, cobalt, and copper, can generate electrical currents, enabling electrolysis to split water molecules into hydrogen and oxygen, even in total darkness. This novel process hints that deep-sea mineral deposits could be a hidden reservoir of oxygen, potentially affecting oceanic life and the Earth’s oxygen cycle in ways previously unconsidered.
The implications of this discovery are profound, especially as mining interests expand into deep-sea environments like the Clarion-Clipperton Zone in the Pacific Ocean, where deposits of metals critical for technology, such as lithium and cobalt, are abundant. However, scientists caution that mining could disrupt delicate ecosystems, with sediment plumes posing risks to marine life.
Beyond Earth, the concept of “dark oxygen” opens new possibilities for life in alien environments. This discovery suggests that if similar mineral-rich formations exist on other planets or moons, they might support oxygen production without sunlight, broadening the potential for extraterrestrial life in environments once deemed inhospitable.
This unexpected source of oxygen underscores how much we have yet to uncover about Earth’s origins and the conditions that may sustain life both here and beyond.
Reference: https://www.sciencealert.com/dark-oxygen-discovered-in-the-ocean-but-what-does-it-mean