The production of “dark oxygen” on the deep ocean floor has been discovered by scientists, upending long-held beliefs about how oxygen is produced on Earth. Researchers discovered that polymetallic nodules on the bottom function as organic “geobatteries,” generating oxygen through electrolysis at depths where sunlight does not reach. These findings have the potential to fundamentally alter our understanding of deep-sea ecosystems and the emergence of life.

Finding Dark Oxygen

While investigating the seafloor of the Pacific Ocean’s Clarion-Clipperton Zone in 2013, Andrew Sweetman and his colleagues from the Scottish Association for Marine Science uncovered an unexpected finding. Their sensors picked up the production of oxygen at 13,100 feet (4,000 meters), a depth where light does not reach. Recurring observations over a ten-year period verified the existence of this “dark oxygen” production, which challenged the conventional wisdom that oxygen formation necessitates photosynthesis. Initially, the findings were written off as malfunctioning equipment. The discovery, which was reported in Nature Geoscience, showed that polymetallic nodules on the ocean floor function as organic geobatteries, generating oxygen in total darkness via the electrolysis of saltwater.

Mechanism Of Polymetallic Nodules

These seafloor formations, which can be as small as particles or as large as lumps the size of potatoes, are rich in cobalt, nickel, copper, manganese, and lithium. Clusters may produce voltages higher than the 1.5 volts needed for water electrolysis, although single nodules may produce voltages as high as 0.95 volts. In order to break water molecules into hydrogen and oxygen, the nodules function as organic geobatteries in the saltwater, producing an electric current. Previous theories on the production of oxygen in deep-sea habitats are called into question by this electrochemical reaction, which takes place independently of photosynthesis.

Consequences For The Origins Of Life

Long-held theories regarding the origins of life on Earth are called into question by the finding of “dark oxygen” production in the deep oceans. It was formerly believed that the evolution of photosynthetic creatures was a prerequisite for the emergence of oxygen-breathing (or aerobic) life. This discovery, however, raises the possibility that deep-sea ecosystems may have had oxygen long before photosynthesis did. This finding forces scientists to reevaluate basic theories regarding the origin of aerobic life and may cause them to refocus their attention from surface settings to the deep ocean as a potential cradle for early life forms.

Future Paths For Research

The amount of oxygen produced by polymetallic nodules and how it affects deep-sea ecosystems require more research. Scientists are trying to figure out how this “dark oxygen” impacts marine life’s survival and dispersal in these low-light settings. Furthermore, given the documented persistence of “dead zones” in previously mined areas, research is needed to examine the possible long-term effects of deep-sea mining on these recently found oxygen sources. Subsequent investigations could concentrate on creating environmentally friendly mining techniques that maintain these essential oxygen-producing nodules while satisfying the increasing need for rare earth metals for green technology.