Dark Oxygen Discovered in Deep Ocean Environments

by Ayelen Flores Ruiz, age 14

Researchers exploring the Pacific Ocean have discovered what they call “dark oxygen,” created in the absence of sunlight. This discovery, found in deep ocean environments where sunlight cannot reach, raises new questions about how oxygen can be produced without photosynthesis.

Photosynthesis occurs when plants use sunlight, water, and carbon dioxide to create sugars and oxygen. Scientists previously believed photosynthesis was the only way to produce oxygen. However, this discovery challenges that theory. Andrew Sweetman, a professor from the Scottish Association for Marine Science, led the team that found the "dark oxygen." He said, “I think we therefore need to revisit questions like: Where could aerobic life have begun?”

Although it's not yet clear how oxygen is created in deep, dark environments, researchers believe it might be connected to electrically charged minerals on the ocean floor known as polymetallic nodules. These nodules, which can vary in size up to that of a potato, may act like batteries, generating electrical charges that break down seawater and release oxygen. By linking multiple nodules together, researchers hypothesize they could produce higher voltages and increase oxygen levels. Tests conducted on the ocean floor have shown oxygen levels rising near these nodules.

Polymetallic nodules are composed of metals like manganese, nickel, and cobalt, which are also used to produce lithium-ion batteries for electronics. Franz Geiger, a chemistry professor at Northwestern University, noted, “There may be enough polymetallic nodules in an area of the Pacific Ocean called the Clarion-Clipperton Zone to meet global energy demands for decades.” However, he cautioned that deep-sea mining must be done carefully to avoid depleting oxygen that marine life depends on. Geiger also pointed out that previous deep-sea mining missions in the 1970s and '80s damaged marine ecosystems. He said, “A few years ago, a team of marine biologists revisited areas that were mined 40 years ago and found essentially no life.”

Researchers plan to continue testing the polymetallic nodules to understand how oxygen is created in these environments. While these nodules could be valuable for energy production, there is a real danger that large-scale mining could harm ocean ecosystems. Sustainable mining practices must be developed to balance human needs with the protection of marine life.

[Source: NPR]