Scientists Discover ‘Dark Oxygen’ Formed from Metals on the Seafloor

Researchers exploring the Pacific Ocean floor have discovered a new form of oxygen, termed “dark oxygen,” which challenges existing theories about how oxygen is produced on Earth.

Traditionally, it was believed that oxygen was generated exclusively through photosynthesis, a process requiring sunlight.

However, this recent discovery suggests that oxygen can also be produced in the absence of light, raising new questions about the origins of life.

The findings were published in Nature Geoscience on Monday, July 22 2024, by a team led by Andrew Sweetman from the Scottish Association for Marine Science in Oban, Scotland.

The researchers believe that “dark oxygen” is created by electrically charged minerals known as polymetallic nodules found on the seafloor.

These nodules, which vary in size from small particles to potato-sized, may function like “batteries in a rock,” using their electric charge to split seawater into hydrogen and oxygen through a process called seawater electrolysis.

“The conventional view is that oxygen was first produced by ancient microbes called cyanobacteria about three billion years ago, leading to the gradual development of complex life,” said Nicholas Owens, director of the Scottish Association for Marine Science. “The possibility of an alternative source of oxygen requires a radical rethink.”

Tests conducted on the seafloor and aboveground samples showed that oxygen levels increased near the polymetallic nodules. These nodules, which can generate up to 0.95 volts of electricity, with multiple nodules producing even higher voltages, may be responsible for this newly observed phenomenon.

This discovery could lead to significant revisions in our understanding of early Earth and the origins of aerobic life.