Scientists may have found that oxygen is being created without photosynthesis

Dark oxygen produced on the ocean floor by ancient microbes and lithium-ion batteries: a cry for a pause in the development of deep sea mining

In the last few years, a team of marine biologists went back to the places that were once mined and found no life. “And then a few hundred meters over to the left and right, where the nodules were intact, plenty of life.”

There is a lightless landscape of the Pacific Ocean floor and researchers think they’ve seen dark oxygen being created there.

The nodules may be a prospective source of battery ingredients, but Sweetman believes they could already be producing something quite different: oxygen. Typically, the element is generated when organisms photosynthesize, but light doesn’t reach 4,000 meters below the ocean’s surface. In a new paper Sweetman and his team at the Scottish Association for Marine Science suggest that the nodules could be driving a reaction that produces the dark oxygen from the sea.

“The conventional view is that oxygen was first produced around three billion years ago by ancient microbes called cyanobacteria and there was a gradual development of complex life thereafter,” said the director of the Scottish Association for Marine Science, Nicholas Owens, in the news release. We need a radical rethink due to the potential that there was an alternative source.

Researchers conducted tests on the seafloor and also collected samples to test aboveground, and they came up with the same result: that oxygen levels increased near the polymetallic nodules.

Polymetallic nodules contain metals such as manganese, nickel and cobalt, which can be used to make the lithium-ion batteries used in consumer electronics, appliances and electric vehicles.

For more than 10 years, Andrew Sweetman and his colleagues have been studying the ocean floor and its ecosystems, particularly in the Pacific’s Clarion-Clipperton Zone, an area littered with polymetallic nodules. As big as potatoes, these rocks contain valuable metals—lithium, copper, cobalt, manganese, and nickel—that are used to make batteries. They are a tempting bounty for deep-sea mining companies, which are developing technologies to bring them to the surface.

The argument is that the deep seabed needs to be protected from industrial exploitation. A petition has been signed by more than 800 marine scientists from 44 countries, calling for a pause in the development of deep sea mining.

Research suggests that the deep-sea mining missions that took place in the 70s and 80s may have had a negative effect on the marine life in the area.

“Where could aerobic life have begun?” was a question Andrew Sweetman, a professor with the Scottish Association for Marine Science, asked in a news release.

The same finding, however, was repeated in 2021, albeit using a different measurement approach. The scientists were assessing changes in oxygen levels inside a benthic chamber, an instrument that collects sediment and seawater to create enclosed samples of the seabed environment. The instrument allowed them to analyze oxygen consumption within the sample environment. Oxygen trapped in the chamber should have decreased over time as organisms in the water and sediment consumed it, but it did the opposite: Despite the dark conditions preventing any photosynthetic reactions, oxygen levels in the benthic chamber increased.

It is not known what the electric current is, whether the reaction is continuous, and if the oxygen production is significant enough to sustain an ecology.

There is an even bigger question, what if the polymetallic nodules gave birth to life on Earth? This is an exciting hypothesis that should be explored further according to Sweetman. It might even be possible that this could take place on other worlds, and be a potential source of alien life.

Some are questioning the findings with many unanswered questions. The biggest criticisms have come from within the seabed-mining world: Patrick Downes of the Metals Company, a seabed-mining company that works in deep water—the same waters Sweetman studied and that partly funded Sweetman’s research—says the results are the result of oxygen contamination from outside sources, and that his company will soon produce a paper refuting the thesis put forward by Sweetman’s group.