Deep-sea metals may provide oxygen for life on ocean floor

Researchers say the polymetallic nodules that mining companies hope to extract from the deep sea floor could be a source of oxygen for the animals, plants and bacteria that live there.

The discovery of this “dark oxygen” could shake up negotiations Global rule-making body meets in Jamaica this month The International Seabed Authority (ISEA) is meeting to decide the future of deep sea mining.

The study was recently published in the journal Neurology. Nature Geoscience.

“This study is a really good example of how limited our current knowledge of the deep ocean is, and how much we could benefit from further scientific research,” said Diba Amon, a marine biologist from Trinidad and a postdoctoral researcher at the Benioff Ocean Initiative at the University of California, Santa Barbara.

The spotlight is on potato-sized rocks, or polymetallic nodules, scattered across the ocean floor that contain minerals such as cobalt and nickel, which are needed for green-energy batteries and technologies.

Companies such as Canada’s The Metals Corp. have been trying for years to convince international regulators to approve plans to mine these metal nodules in the Clarion Clipper Basin of the Pacific Ocean, a 4,500-mile stretch of ocean between Hawaii and Mexico.

The company claims that these metals are essential for building technologies that are not dependent on fossil fuels, and that mining will not only have minimal impact on the seafloor, but will be incomparable to the destruction of rainforests and human communities caused by land-based mining.

But environmentalists and oceanographers say driving large sampling machines on and around the pristine, little-known sea floor – sediments three to four miles below the surface – could have disastrous, unintended consequences. Lawmakers urge industry delays and bans It was born from excavating one of the last remaining “intact” ecosystems on Earth.

The new TMC-funded study suggests that the damage from mining in the region may be greater than anyone had imagined.

That’s because an international team of scientists has discovered that the precious nodules may be producing oxygen, enriching this dark, remote ecosystem with one of the most important elements for life.

Jeffrey Marlow, an assistant professor of biology at Boston University and one of the paper’s authors, said he and his team received funding from TMC to conduct baseline research on the environment, including sending what they call “benthos chambers” to the ocean floor.

The roughly 10-foot-tall structures, “think of them as upside-down boxes, or things that you stick into the ocean floor,” Marlow said. They’re watertight and airtight and contain instruments to measure the chemistry and composition of sediments.

The sampling method is pretty standard, he says: Scientists place a chamber on the ocean floor and measure the amount of oxygen lost, or lost, over a 48-hour period, which is a measure of the amount of life on the ocean floor, since animals use oxygen to breathe.

However, when they sent the chamber down for this analysis, they noticed that oxygen levels were increasing rather than decreasing.

Marlowe said he was certain the machine was faulty. They tried again with the same results.

“These benthic chamber experiments have been done all over the world for decades,” he says, “so the technology is all pretty well established.”

They spent days, then weeks, troubleshooting, he said.

“We had multiple ways of measuring, and we knew that none of them were failing. Ultimately, we were forced to conclude that oxygen was being produced.”

The researchers believe that on a chemical level, the nodules and the metals within them function like batteries.

“These rocks are made up of minerals, and the metals in those minerals are distributed unevenly throughout the rock,” he says. “Each of these metals and minerals can hold a charge in a slightly different way, so essentially this natural variation means that there’s a separation of charge, just like in a battery.”

This means there is enough voltage to split water into hydrogen and oxygen.

But not everyone is convinced or satisfied with the study’s conclusions.

TMC, which sponsored the study, sent a critique of the paper to the Times, saying the study was rejected by four scientific journals before being published in Nature, which the company described as “a journal that takes a strong stance against deep-sea mineral extraction.”

The journal’s public relations team did not respond to a request for comment, but the journal is generally regarded as one of the most prestigious and selective publications among scientists.

TMC also argued that the methodology was flawed and that the team’s findings were inconsistent with other studies conducted in the Clarion Clipper Zone but using different methods.

“Our failure to replicate the results with both methods suggests that the elevated oxygen levels are in fact a data artifact,” the company said in a statement. It added that it is “currently preparing a peer-reviewed paper to refute these claims.”

Bo Baerker Jorgensen, a microbiologist at Aarhus University in Denmark who was not involved in the study and is not on TMC’s payroll, said the research raised more questions than it answered.

“I don’t think this discovery is significant for understanding the ocean in general, or for deep-sea mining,” he said, describing the research as “a novel and very puzzling process, the mechanism of which is not yet clear.”

The study authors disputed the criticism, saying they were troubled by the findings but had thoroughly ruled out all other possibilities.

“We’ve been some of the harshest critics of this paper for a long time,” said Andrew Sweetman, leader of the Submarine Ecology and Biogeochemistry Research Group at the Scottish Institute for Marine Science and lead author of the paper. “For eight years I thought my sensors were faulty and discarded the data showing oxygen production. When I realised something might be going on, I tried to disprove it, but in the end I couldn’t.”

He welcomed further research on the subject and urged other scientists to conduct further investigations.

“After publishing this paper, we were contacted by other researchers with similar data sets that also showed evidence of dark oxygen production, but they thought their instruments were faulty and discarded it,” he said.