‘Dark oxygen’ discovered under sea raises risks for deep-sea mining deals

The discovery of “dark oxygen” in the ocean’s abyss is raising stakes in negotiations over whether to mine the seabed for battery materials — and how to protect sensitive marine life in the process.

Rules for deep-sea mining were at the center of negotiations during the annual meetings of the International Seabed Authority (ISA) in Kingston, Jamaica, which ended on Friday. A mining company has already said that, after the meetings end, it will present the first request to explore seabed minerals.

The company’s plans have sparked a rush to establish rules before any mining begins. But there is so little humans know about the deep sea that a growing chorus of scientists, advocates and policymakers is sounding the alarm that there could be serious and unforeseen consequences. Evidence of mysterious “dark oxygen” from the bottom of the abyssal sea was published in a prestigious journal in July. It raises new questions about the risks that mining can pose to life at the bottom of the ocean, which scientists are still trying to understand, and is amplifying calls for a moratorium on mining.

“Today we are at a crossroads. The decisions we make in this Assembly will shape the future health and productivity of our oceans for generations to come,” said Palau President Surangel Whipps Jr. he said in its opening declaration during the ISA Assembly on July 29th. “Whether it’s undiscovered biodiversity that could reveal a cure for cancer, or the recent discovery last week that ‘dark oxygen’ is produced deep in the ocean by nodules on the sea floor, we have a lot to learn about depths of the ocean. seabed and the vital role it plays for our planet.”

Oxygen is a product of photosynthesis. Plants and plankton use sunlight, water and carbon dioxide to create sugars and oxygen. This is what makes the discovery of dark oxygen at the bottom of the abyss, with depths between 3,000 and 6,500 meters (9,842 and 21,325 feet), so incredible – what is down there that can produce oxygen without sunlight? A article published in the magazine Natural Geosciences Last week suggests that there is a completely different and previously unknown process for producing oxygen on Earth, and it comes from probably the most unexpected places.

The findings were so surprising that the authors themselves were initially skeptical of their own data. They intended to document the amount of oxygen that deep-sea organisms consume at the bottom of the Pacific Ocean, in a way area between Hawaii and Mexico that companies are eyeing mining. They sent probes about 4,000 meters deep to make measurements in spaces closed to external currents that would normally bring oxygen from the sea surface. The method is like placing a can upside down at the bottom of a swimming pool and documenting what happens inside it. They expected to see oxygen levels drop over time in the enclosed area, but documented the opposite. Thinking something must be wrong with their sensors, they changed the equipment and still continued to get similar readings. When they lifted the landers, the oxygen bubbled.

They still don’t know for sure as oxygen is produced. But they have a hypothesis. Polymetallic nodules rich in nickel, copper, cobalt, iron and manganese are scattered across the seafloor – exactly what mining companies are interested in exploring and have even described as “batteries on a rock.” They may be able to produce enough electrical charge to split seawater, releasing oxygen through electrolysis.

There is much more research to be done to test this hypothesis. The paper’s authors were taking oxygen readings and not looking for higher levels of hydrogen – which would be expected to see if these rock batteries are actually capable of splitting water. They brought some nodules to earth to see if they could replicate the process in a laboratory. This is how they were able to rule out other possibilities like microbes producing dark oxygen. Once again, the results were surprising.

“I approached the problem from the perspective of, you know, there’s no way these things have this high voltage… and the readings were off the chart,” says Franz Geiger, one of the paper’s authors and a professor. in physical chemistry at Northwestern University.

The team documented voltages as high as about 950 millivolts – just shy of the 1.3 to 1.5 volts that would be needed to split seawater or at least achieve an oxygen-producing half-reaction – called an evolution reaction. of oxygen. In the ocean, where there are vast networks of nodules, the voltage could be high enough to trigger these reactions, they hypothesize.

The research was funded in part by The Metals Company (TMC), the same company that plans to apply for a license to begin deep-sea mining. The company claims to be conducting “one of the most comprehensive deepwater research programs in history,” spending more than $200 million on environmental assessments. But now, they are disputing the conclusions of the paper published in Natural Geosciences last month – sparking a row with researchers whose findings may not coincide with the company’s claim that mining in the ocean abyss would be a less harmful alternative to mining on land.

When On the edge We contacted the company, they recommended us a declaration was released saying he was “surprised to see the questionable paper” Published. The company says it is still “preparing a comprehensive rebuttal,” but so far it has questioned the researchers’ “flawed” methods, in part because the data was “collected under conditions not representative” of the area of ​​the seabed where it is located. interested in mining. It also says that the article contradicts other studies and was rejected by other journals.

The research team keeps up its work. “We were the worst critics of this newspaper for a long time. For eight years I dismissed the data showing oxygen production, thinking my sensors were faulty. As soon as we realized something might be going on, we tried to disprove it, but in the end we just couldn’t,” says lead author Andrew Sweetman, professor at the Scottish Marine Science Association, in his own paper. declaration responding to The Metals Company.

Dark Oxygen has already caused a sensation in Kingston, say observers who have attended ISA meetings with advocacy groups and intergovernmental delegations. On the edge. Delegations representing several countries mentioned the investigation in their opening statements and the investigation is also discussed in negotiating rooms and at side events. “It also came up a lot along the corridors,” says Pradeep Singh, an ocean governance expert and fellow at the Sustainability Research Institute at the Helmholtz Center Potsdam.

Unsurprisingly, this is spurring calls to pump the brakes on mining. “The meaning [of this research] cannot be overestimated,” says David Santillo, marine biologist and senior scientist at Greenpeace Research Laboratories based at the University of Exeter. Greenpeace is one of the environmental groups that opposes deep-sea mining. “It is clear that it will also have implications for natural systems and processes on which not only deep-sea ecosystems depend, but on which the entire planet depends. We know the value and importance of oxygen as an element on Earth”, says Santillo.

Until here, 32 countries have expressed support for an outright ban, moratorium, or “preventative pause” on deep-sea mining, either until there are rules in place to prevent unnecessary harm, or until there is a better understanding of what mining can disrupt. This includes five new countries that joined the cause during this year’s ISA meeting.

The ISA missed a key deadline last year to draw up rules – two years after the island nation of Nauru left everyone nervous by advertising which would sponsor The Metals Company’s deep-sea mining aspirations. This is what allows TMC to now apply for a mining license.

Whether the ISA will give the TMC the green light if it is implemented this year is another story. Although it missed the initial deadline, ISA set an aspiration Timeline to implement rules by 2025. The ISA Council also released language in last year’s negotiations, saying commercial mining should not move forward until those rules were established, although that is not necessarily a legally binding decision. Therefore, there is still an effort to establish a more official moratorium and also to establish a more general conservation policy under the ISA for the protection of marine environments.

ISA also voted a new secretary general on Friday, replacing the one who faced accusations in getting very cozy with mining companies with an oceanographer who will become the first scientist to hold the position. For now, it appears there is still a lot of disagreement among delegates about what the rules should be for the ISA to reach its 2025 target, observers say. On the edge. “They are really far apart on the question of who is going to pay for the damages if this happens? How much liability would the damage incur? Would they simply be forced to clean up the mess, if that was even possible? says Matthew Gianni, co-founder of the Deep Sea Conservation Coalition, which is now calling for a moratorium.

Geiger, the study’s author, is not convinced that the world can avoid deep-sea mining forever, especially as electric vehicles and renewable energy increase demand for battery materials. “The materials are necessary, there is absolutely no doubt about that. Therefore, we may be forced, sooner or later, to take this step as a society. We hope this work informs where, when and how often to do this with minimized impact on the ecology down there,” he says.

“It’s not like you can wait 100 million years and have these nodules grow back. Once you take them off, they disappear.”