The discovery that oxygen is being generated by a certain type of metal found on the seabed of the Pacific Ocean has opened the door to a broader debate about its future.
Dubbed “dark oxygen”, it is created in extremely hostile conditions at 4,000 metres below the water's surface by sea floor clusters of metals known as polymetallic nodules. These clusters contain metals such as cobalt, manganese and nickel, which are found in lithium-ion batteries used in everything from vapes to laptops, from mobile phones to, perhaps most crucially, electric cars.
It could mean that damage to the ocean floor through mining operations is a cruelly ironic consequence of the drive to electrify transport to reduce the threat of climate change.
Cobalt can be worth more than $30,000 per tonne, while nickel is worth about half as much, although these figures fluctuate significantly as the balance between demand and supply changes. An electric car battery can contain, for example, up to 50kg of nickel worth about $750, along with several kilograms of cobalt.
Deep-sea mining
Many environmental organisations, including Greenpeace and WWF, oppose deep-sea mining, while, according to figures published by the Deep Sea Conservation Coalition (DSCC), an organisation under which more than 120 NGOs and other associations operate, 27 nations support a precautionary pause, a moratorium or a ban.
Among them is Britain, which in October said that it would not “sponsor or support the issuing of any … [exploitation] licences until sufficient scientific evidence is available to assess the potential effect of deep-sea mining activities on marine ecosystems and strong, enforceable environmental regulations, standards and guidelines have been developed and adopted”.
Dr John Childs, a senior lecturer at Lancaster University in the UK and an editorial board member of Extractive Industries and Society, said that deep-sea mining “is being offered as one of the solutions to the anticipated need to build the green-energy infrastructures of the future”.
However, he cautioned that it could not happen without “a number of significant social and ecological trade-offs”.
“There are a huge number of potential ecological harms at play,” he said. “The potential destruction of ecosystems that are home to as-yet undiscovered microorganisms, the creation of sediment plumes and noise pollution from deep-sea mining machinery present major concern for deep-sea environments, habitats and fauna.”
A senior figure from the DSCC told The National that deep-sea mining “threatens to destroy the deep sea, its ecosystems and species before we even have a chance to understand them”.
“In particular, it is currently unknown how the removal or smothering of these nodules from deep-sea mining operations and the associated sediment plumes could influence sea floor oxygen production and what the impacts on deep-sea life and processes, including carbon cycling, could be,” said Travis Aten, communications manager with the DSCC.
“These findings underscore the importance of furthering independent deep-sea scientific research across the globe to inform decision-making and emphasise the necessity for a more cautious and informed approach to deep-sea mining.”
“Understanding and conserving these processes is crucial before destructive activities such as deep-sea mining are allowed to proceed. A moratorium is needed,” said Mr Aten.
The Metals Company, who partly funded the research in the Nature Geoscience journal, took to social media on Tuesday to criticise its findings.
“The methodology and findings raise serious concerns about the validity of their data and conclusions,” it posted on X.
Conflicts of interest
The sector is regulated by the International Seabed Authority (ISA), a UN-mandated organisation that manages seabed mineral resources outside of national jurisdictions.
Trust in the ISA has “drastically eroded”, according to the DSCC, which states that there are conflicts of interest over links to mining contractors.
The regulatory body is in the middle of a leadership battle, with the incumbent secretary general, Michael Lodge, a British barrister, being challenged by a Brazilian oceanographer and administrator, Leticia Carvalho, who is keen for there to be tougher environmental safeguards.
The election of the secretary general is scheduled for the ISA’s forthcoming assembly, which runs from July 29 to August 2, and some reports have indicated that the outcome may determine whether the floor of the Pacific Ocean is mined.
So far, according to figures published by Greenpeace, the ISA has issued 31 deep-sea mining exploration contracts covering more than 1.5 million square kilometres in total. Just over half of the contracts involve the CCZ.
Following exploration, companies may apply to carry out commercial mining.
The Metals Company, one firm with an exploration contract, has already held trials in which thousands of nodules have been lifted from the sea floor.
Describing itself as an explorer of “lower-impact battery metals from polymetallic nodules”, the company aims, it states online, to “supply metals for the clean energy transition with the least possible negative environmental and social impact”.
The Metals Company, which is a partner of three Pacific island states, Tonga, Nauru and Kiribati, says that it also has an ambition to “accelerate the transition to a circular metal economy”.
It said last year that it expected to submit an application for commercial exploitation in the second half of in 2024 to begin mining operations in the fourth quarter of 2025.
While The Metals Company is keen to push ahead, Dr Childs said that investors and insurers were being put off the sector “by the high levels of risk”.
“Just look at the recent news that major insurers like Zurich are refusing to underwrite deep-sea mining,” he said. “Increasingly policy is following the science, which is recommending nothing less than a total pause in the push towards commercial extraction, at the very least until more is known about this still understudied environment.”
As commercial interests square up to environmental campaigners and many governments, it remains unclear whether the deep sea will become a vital source of metals and minerals for the energy transition – or will be left pristine for eternity.
Incredible discovery
The existence of dark oxygen raises questions about where aerobic life – life that depends on oxygen – may have started, researchers behind the study in Nature Geoscience say.
“For aerobic life to begin on the planet, there had to be oxygen and our understanding is that the Earth's oxygen supply began with photosynthetic organisms. But we now know that there is oxygen produced in the deep sea, where there is no light,” one of the researchers, Prof Andrew Sweetman, from the Scottish Association for Marine Science, said in an online statement.
The region where the dark oxygen research was carried out, the Clarion-Clipperton Zone, a large area of the Pacific between Hawaii and Mexico, is a prime area for deep-sea mining because of the heavy presence of metallic nodules.
