‘Dark oxygen’ sounds sexy and mysterious, but science rarely delivers on its amorous threats.
In this case, dark oxygen refers to oxygen made in the absence of sunlight, entirely skipping photosynthesis (which is responsible for most of what we breathe). Hard to find and tricky to study, dark oxygen has been found in a few places, one of which being deep underwater.
Finding trace levels of oxygen in the depths of the ocean changes what we thought we knew about the delicate and inaccessible ecosystem that keeps the aquatic food chain alive … but found it, we have, lurking around the valuable nodules desired by deep sea mining operations.
Headlines claim that textbooks will have to be rewritten and centuries of scientific beliefs have been upended.
Sweetman found himself at the centre of a media storm. Life changed overnight, he says – he even gets stopped on the street by people wanting a photograph with him. ‘It’s been very surreal,’ he says.
If the initial research is backed up by a future study, Sweetman will be etched into the next generation of textbooks. The story of early life has usually relied on the photosynthesis of microorganisms, particularly cyanobacteria. Somewhere around the 3 billion year mark, these simple organisms started making oxygen as they colonised warm, salty waters. This triggered the Great Oxidation Event. Since then, oxygen levels have varied but essentially, plants make it and we breathe it. When oxygen is found in the atmosphere of other planets, such as Mars, scientists always wonder if it has a biological source.
Dark oxygen probably doesn’t change the chapter titles on the story of Earth, but it might cause the renewable energy industry a headache.
The industry is worth between $8-16 trillion dollars of which about $2 billion is contained in polymetallic nodules.
In short, deep water is both the Wild West and a legal grey area dominated by nations such as China. Companies are diving for Wet Gold, so to speak, is to feed the renewable energy revolution.
The reason dark oxygen is controversial rather than cool is due to this deep sea rare earths mining industry.
‘Exploration in a region called the Clarion-Clipperton Zone – where deep-sea mining companies are eyeing metals resources like cobalt and nickel – uncovered ferromanganese nodules resting on the ocean floor … researchers suggested that the nodules may produce electric charges that spark electrolysis, generating oxygen and hydrogen.’
The creation of these nodules is a slow process taking millions of years while the deep sea is a fragile, poorly understood biological system that underpins Earth’s food chain.
Following the startling initial report, researchers are keen to find out more about how these trace levels of oxygen interact with life before deep-sea mining sucks it all up.
‘Our discovery of dark oxygen was a paradigm shift in our understanding of the deep sea and potentially life on Earth, but it threw up more questions than answers,’ said the head of the research team.
It’s no surprise that the strongest challengers to this research are deep-sea mining companies, including one that lodged a rebuttal to the initial research paper.
Popular Mechanics reports:
‘This research comes at a sensitive time, as the International Seabed Authority is still determining the rules and regulations of mining these resource-rich nodules. If these hunks of metal are producing trace amounts of oxygen vis seawater electrolysis, the damage to this already sensitive area could be severe.’
Following the 2024 paper, the CEO of the mining company said, ‘After decades of research using the same methods, no credible scientist has ever reported evidence of dark oxygen. Extraordinary claims require extraordinary evidence. We’re still waiting.’
‘All we are asking for is a little more time to go out and try to figure out what is going on,’ said Sweetman.
The real question is, will the answers make any difference?
With trillions of dollars of deep sea mining at stake, and an unstoppable renewable energy empire prowling around, it does not feel like dark oxygen is going to have a happy ending.
So far, 32 countries have thrown their support behind a moratorium on deep sea mining. Australia is not one of them.
Former Prime Minister Scott Morrison was announced as the strategic advisor at the Seafloor Minerals Fund. Morrison, along with Mike Pompeo, are involved in DYNE which has, according to The Sydney Morning Herald, invested millions in Pacific-based deep sea mining initiatives.
The US, in particular, is keen to fend off China’s dominating presence in the industry and what has been referred to as the militarisation of the ocean.
As The Age reported back in May, 2024:
‘Prospectors lobbying governments to open the deep sea to mining … argue that such high-yield metals could both accelerate the clean energy transition and shore up Western supply chains.’
Quoting an international environment lawyer, the article added, ‘…it was a bad look for a former Prime Minister to become involved in an industry where some players operate under “the guise of national security”, even as other countries argue for a global moratorium on deep sea mining until more is understood about the risks.’
We can all agree that it would fundamentally undermine the green energy revolution if it came at the expense of the deep ocean ecosystem and its elusive dark oxygen.
