Above photo: A team of international scientists has found that oxygen is being produced in complete darkness approximately 4,000 meters below the ocean’s surface. Chaluk | Istock | Getty Images.
Potato-shaped metallic nodules deep under the Pacific Ocean produce oxygen in complete darkness.
The discovery of “dark oxygen” raises questions about the origins of life on Earth and the potential impact of deep-sea mining on marine ecosystems.
The discovery of “dark oxygen”, oxygen produced deep under the surface of the sea, is shining a light on the potential risks of deep-sea mining for metals and minerals. There has already been great controversy over plans to approve deep-sea mining activities at the international level, to meet the growing demand for critical minerals, and the recent discovery demonstrates just how little we know about marine ecosystems.
An international team of researchers recently discovered that oxygen is being made by potato-shaped metallic nodules deep under the surface of the Pacific Ocean. In July, their findings, which throw into dispute the concepts of oxygen production, were published in the Nature Geoscience journal. The discovery could lead to a reconsideration of the origins of complex life on Earth.
The findings from a team of researchers led by Professor Andrew Sweetman at the U.K.’s Scottish Association for Marine Science, show that oxygen is being produced at around 4,000 metres below the surface of the ocean in complete darkness. This contradicts previous scientific assumptions that only living organisms, including plants and algae, can use energy to create oxygen through photosynthesis, using sunlight for the reaction.
Sweetman explained, “For aerobic life to begin on the planet, there had to be oxygen and our understanding has been that Earth’s oxygen supply began with photosynthetic organisms.” He added, “But we now know that there is oxygen produced in the deep sea, where there is no light. I think we therefore need to revisit questions like: where could aerobic life have begun?”
The team made the discovery while conducting fieldwork between Hawaii and Mexico to assess the potential effects of deep-sea mining. Samples of nodules from the seabed in the Clarion-Clipperton Zone were found to contain a “very high” electric charge, which could support seawater electrolysis to split seawater into hydrogen and oxygen. Sweetman says that these nodules appear to be “effectively batteries in a rock”.
The new understanding of how oxygen is produced suggests the need for greater research, with a focus on the largely unexplored seabed. It also demonstrates how little we know about the undersea ecosystem and calls into question whether plans for deep-sea mining should go ahead. Many argue that we need to launch deep-sea mining operations to provide the critical minerals needed to power a global green transition, to diminish the effects of climate change. However, many environmentalists and scientists are concerned about launching invasive undersea activities without a full understanding of the potential environmental impact of deep-sea mining. Although deep-sea mining could provide a much-needed supply of the minerals needed for renewable energy equipment, electric vehicle batteries and clean technologies, it could create other environmental issues in the future.
The International Seabed Authority (ISA), the U.N. regulator that oversees deep-sea mining, is currently in the process of developing mining regulations, as more countries and companies show interest in developing new projects. There is an abundance of potato-sized nodules of critical minerals, including cobalt, nickel, copper, and manganese, sitting on the bottom of the seafloor, which many see as vital for fuelling a green transition. In January, Norway became the first country to approve the practice of deep-sea mining for critical minerals. However, it will not immediately launch new mining projects, instead, the government will assess proposals from mining companies on a case-by-case basis for license approval. The likelihood of new deep-sea mining operations commencing in the coming years has put pressure on the ISA to develop international mining regulations to ensure the protection of the seabed and marine life.
However, there has been great controversy over the ISA leadership in recent months, as the current ISA secretary general, Michael Lodge, battles against his opponent, Leticia Carvalho, for the next term in the role. Whoever takes the position for the next term will have significant input on deep-sea mining regulations. While Lodge strongly supports the establishment of regulations to allow for project development, Carvalho believes that more time is needed to understand the potential implications of deep-sea mining before appropriate regulations can be established. Supporters of each of the candidates have accused the other side of attempting to influence the outcome of the election by offering to pay for travel costs for delegates and pay delegations’ past-due membership fees. As countries in arrears are not permitted to vote, this could influence the outcome.
There is already scrutiny over the ISA structure, following several complaints about the current leadership and the upcoming election for a secretary general. The ISA is responsible for ensuring the protection of the undersea ecosystem, with some member states that would benefit from new mining activities and others who fear the impact of mining on their seas and land. The recent discovery of “dark oxygen” puts greater pressure on the ISA to conduct further research in the field to gain a better understanding of the potential impact of deep-sea mining and potentially halt any new projects until they are more certain of the implications.