Scientists Prepare Deep-Sea Expedition to Investigate ‘Dark Oxygen’

A team of scientists has announced plans for a deep-sea expedition aimed at investigating their controversial discovery of “dark oxygen,” a potential new source of oxygen produced by metallic rocks on the ocean floor. This revelation could challenge longstanding assumptions about the origins of life on Earth, raising significant questions about the processes that sustain marine ecosystems.

The expedition follows research led by British marine ecologist Andrew Sweetman in 2024, which suggested that these metallic nodules might be generating oxygen through a process known as electrolysis. Sweetman and his team unveiled two specially designed landers at a press conference on March 12, 2024, capable of descending to depths of 11 kilometres (seven miles) in the Clarion-Clipperton Zone, a region located between Hawaii and Mexico.

These advanced landers will be equipped with sensors that measure seafloor respiration, a significant upgrade from previous missions. According to Sweetman, these devices can withstand pressures of up to 1,200 times that of Earth’s surface and are designed more like equipment used in space exploration than traditional oceanographic gear. The researchers aim to learn how these nodules could be contributing to oxygen production.

Critics have emerged, particularly from the deep-sea mining industry, which seeks to extract precious metals from these nodules. Some researchers have expressed skepticism regarding the initial findings, suggesting that the detected oxygen may simply be air bubbles trapped in the measuring instruments. Sweetman countered this claim by stating, “We’ve used these instruments over the last 20 years and every time we’ve deployed them, we’ve never had bubbles,” emphasizing the rigor of their testing procedures.

Environmental Concerns and Future Research

The debate over the existence of dark oxygen coincides with growing tensions surrounding regulations for the deep-sea mining industry, which poses potential risks to marine biodiversity. Sweetman’s 2024 study received funding from The Metals Company, a Canadian deep-sea mining firm that has since criticized his research. He noted, “If commercial mining goes ahead, then there will be quite widespread impacts,” highlighting the ecological significance of the nodules, which serve as habitats for diverse marine life.

Sweetman clarified that his goal is not to obstruct deep-sea mining but to gather essential data that could help mitigate its environmental impact. He stated, “We want to minimize the impacts as much as possible if mining does go ahead.”

In a collaborative effort, Matthias Haeckel, a biogeochemist at Germany’s GEOMAR Helmholtz Centre for Ocean Research, has also expressed interest in this research. Haeckel’s own studies have not indicated any evidence of oxygen production from the nodules. He will join Sweetman’s team on an upcoming research cruise at the end of this year, where they plan to compare methodologies and findings.

The upcoming research expedition, funded by the Japanese Nippon Foundation, is scheduled to take place in May 2024. Sweetman anticipates that results regarding dark oxygen production could be confirmed within 24 to 48 hours after the landers resurface. However, the broader findings may not be available until the ship returns in June, as additional analyses on land could take several months to complete.

As this expedition unfolds, it will not only test the hypothesis of dark oxygen but could also significantly influence the ongoing discussions about the future of deep-sea mining and its environmental implications.