Serendipitous discovery of “dark oxygen” sparks controversy and new expeditions
Big if true: A team of researchers led by Andrew Sweetman made the serendipitous discovery last year that metallic rocks on the ocean floor are producing oxygen. Now, the same team is looking to confirm that discovery and finally put an end to a growing controversy amid the scientific community.
Professor Andrew Sweetman and his colleagues set out to measure seafloor respiration but instead stumbled upon a hidden ecosystem capable of producing oxygen. The most crucial element for life on Earth is typically generated through photosynthesis, a process that requires plants and sunlight. However, the “dark oxygen” discovered by Sweetman’s team operates without either. Scientists are still debating whether this “shocking” finding stems from a genuine phenomenon or is merely the result of faulty equipment or measurement errors.
Sweetman is now spearheading a new research project to verify the dark oxygen discovery, with three expeditions planned to closely investigate the metallic nodules that serve as natural “geobatteries.” The endeavor faces significant challenges, including skepticism from the scientific community and opposition from mining corporations with vested interests in the seabed.
Gerard Barron, CEO of The Metals Company, expressed doubt about the findings, stating that no “credible scientist” has ever found evidence of dark oxygen production using the same methods employed by Sweetman’s team. “Extraordinary claims require extraordinary evidence. We’re still waiting,” Barron said.
Barron’s company funded the research that led to the discovery of dark oxygen but is now working to discredit Sweetman’s findings. The mining company’s primary interest lies in exploiting the metallic nodules to extract raw materials. As the world transitions to environmentally friendly energy sources, the demand for these precious metals is expected to surge. A potentially groundbreaking discovery like anaerobic oxygen production could pose a significant obstacle to these mining efforts.
Sweetman has faced criticism from other scientists as well. Nature Geoscience, the scientific journal that published his work in 2024, may even decide to retract the paper.
Sweetman described the media storm surrounding the discovery as life-changing, noting that it has been “extremely tiring” to navigate. Despite the challenges, the scientist is committed to providing definitive proof that dark oxygen production from the ocean floor is a legitimate phenomenon.
The first expedition is slated to depart from San Diego in January 2026. The research team will be using a $2.4 million grant from The Nippon Foundation and will deploy custom-built probes designed to operate 12,000 meters below sea level. These probes will gather new data, collecting samples of water and seafloor sediments in an effort to confirm the dark oxygen theory once and for all.
