https://phys.org/news/2025-03-dark-oxygen-deep-sea-discovery.html Phys.org Topics * Week's top * Latest news * Unread news * Subscribe [ ] Science X Account [ ] [ ] [*] Remember me Sign In Click here to sign in with or Forget Password? Not a member? Sign up Learn more * Nanotechnology * Physics * Earth * Astronomy & Space * Chemistry * Biology * Other Sciences * Medical Xpress Medicine * Tech Xplore Technology [INS::INS] * * share this! * 48 * Tweet * Share * Email 1. Home 2. Earth 3. Earth Sciences 1. Home 2. Earth 3. Environment * * * --------------------------------------------------------------------- March 17, 2025 The GIST Editors' notes This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: fact-checked peer-reviewed publication reputable news agency proofread 'Dark oxygen': a deep-sea discovery that has split scientists Polymetallic nodules and an abyssal urchin Polymetallic nodules and an abyssal urchin. Could lumpy metallic rocks in the deepest, darkest reaches of the ocean be making oxygen in the absence of sunlight? Some scientists think so, but others have challenged the claim that so-called "dark oxygen" is being produced in the lightless abyss of the seabed. The discovery--detailed last July in the journal Nature Geoscience --called into question long-held assumptions about the origins of life on Earth, and sparked intense scientific debate. The findings were also consequential for mining companies eager to extract the precious metals contained within these polymetallic nodules. Researchers said that potato-sized nodules could be producing enough electrical current to split seawater into hydrogen and oxygen, a process known as electrolysis. This cast doubt on the long-established view that life was made possible when organisms started producing oxygen via photosynthesis, which requires sunlight, about 2.7 billion years ago. "Deep-sea discovery calls into question the origins of life," the Scottish Association for Marine Science said in a press release to accompany the publication of the research. Delicate ecosystem Environmentalists said the presence of dark oxygen showed just how little is known about life at these extreme depths, and supported their case that deep-sea mining posed unacceptable ecological risks. Seabed mining Infographic showing the three different types of seabed zones being explored for potential mining. "Greenpeace has long campaigned to stop deep sea mining from beginning in the Pacific due to the damage it could do to delicate, deep sea ecosystems," the environmental organization said. "This incredible discovery underlines the urgency of that call". The discovery was made in the Clarion-Clipperton Zone, a vast underwater region of the Pacific Ocean between Mexico and Hawaii of growing interest to mining companies. Scattered on the seafloor four kilometers (2.5 miles) beneath the surface, polymetallic nodules contain manganese, nickel and cobalt, metals used in electric car batteries and other low-carbon technologies. The research that gave rise to the dark oxygen discovery was partly funded by a Canadian deep-sea mining business, The Metals Company, that wanted to assess the ecological impact of such exploration. It has sharply criticized the study by marine ecologist Andrew Sweetman and his team as plagued by "methodological flaws". Michael Clarke, environmental manager at The Metals Company, told AFP that the findings "are more logically attributable to poor scientific technique and shoddy science than a never before observed phenomenon." [INS::INS] Scientific doubts Sweetman's findings proved explosive, with many in the scientific community expressing reservations or rejecting the conclusions. Deep-sea mining Exploration areas licensed by the International Seabed Authority, including to The Metals Company, a Canadian company. Since July, five academic research papers refuting Sweetman's findings have been submitted for review and publication. "He did not present clear proof for his observations and hypothesis," said Matthias Haeckel, a biogeochemist at the GEOMAR Helmholtz Center for Ocean Research in Kiel, Germany. "Many questions remain after the publication. So, now the scientific community needs to conduct similar experiments etc, and either prove or disprove it." Olivier Rouxel, a geochemistry researcher at Ifremer, the French national institute for ocean science and technology, told AFP there was "absolutely no consensus on these results". "Deep-sea sampling is always a challenge," he said, adding it was possible that the oxygen detected was "trapped air bubbles" in the measuring instruments. He was also skeptical about deep-sea nodules, some tens of millions of years old, still producing enough electrical current when "batteries run out quickly". "How is it possible to maintain the capacity to generate electrical current in a nodule that is itself extremely slow to form?" he asked. When contacted by AFP, Sweetman indicated that he was preparing a formal response. "These types of back and forth are very common with scientific articles and it moves the subject matter forward," he said. Journal information: Nature Geoscience (c) 2025 AFP Citation: 'Dark oxygen': a deep-sea discovery that has split scientists (2025, March 17) retrieved 20 March 2025 from https:// phys.org/news/2025-03-dark-oxygen-deep-sea-discovery.html This document is subject to copyright. Apart from any fair dealing for the purpose of private study or research, no part may be reproduced without the written permission. 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Some propose these nodules generate electrical currents that split seawater into hydrogen and oxygen, challenging the belief that photosynthesis was the sole origin of oxygen production. However, many researchers question the findings, citing potential methodological flaws and lack of consensus. The discovery also raises concerns about the ecological risks of deep-sea mining. This summary was automatically generated using LLM. Full disclaimer Let us know if there is a problem with our content Use this form if you have come across a typo, inaccuracy or would like to send an edit request for the content on this page. For general inquiries, please use our contact form. For general feedback, use the public comments section below (please adhere to guidelines). 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