Dark oxygen made by deep sea 'batteries'

The discovery that lumps of metal on the seafloor produce oxygen raises questions over plans to mine the deep ocean.

British Broadcasting CorporationWatchHomeNewsSportBusinessInnovationCultureTravelEarthVideoLiveHomeNewsIsrael-Gaza WarWar in UkraineUS & CanadaUKUK PoliticsEnglandN. IrelandN. Ireland PoliticsScotlandScotland PoliticsWalesWales PoliticsAfricaAsiaChinaIndiaAustraliaEuropeLatin AmericaMiddle EastIn PicturesBBC VerifySportBusinessExecutive LoungeTechnology of BusinessWomen at the HelmFuture of BusinessInnovationTechnologyScience & HealthArtificial IntelligenceAI v the MindCultureFilm & TVMusicArt & DesignStyleBooksEntertainment NewsTravelDestinationsAfricaAntarcticaAsiaAustralia and PacificCaribbean & BermudaCentral AmericaEuropeMiddle EastNorth AmericaSouth AmericaWorld’s TableCulture & ExperiencesAdventuresThe SpeciaListEarthNatural WondersWeather & ScienceClimate SolutionsSustainable BusinessGreen LivingVideoLiveLive NewsLive SportHomeNewsSportBusinessInnovationCultureTravelEarthVideoLiveAudioWeatherNewslettersOxygen discovery defies knowledge of the deep oceanGetty ImagesUntil this discovery, it was believed that oxygen could not be produced without sunlightScientists have discovered “dark oxygen” being produced in the deep ocean, apparently by lumps of metal on the seafloor.

About half the oxygen we breathe comes from the ocean. But, before this discovery, it was understood that it was made by marine plants photosynthesising - something that requires sunlight.

Here, at depths of 5km, where no sunlight can penetrate, the oxygen appears to be produced by naturally occurring metallic “nodules” which split seawater - H2O - into hydrogen and oxygen.

Several mining companies have plans to collect these nodules, which marine scientists fear could disrupt the newly discovered process - and damage any marine life that depends on the oxygen they make.

“I first saw this in 2013 - an enormous amount of oxygen being produced at the seafloor in complete darkness,” explains lead researcher Prof Andrew Sweetman from the Scottish Association for Marine Science. “I just ignored it, because I’d been taught - you only get oxygen through photosynthesis.

https://www.bbc.com/news/articles/c728ven2v9eo

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