The preliminary, biologically baffling findings have been printed final 12 months within the journal Nature Geoscience. They got here from a number of expeditions to an space of the deep sea between Hawaii and Mexico, the place Prof Sweetman and his colleagues despatched sensors to the seabed – at about 5km (3.1 miles) depth.
That space is a part of an unlimited swathe of seafloor that’s lined with the naturally occurring metallic nodules, which kind when dissolved metals in seawater acquire on fragments of shell – or different particles. It is a course of that takes hundreds of thousands of years.
Sensors that the group deployed repeatedly confirmed oxygen ranges going up.
“I simply ignored it, Prof Sweetman instructed BBC Information on the time, “as a result of I would been taught that you just solely get oxygen by way of photosynthesis”.
Ultimately, he and his colleagues stopped ignoring their readings and set out as a substitute to know what was occurring. Experiments of their lab – with nodules that the group collected submerged in beakers of seawater – led the scientists to conclude that the metallic lumps have been making oxygen out of seawater. The nodules, they discovered, generated electrical currents that might cut up (or electrolyse) molecules of seawater into hydrogen and oxygen.
Then got here the backlash, within the type of rebuttals – posted on-line – from scientists and from seabed mining firms.
One of many critics, Michael Clarke from the Metals Firm, a Canadian deep sea mining firm, instructed BBC Information that the criticism was centered on a “lack of scientific rigour within the experimental design and knowledge assortment”. Principally, he and different critics claimed there was no oxygen manufacturing – simply bubbles that the tools produced throughout pattern assortment.
“We have dominated out that risk,” Prof Sweetman responded. “However these [new] experiments will present the proof.”
This may appear a distinct segment, technical argument, however a number of multi-billion pound mining firms are already exploring the potential of harvesting tonnes of those metals from the seafloor.
The pure deposits they’re concentrating on include metals important for making batteries, and demand for these metals is rising quickly as many economies transfer from fossil fuels to, for instance, electrical automobiles.
The race to extract these sources has brought about concern amongst environmental teams and researchers. Greater than 900 marine scientists from 44 nations have signed a petition, exterior highlighting the environmental dangers and calling for a pause on mining exercise.
Speaking about his group’s newest analysis mission at a press convention on Friday, Prof Sweetman mentioned: “Earlier than we do something, we have to – as finest as potential – perceive the [deep sea] ecosystem.
“I feel the proper resolution is to carry off earlier than we determine if that is the proper factor to do as a a worldwide society.”
