'Ground-breaking' dark oxygen discovery 13,000 feet below ocean's surface has scientists re-thinking origins of life

For as long as mankind has been around, it has been believed that sunlight is a necessity for oxygen to be produced, and it's all we've ever known.

Well, that is until now.

More than 10 times as deep as the Empire State Building is tall - or 600ft deeper than the Titanic wreckage - a natural ‘geobattery' has been discovered, lying around 13,100ft deep on the sea bed of the Pacific Ocean.

Ocean scientist Andrew Sweetman was the one who made the discovery of oxygen being produced in complete darkness on the seafloor.

It has been discovered that oxygen has been produced on the sea floor. (Getty Stock Image)

Speaking to the Scottish Association for Marine Science (SAMS), he said: “​In my opinion, this is one of the most exciting findings in ocean science in recent times.

“The discovery of oxygen production by a non-photosynthetic process requires us to rethink how the evolution of complex life on the planet might have originated.

"The conventional view is that oxygen was first produced around three billion years ago by ancient microbes called cyanobacteria and there was a gradual development of complex life thereafter."

Sweetman continued: "The potential that there was an alternative source requires us to have a radical rethink.”

But while the world is only just finding out about this, Sweetman actually first stumbled upon it more than a decade ago - back in 2013.

A species of sea cucumber called amperima sp. can be found deep down on the seabed. (Craig Smith and Diva Amon, ABYSSLINE Project)

At the time, he initially thought there was a problem with his monitoring equipment, because oxygen can't be produced in the pitch dark of the ocean's floor... can it?

He travelled to an area dubbed the Clarion-Clipperton zone - originally to assess the possible impacts of deep-sea mining - another three times and his 'faulty' equipment recorded oxygen levels each time.

The area spans 1.7 million square miles between Hawaii and Mexico.

Sweetman said: "I basically told my students, just put the sensors back in the box. We’ll ship them back to the manufacturer and get them tested because they’re just giving us gibberish."

Polymetallic nodules containing metals such as nickel, manganese and cobalt - which are required to produce lithium-ion batteries for electric vehicles and mobile phones, produce 'dark oxygen'. (Camille Bridgewater/Northwestern University)

The company got back to the SAMS professor, who led the seafloor ecology and biogeochemistry group, informing him that they were in fact working - which meant only one thing.

So what is creating this 'dark oxygen'?

It was uncovered as his team extracted polymetallic nodules that contained metals such as nickel, manganese and cobalt - which are required to produce lithium-ion batteries for electric vehicles and mobile phones.

They were found to be carrying a strikingly high electric charge that could lead to seawater splitting into hydrogen and oxygen - a process called seawater electrolysis.

In order for that to happen you would need around the same voltage of your typical AA battery, which is 1.5 volts - but Sweetman's research teams analysed multiple nodules with readings of up to 0.95 volts on the surfaces of some of them.

A species called Relicanthus sp. was discovered in the Clarion-Clipperton Zone. (Craig Smith and Diva Amon, ABYSSLINE Project)

This meant that that it would be possible for significant voltages to occur when they are clustered together.

The professor now believes mankind has to revisit the question to how life began.

He added: “For aerobic life to begin on the planet, there had to be oxygen and our understanding has been that Earth’s oxygen supply began with photosynthetic organisms.

"But we now know that there is oxygen produced in the deep sea, where there is no light. I think we therefore need to revisit questions like: where could aerobic life have begun?”