‘Dark Oxygen’ Deep in Pacific Ocean May Force Us to Rethink Origins of Life | Oceans

In the pitch black depths of the Pacific Ocean, scientists have discovered that oxygen is produced not by living organisms but by strange potato-shaped metal lumps that release about as much electricity as AA batteries.

The surprising discovery could have many potential implications and may even require a rethink of how life first emerged on Earth, the researchers who conducted the study said Monday.

It was thought that only living organisms such as plants and algae were able to produce oxygen through photosynthesis – which requires sunlight.

But four kilometers (2.5 miles) below the surface of the Pacific Ocean, where sunlight cannot reach, tiny mineral deposits called polymetallic nodules have been recorded producing so-called dark oxygen for the first time.

The discovery was made in the Clarion-Clipperton Zone (CCZ), a Hawaiian plain that stretches between Hawaii and Mexico, where mining companies plan to begin harvesting the nodules.

The lumpy nodules — often called “batteries in rock” — are rich in minerals such as cobalt, nickel, copper and manganese, all of which are used in batteries, smartphones, windmills and solar panels.

An international team of scientists has sent a small ship to the bottom of the Clarion-Clipperton Zone with the aim of finding out how mining might affect the strange and poorly understood animals that live where light does not reach.

“We were trying to measure the rate at which the seafloor was consuming oxygen,” Andrew Sweatman, lead researcher on the study from the Scottish Association for Marine Science, told AFP.

To do this, they used a device called a benthic chamber, which collected a large amount of sediment.

The amount of oxygen trapped in the chamber “usually decreases as it is consumed by organisms as they breathe,” Sweetman said.

But this time the opposite happened, the amount of oxygen increased. This was not supposed to happen in complete darkness where there is no photosynthesis.

This was so shocking that the researchers initially thought their underwater sensors might be broken. So they brought some nodes back to their ship to repeat the test. And again, the oxygen level increased.

Then they noticed how the nodules carried an amazing electrical charge.

“Surprisingly, we found a high voltage, almost as high as that of a AA battery,” on the surface of the nodules, Sweatman said. This charge can split seawater into hydrogen and oxygen in a process called seawater electrolysis, the researchers said.

This chemical reaction occurs at about 1.5 volts – roughly equivalent to the charge of an AA battery.

“This discovery was one of the most exciting results in ocean science in recent times,” said Nicholas Owens, director of the American Oceanographic Society.

The discovery of oxygen produced outside of photosynthesis “requires us to rethink how complex life on the planet evolved,” he added.

“The conventional view is that oxygen was first produced about 3 billion years ago by ancient microbes called cyanobacteria, and there was a gradual evolution of complex life after that,” Owens said.

The team’s discovery showed that “life may have begun somewhere other than Earth,” Sweetman said.

“And if this process is happening on our planet, could it help generate oxygen-rich habitats on other ocean worlds like Enceladus and Europa and provide the opportunity for life?” he said.

the study, Published in Nature GeoscienceThe project was partly funded by Canada’s The Metals Company, which aims to begin mining nodules in the Clarion-Klint Zone next year.