Scientists have discovered that in the pitch black depths of the Pacific Ocean, oxygen is produced not by living organisms but by a strange, potato-shaped chunk of metal that emits roughly the same amount of electricity as a AA battery.
The surprising discovery has many potential implications and may even force us to rethink how life first emerged on Earth, the researchers who conducted the study said on Monday.
Until now, it was thought that only organisms such as plants and algae could produce oxygen through photosynthesis, which requires sunlight.
But 4 kilometers (2.5 miles) below the surface of the Pacific Ocean, where sunlight does not reach, Polymetallic nodules The production of so-called dark oxygen has been recorded for the first time.
The discovery occurred in the Clarion Clipperton Zone (CCZ), an abyssal plain between Hawaii and Mexico where mining companies plan to begin extracting nodules.
Nicknamed “batteries in rocks,” these chunks of rock are rich in metals such as cobalt, nickel, copper and manganese, which are used in batteries, smartphones, wind turbines and solar panels.
An international team of scientists has sent a small vessel to the bottom of the CCZ to see how mining will affect the strange, little-known animals that live where light does not reach.
“We were trying to measure the rate of oxygen consumption at the seafloor,” lead study author Andrew Sweetman from the Scottish Association for Marine Science (SAMS) told AFP.
To do this, they used a device called a sediment chamber to scrape up large amounts of sediment.
Normally, the amount of oxygen trapped in the chamber “decreases as the organisms breathe and are consumed,” Sweetman said.
But this time, the opposite happened: the amount of oxygen increased, which is something that can’t happen in complete darkness, where photosynthesis cannot take place.
This was so shocking that the researchers initially thought that their underwater sensors must have malfunctioned, so they brought some chunks aboard the ship and repeated the tests, and the oxygen levels increased again.
They then noticed that the nodes carried a surprising electrical charge.
“To our surprise, we found that the surface of the nodules has a voltage roughly equivalent to that of a AA battery,” Sweetman said. This charge could cause seawater to split into hydrogen and oxygen in a process called seawater electrolysis, the researchers said.
This chemical reaction occurs at 1.5 volts, roughly the same charge as an AA battery.
SAMS director Nicholas Owens said it was “one of the most exciting discoveries in marine science in recent years”.
The discovery that oxygen can be produced outside of photosynthesis “demands a rethinking of how the evolution of complex life on Earth began,” he said.
“The conventional view is that oxygen was first produced about 3 billion years ago by ancient microorganisms called cyanobacteria, and that complex life gradually developed thereafter,” Owens said.
Sweetman said the team’s findings show that “life could have begun somewhere other than on land.”
“And if this process is happening on Earth, could it be creating oxygen-rich habitats on other ocean planets, like Enceladus and Europa, providing opportunities for life?” he said.
the study, Published in Nature ScienceThe project is being partially funded by Canadian Metals Company, which aims to begin mining deposits in the CCZ next year.
