Dark oxygen at the depths of the Pacific Ocean might prompt a rethink about the beginnings of life.
In the utter darkness of the Pacific Ocean’s depths, scientists discovered that oxygen is created not by living things but by weird potato-shaped metallic lumps that emit nearly as much power as AA batteries.
The surprising discovery has several possible consequences, including revisiting how life initially originated on Earth, according to the study’s authors on Monday.
It was considered that only living organisms, such as plants and algae, could produce oxygen through photosynthesis, which needed sunshine.
However, four kilometers (2.5 miles) below the surface of the Pacific Ocean, where no sunlight can penetrate, microscopic mineral formations termed polymetallic nodules have been documented producing so-called dark oxygen for the first time.
The finding was found in the Clarion-Clipperton Zone (CCZ), an abyssal plain spanning Hawaii and Mexico, where mining companies intend to begin collecting the nodules.
The lumpy nodules, sometimes known as “batteries in a rock,” are rich in metals including cobalt, nickel, copper, and manganese, all of which are used in batteries, cellphones, wind turbines, and solar panels.
A worldwide team of scientists dispatched a tiny vessel to the floor of the CCZ to investigate how mining may effect the unique and little-known organisms that live where no light can reach.
“We were trying to measure the rate of oxygen consumption by the seafloor,” main research author Andrew Sweetman from the Scottish Association for Marine Science (SAMS) told AFP.
To do this, they employed a device known as a benthic chamber, which scooped up a large amount of silt.
Sweetman explained that the amount of oxygen contained in the chamber often “decreases as it is used up by organisms as they respire.”
But this time, the reverse occurred: the amount of oxygen rose. This was not expected to happen in full darkness, as there is no photosynthesis.
This was so stunning that the researchers assumed their underwater sensors had malfunctioned. So they took up several nodules on their ship and repeated the test. Again, the amount of oxygen rose.
An aerial picture of a diamond mining ship with a helipad at sea.
They subsequently observed that the nodules carried a surprising electric charge.
Sweetman stated that the scientists “amazingly found voltages almost as high as are in an AA battery” on the nodule’s surface. The researchers suggested that this charge may divide saltwater into hydrogen and oxygen through a process known as seawater electrolysis.
This chemical reaction takes place at around 1.5 volts, which is roughly the charge of an AA battery.
The SAMS director, Nicholas Owens, described it as “one of the most exciting findings in ocean science in recent times.”.
The finding of oxygen created outside of photosynthesis “requires us to reconsider how the evolution of complex life on the planet may have begun,” he added.
“The conventional view is that oxygen was first produced around 3 billion years ago by ancient microbes called cyanobacteria, and there was a gradual development of complex life thereafter,” Mr. Owens added.
Sweetman stated that the team’s discovery demonstrated that “life could have started elsewhere than on land.”.
And, if the process is taking place on our planet, might it be helping to create oxygenated environments on other ocean worlds like Enceladus and Europa, allowing life to exist?” he said.
The study, published in the journal Nature Geoscience, was partially sponsored by Canada’s The Metals Company, which plans to begin mining the nodules in the CCZ next year.
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