A team of researchers discovered a new source of oxygen at the bottom of the ocean, and it's discovery has led to more questions being asked than answered.
The discovery was detailed in a new paper published in the scientific journal Nature Geoscience, which explains the new oxygen source is called "dark oxygen," which is likely a reference to dark matter in astronomy as it can be measured but not seen. Much like dark matter, researchers first discovered dark oxygen when they discovered oxygen levels at the seafloor were rising, which would be impossible at depths of 13,000 feet, particularly without any photosynthetic processes.
"When we first got this data, we thought the sensors were faulty because every study ever done in the deep sea has only seen oxygen being consumed rather than produced. We would come home and recalibrate the sensors but over the course of 10 years, these strange oxygen readings kept showing up," said Biogeochemist Andrew Sweetman from the Scottish Association for Marine Science (SAMS)
The team investigated the strange oxygen readings further by collecting some of the nodule rocks from the seafloor. These rocks are comprised of rare Earth minerals such as cobalt, manganese, and nickel, but are jumbled up in one stone. Notably, cobalt is extremely valuable for rechargeable batteries, which is, funnily enough, how oxygen is being produced at the bottom of the ocean.
The team discovered that each of these rocks is capable of producing voltages of up to 0.95V, which means that when hundreds, thousands, or even millions of these electricity-producing rocks are connected together, they can achieve the 1.5 V required to split oxygen from water in an electrolysis reaction.
"It appears that we discovered a natural 'geobattery,'" says Northwestern University chemist Franz Geiger. "These geobatteries are the basis for a possible explanation of the ocean's dark oxygen production."
"We now know that there is oxygen produced in the deep sea, where there is no light," says Sweetman. "I think we, therefore, need to revisit questions like: Where could aerobic life have begun?"
"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," says SAMS marine scientist Nicholas Owens