2024-07-30 06:00:15
Metallic pebbles, nodules the size of potatoes, dot the floor of the Pacific Ocean. But what’s surprising is their ability to produce oxygen in total darkness, without the help of any living organisms, according to a new study. research.
Credit: DeepCCZ expedition
The discovery of oxygen produced without biological intervention, called “dark oxygen”, has revolutionized our knowledge of the emergence of life on Earth. Researchers thought it was a failure of the sensors, used to observing oxygen consumption in the depths.
Andrew Sweetman, the study’s leader and a professor at the Scottish Association for Marine Science (SAMS), said their instruments consistently showed oxygen production. The results, published in Nature Geoscienceindicate that these North Pacific nodules produce oxygen by electrolysis of the’sea waterdue to a electric potential between metal ions.
The abyssal plains, located between 3000 and 6000 meters deep, are full of these nodules composed mainly of iron and manganese oxides, but also of cobalt, nickel, lithium and rare earth as the waxessential to electronic and low-footprint technologies carbone.
Sweetman and his team initially studied the potential impact of mining these nodules in the Clarion-Clipperton Zone (CCZ), which stretches 4.5 million square kilometers from Hawaii to Mexico. Oxygen measurements made with experimental chambers revealed consistent emissions from the seafloor, contradicting the expectation that oxygen would decrease with depth.
Polymetallic nodules are aggregates composed of iron and manganese oxides, also containing precious metals such as cobalt and rare earths.
Crédit: NOAA Office of Ocean Exploration and Research, 2019 Southeastern U.S. Deep-sea Exploration
This discovery challenges the idea that Earth’s oxygen comes solely from photosynthesis, and raises new questions about the origin of life, about 3.7 billion years ago. If life has need oxygen to begin with, this abyssal production offers a new perspective on the possible places where life emerged aerobic.
Finally, this revelation raises concerns about the mining of polymetallic nodules. These “natural batteries” could be essential to the deep-sea ecosystem, and their extraction could have significant ecological consequences.
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