Discovery in the deep sea – MASHAHER

In the pitch-dark wilderness of the deep sea, which hosts a trove of translucent creatures and billions of tonnes of critical metals, something extraordinary is happening: oxygen is spawning in the absence of light.

That’s the conclusion of scientists who have reported nodules of metallic rock on the sea floor are generating their own voltage and splitting water into hydrogen and so-called “dark oxygen”.

The finding could impact the plans of mining companies to harvest these metal-rich nodules, and the discovery also challenges theories about how life arose on Earth and where it might exist on other planets.

“Our understanding has been that Earth’s oxygen supply began with photosynthetic organisms,” lead author of the Nature Geoscience research, Professor Andrew Sweetman, said. “But we now know that there is oxygen produced in the deep sea, where there is no light. I think we therefore need to revisit questions like: where could aerobic life have begun?”

Vast abyssal plains on the ocean floor are dotted with these dark potato-like lumps, called polymetallic nodules, which hold trillions of dollars worth of cobalt, nickel, manganese and other metals critical for lithium-ion batteries and electric vehicles.

Sweetman and his colleagues have been studying the Clarion-Clipperton Zone, an area of the Pacific Ocean between Hawaii and Mexico slated for deep-sea mining. They lowered chambers over nodules more the 4000 metres deep. Instead of oxygen decreasing in the chambers, as expected, over two days the levels steadily grew.

The scientists cross-checked their readings, ruled out faulty equipment and tested multiple sites. Oxygen levels kept increasing.

That’s when Sweetman knew they were on to something “groundbreaking and unthought of”.