Scientists have discovered that mineral-rich sediments at the bottom of the Pacific Ocean produce oxygen through chemical reactions with water molecules. The gas may have originated in the same way at the bottom of Earth's primordial ocean.
“The emergence of aerobic life on Earth required sources of oxygen, which is traditionally produced by photosynthetic organisms, but now it turns out that its molecules also originate in the deep ocean, where there is no light,” says Professor Andrew Sweatman, of the Scottish Society for Oceanography. “So we are rethinking where and when the first aerobic inhabitants of Earth lived.”
Scientists made the discovery while studying rock samples collected from the bottom of the Pacific Ocean in an area called the Clarion-Clipperton Ridge, a wide strip of land in the Pacific Ocean between Clarion and Clipperton Islands. At the bottom of the Ridge are many spherical mineral masses, 3-10 cm in diameter, containing iron, lithium, manganese and other minerals.
“When we first got these results, we thought our equipment was broken because at this depth, oxygen is always being consumed rather than produced,” says the professor. “So we have organised several expeditions over the past 10 years and the results were similar even when we used other methods, which confirms this surprising discovery.”
Studying these mineral cocci in the laboratory has shown that they do indeed produce oxygen because these minerals are natural batteries that generate electricity when they come into contact with seawater. The movement of current through the water causes the water to decompose and oxygen to accumulate in the ocean layers located next to these cocci. According to scientists, the reserves of this gas play an important role in the lives of microbes and other organisms that live on the bottom of the Pacific Ocean.