Oxygen on early Earth may have come from quartz crushed by earthquakes

Earthquakes and different geological processes might have enabled oxygen-producing reactions that formed the evolution of a few of Earth’s earliest organisms.

Right this moment, oxygen makes up round a fifth of Earth’s ambiance, with most of it produced by crops and microbes. It didn’t begin that method. There was little or no oxygen within the ambiance till ranges spiked throughout the Great Oxidation Event between 2.4 billion and a pair of.3 billion years in the past because of the fast unfold of microbes that launch oxygen by means of photosynthesis.

Nevertheless, the widespread presence of antioxidant enzymes across the tree of life suggests a typical ancestor that existed previous to the Nice Oxidation Occasion was uncovered to some quantity of oxygen.

Mark Thiemens on the College of California, San Diego, and his colleagues floor up quartz rock and uncovered it to water underneath chemical circumstances much like these on Earth previous to excessive ranges of oxygen. The researchers used quartz as a result of it’s the easiest and most typical silicate mineral.

They discovered that the damaged crystals on the floor of quartz can react with water to kind molecular oxygen and different reactive oxygen species, equivalent to hydrogen peroxide. Also called free radicals, these molecules would have been important to early evolution as a result of they will damage DNA and different parts of cells, says Timothy Lyons on the College of California, Riverside, who wasn’t concerned with the work.

“Life was in a position to develop very early the enzymatic capabilities of coping with the dangerous results of those species,” he says.

In nature, quartz and different silicate minerals might be equally abraded by earthquakes, erosion or shifting ice. They might then work together with water to provide those self same oxygen molecules. The researchers estimated that seismic processes alone may have generated 100 billion instances extra hydrogen peroxide than atmospheric reactions, one other doable supply of abiotic oxygen.

Diversifications to this seismic supply of oxygen might have helped some organisms survive the unconventional shift in Earth’s chemistry that accompanied the Nice Oxidation Occasion a whole bunch of thousands and thousands of years later, says Lyons.

The researchers add that related geological processes on different planetary our bodies, equivalent to sandstorms on Mars or tidal fluctuations on Saturn’s moon Enceladus, may additionally produce oxygen, which might be an vital issue for detecting life on these worlds.