Oxygen on early Earth might 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 now, oxygen makes up round a fifth of Earth’s environment, with most of it produced by vegetation and microbes. It didn’t begin that manner. There was little or no oxygen within the environment till ranges spiked through the Nice Oxidation Occasion between 2.4 billion and a pair of.3 billion years in the past due to the speedy unfold of microbes that launch oxygen by photosynthesis.

Nevertheless, the widespread presence of antioxidant enzymes throughout the tree of life suggests a standard 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 beneath chemical circumstances just like these on Earth previous to excessive ranges of oxygen. The researchers used quartz as a result of it’s the easiest and commonest 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, reminiscent of hydrogen peroxide. Often known as free radicals, these molecules would have been crucial to early evolution as a result of they’ll harm DNA and different elements of cells, says Timothy Lyons on the College of California, Riverside, who wasn’t concerned with the work.

“Life was able to develop very early the enzymatic capabilities of dealing with the harmful effects of these species,” he says.

In nature, quartz and different silicate minerals may very well be equally abraded by earthquakes, erosion or transferring 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 occasions 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 tons of of hundreds of thousands of years later, says Lyons.

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