White quartz veins in granite off the northeast coast of the USA
Richard Berube / Alamy Inventory {Photograph}
Earthquakes and different geological processes could have activated oxygen-producing reactions that formed the evolution of a few of Earth’s oldest organisms.
Immediately, oxygen makes up about one-fifth of Earth’s ambiance, and most of it’s produced by crops and microbes. It did not begin that means. There was little or no oxygen within the ambiance till ranges rose throughout the Nice Oxidation Occasion 2.4 billion to 2.3 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 all through the tree of life suggests some publicity to oxygen to a standard ancestor that existed earlier than the Nice Oxidation Occasion.
Mark Thiemens On the College of California, San Diego, and his colleagues grinded quartz rock and uncovered it to water beneath chemical circumstances much like these on Earth earlier than excessive oxygen ranges. Researchers used quartz as a result of it’s the easiest and commonest silicate mineral.
They discovered that damaged crystals on the floor of quartz can react with water to type molecular oxygen and different reactive oxygen species reminiscent of hydrogen peroxide. These molecules, also referred to as free radicals, would have been vital to early evolution, he says, as they will harm DNA and different elements of cells. Timothy Lyons On the College of California, Riverside, not concerned.
“Life was capable of develop the enzymatic skills of those species very early to cope with their detrimental results,” he says.
In nature, quartz and different silicate minerals can equally be eroded by earthquakes, erosion, or transferring ice. They will then work together with water to provide the identical oxygen molecules. Researchers estimate that seismic processes alone might produce 100 billion instances extra hydrogen peroxide than atmospheric reactions, one other doable supply of abiotic oxygen.
Lyons says variations to this seismic oxygen provide might assist some organisms survive the unconventional shift in Earth chemistry that accompanied the Nice Oxidation Occasion a whole lot of hundreds of thousands of years later.
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 produce oxygen, which could possibly be an essential issue for detecting life on these worlds.
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