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(CNN) - The most catastrophic destruction on Earth did not happen to dinosaurs.
A new study found that extreme changes in the atmosphere killed almost 100% of life on Earth about 2 billion years ago.
Researchers took samples of barite, a mineral over 2,000 million years old, in the subarctic belntaric islands of Canada. Rocks that have etched "chemical signatures," useful clues for researchers to discover what the atmosphere was like when the rocks formed, he told CNN Malcolm Hodgskiss, lead co-author and Ph.D. candidate. from Stanford University.
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Yes there is such a thing as a lot of oxygen
The study focused on a phenomenon called the "Great Oxidation Event". It is like this: billions of years ago, only microorganisms survived on Earth. When they photosynthesized, they altered the chemical composition of the atmosphere, creating an excess of oxygen that they finally could not maintain.
The microorganisms depleted the nutrients they needed to create oxygen, which left the Earth's atmosphere unbalanced. This led to a "huge fall" in the biosphere: the amount of life on Earth. The scientists were not sure how drastic the fall was so far.
The team's calculations showed that between 80 and 99.5% of the organisms were eliminated at the end of the Great Oxidation Event, Hodgskiss said. There were simply too many and they produced too much oxygen.
"Even our most conservative estimates would exceed estimates of the amount of life that died during the extinction of dinosaurs approximately 65 million years ago," said Hodgskiss.
Ancient revelations that are relevant today
How did researchers study what the world was like before humans lived in it?
They combined a model of the amount of carbon dioxide and oxygen that could be in the atmosphere and then relied on previous research with their chemical measurements of barite to calculate how much life there was at that time.
The findings are older than most life on Earth, but today they are relevant to the planet because the Earth is still vulnerable to atmospheric changes, Hodgskiss said. The oceans are warming, which affects the amount of nutrients they contain. Ocean discharges also alter underwater ecosystems, threatening photosynthetic organisms that contribute more than half of the oxygen in Earth's atmosphere.
Danger of extinction