Earth experienced its biggest mass extinction 250 million years ago. New evidence from Stanford, which looks at calcium isotopes, suggests massive volcanic eruptions were to blame for ocean acidification that wiped out 90 percent of marine biodiversity. The result may parallel today’s climate change and ocean acidification.
New evidence gleaned by analyzing calcium embedded in Chinese limestone suggests that volcanoes, which spewed massive amounts of carbon dioxide into the atmosphere for a million years, caused the biggest mass extinction on Earth.
In a paper published April 26 in the Proceedings of the National Academy of Sciences, a team of researchers led by a Stanford geologist said that as carbon dioxide gas dissolved in the oceans, it raised the acidity of seawater.
The research team said it was a deadly combination – carbon dioxide in the atmosphere and higher acidity in the oceans – that eventually wiped out 90 percent of marine species and about three-quarters of land species, in a cataclysmic event 250 million years ago known as the “end-Permian extinction.”
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Gwyneth Dickey, Stanford University News, 27 April 2010. Full press release.
