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Updated 11:29 AM EDT, Tue, Jun 16, 2020

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Ocean Acidification to Blame for the Earth's Worst Mass Extinction

The dangerous oceans

(Photo : NOAA) Ocean acidification illustrated

New research suggests ocean acidification and volcanic activity caused the "Great Dying" at the end of the Permian period some 252 million years ago, the most devastating mass extinction event in history.

Ocean acidification is also related to global warming. It results, like climate change, from human emissions of greenhouse gases that are absorbed into the sea, lowering the water's pH level.

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The oceans have already become 30 percent more acidic over the past 200 years, resulting in the devastating extinction of 90 percent of marine species and over two-thirds of the animals present on land, the University of Edinburgh reported

The Great Dying or the Great Permian Extinction occurred when the Earth's oceans absorbed massive amounts of carbon dioxide emitted by volcanic eruptions. It caused up to 96 percent of all marine species and 70 percent of terrestrial vertebrate species to become extinct.

The massive absorption changed the ocean's chemistry, causing it to become more acidic. This acidification was believed to be what pushed this extinction event over the edge, causing the massive loss of diversity.

"Scientists have long suspected that an ocean acidification event occurred during the greatest mass extinction of all time, but direct evidence has been lacking until now. This is a worrying finding, considering that we can already see an increase in ocean acidity today that is the result of human carbon emissions," said Matthew Clarkson of the University of Edinburgh's School of GeoSciences, who coordinated the study.

Researchers have analyzed rocks in the United Arab Emirates that were on the seafloor when the Great Dying occurred 252 million years ago, and which contains a record of prehistoric acidification.

The entire extinction period lasted 60,000 years, during which massive eruptions spewed carbon into the atmosphere and began to kill off terrestrial life. But in the last 10,000 years, so much carbon was released the oceans could no longer absorb it. The ocean began to rapidly acidify, putting additional pressures on the already weakened ecosystem that ultimately became too much for it to withstand.

The findings, published in the journal, Science, could help researchers gain insight into the threat posed by ocean acidification to modern sea life today.

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