Ocean of acid blamed for Earth’s ‘great dying’

Posted by Jeff on Apr 13, 2015 @ 9:34 am in Conservation | 0 comments | Last modified: April 13, 2015

Death by acid was the fate of the sea monsters that perished in Earth’s biggest mass extinction, some 251 million years ago, a new study finds.

Nearly every form of ocean life disappeared during this “Great Dying” at the end of the Permian period, when more than 90 percent of all marine species vanished, from the scorpionlike predators called eurypterids to various types of trilobites, some with alienlike stalked eyes. It’s the closest Earth has ever come to completely losing its fish, snails, sea plankton and other marine creatures. Some 70 percent of animals and plants on land died off at the same time.

Now, there is direct evidence that ocean acidification dealt the final blow to species already suffering from these huge environmental changes. By analyzing boron embedded in limestone from the Permian and Triassic periods, researchers discovered an abrupt shift in ocean pH levels. The change in acidity corresponds to a drop in surface ocean pH levels of 0.6 to 0.7 pH units that lasted about 10,000 years. In comparison, modern ocean pH levels have fallen by 0.1 pH units since the Industrial Revolution, a 30 percent increase in acidity.

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