Study says ocean acidification led to mass extinction

Ocean acidification triggered by massive volcanic eruptions helped cause the worst mass extinction in the history of life on Earth, according to a new study.

The findings, published in the journal Science, shed light on the dangers of rising ocean acidity – a phenomenon that is contributing to the deaths of coral and other marine life today.

If you thought the worst extinction event on the planet was the one that killed the dinosaurs some 66 million years ago, think again. A far worse event, the Permo-Triassic Boundary mass extinction event, happened some 252 million years ago, and over the course of about 60,000 years is thought to have wiped out more than two-thirds of land species and more than 90 percent of marine species on Earth.

Scientists have debated exactly what caused this devastating die-off. Now, in a new paper, a team led out of the University of Edinburgh has found that there were two major phases to this extinction that acted as a one-two punch to wipe out most living things.

“The first phase of extinction was coincident with a slow injection of carbon into the atmosphere, and ocean pH remained stable,” the authors wrote. “During the second extinction pulse, however, a rapid and large injection of carbon caused an abrupt acidification event that drove the preferential loss of heavily calcified marine biota.”

This double whammy proved too much for life on Earth – particularly for the animals, such as oysters or coral, that need to pull minerals out of the ocean to build their shells and skeletons. Acidification reduces the amount of available calcium carbonate.

Carbon is being injected into the atmosphere today at a similar rate. A high rate of carbon injection, not just the overall amount, was probably a major part of the problem because it left species with little time to adapt.