Volcanic eruptions wiped out ocean life

- It certainly caused an extinction of several species in the marine environment. It wasn't as big as what killed off the dinosaurs, but it was what we call an extreme event in the Earth's history, something that doesn't happen very often, said University of Alberta Earth and Atmospheric Science researcher Steven Turgeon.

According to their research, the eruptions preceded the mass extinction by a geological blink of the eye. The event occurred within 23.000 years of the extinction and the underwater volcanic eruption had two consequences: first, nutrients were released, which allowed mass feeding and growth of plants and animals. When these organisms died, their decomposition and fall towards the sea floor caused further oxygen depletion, thereby compounding the effects of the volcanic eruption and release of clouds of carbon dioxide in to the oceans and atmosphere. The result was a global oceanic anoxic event, where the ocean is completely depleted of oxygen.

- After 10,000-50,000 years, the carbon dioxide levels rose again. "Business as usual," said Turgeon, adding that this might hold a warning for organic life on the planet today, he said.

another study, same predictions
This is however not the first study which blames volcanic eruptions for mass extinction of life on earth. According to a study published in 2004, suggests that volcanic activety wiped out 90 percent of marine life at the end of the Permian period, 248 million years ago.

Christian Koeberl of the University of Vienna and an international team of scientists studied rock samples from the Dolomites and the Carnic Alps of Italy and Austria. They found that the elements and compounds deposited in these late-Permian rocks were more similar to Earth rocks than to extraterrestrial rocks.

The scientists did find evidence of high levels of carbon dioxide, likely caused by volcanic activity. Near the end of the Permian period, tension in the Earth’s crust in present day Siberia led to massive volcanic activity in the region.

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