Commercial fishermen and other mariners form the words 'Acid Ocean' during an event held to spread the message of saving the oceans from acidification caused by fossil fuel emissions, in Homer, Alaska, in this file photo taken on 6 September 2009. Photo: Lou Dematteis / Reuters

By Will Dunham; Editing by Mohammad Zargham
9 April 2015

WASHINGTON (Reuters) – It is one of science's enduring mysteries: what caused the worst mass extinction in Earth's history. And, no, it is not the one that wiped out the dinosaurs.

Scientists said on Thursday that huge amounts of carbon dioxide spewed from colossal volcanic eruptions in Siberia may have turned the world's oceans dangerously acidic 252 million years ago, helping to drive a global environmental calamity that killed most land and sea creatures.

The researchers studied rocks in the United Arab Emirates that were on the seafloor at the time and contained a detailed record of the changing ocean conditions at the end of the Permian Period.

"This is one of the few cases where we have been able to show that an ocean acidification event happened in deep time," said University of Edinburgh geoscientist Rachel Wood, one of the researchers in the study published in the journal Science.

"This is significant because we believe our modern oceans are becoming similarly acidic," Wood added. "These findings may help us understand the threat posed to marine life by modern-day ocean acidification."

Various hypotheses have been offered to explain the mass extinction that exceeded even the one 65 million years ago caused by an asteroid impact that erased the dinosaurs and many other animals. The researchers said ocean acidification had long been suspected but no direct evidence had been found until now.

Massive eruptions that formed an immense region of volcanic rock called the Siberian Traps represented one of the largest volcanic events of the past half billion years, lasting a million years and spanning the boundary between the Permian and subsequent Triassic Period.

The prodigious amounts of carbon dioxide from the eruptions had awful consequences for land and marine life. The absorption of carbon dioxide lethally, but temporarily, changed the chemical composition of the oceans, the researchers said.

The mass extinction unfolded over a period of 60,000 years, they said. [more]

Acidic oceans implicated in Earth's worst mass extinction


  1. Anonymous said...

    This article takes on a summatively important topic but does not provide enough information. On finishing, I did not capture any sense of the related research and other contextualizing information pertinent to understanding why the topic, in this particular instance, is important (or why historical context might render it less important). A research link to original sources, pdf report etc would be helpful. We now have found the missing fig in the pudding (acidification at the same time as major extinction event), Im not sure you could have a more important finding. But what do we do with it? Who found it? How can I take specific information from this to follow up on the topic?  


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