You might have heard previous reports on studies showing how rising levels of atmospheric carbon dioxide have been causing ocean acidification, making it harder for sea life to build their vital calcium shells or skeletons, and how oxygen dead marine zones are increasing. Well, the earth’s been there and done that, apparently about a quarter of a billion years ago, generating the largest extinction of life ever on Earth, reports Alanna Mitchell at the New York Times. In a recently published study in the journal Geology, Stanford and University of California scientists examined the fossil cells of nearly 50,000 sea creatures. They concluded that the animals died from a lack of dissolved oxygen, an excess of carbon dioxide, a reduced ability to make calcium-based shells, altered ocean acidity and higher water temperatures. Likely caused by extreme volcanism that exploded atmospheric levels of carbon dioxide, the stresses happened rapidly and each one amplified the effects of the others. All these conditions are now developing in our oceans. The only difference is, we’re increasing atmospheric carbon dioxide far faster than those ancient volcanoes ever did.
the abstract of the study is at: http://geology.gsapubs.org/content/39/11/1059.abstract