"Explosive Microbial Growth Caused Earth's Greatest Extinction Event" --The Great Dying (Today's Most Popular)15 Jul 2014, 14:54 UTC
The physical environment can produce sudden shocks to the life of our planet through impacting space rocks, erupting volcanoes and other events. But sometimes life itself turns the tables and strikes a swift blow back to the environment. MIT researchers have identified a different culprit — one coming from biology rather than geology. They argue that the carbon disruption and, consequently, the end-Permian extinction were set off by a particular microorganism that evolved a new way to digest organic material into methane.
The end-Permian (or PT) extinction event occurred 252 million years ago. It is often called the Great Dying because around 90 percent of marine species disappeared in one fell swoop. Similar numbers died on land as well, producing a stark contrast between Permian rock layers beneath (or before) the extinction and the Triassic layers above. Extinctions are common throughout time, but for this one, the fossil record truly skipped a beat.
"The end-Permian is the greatest extinction event that we know of," said Daniel Rothman, a geophysicist at the Massachusetts Institute of Technology. "The changes in the fossil record were obvious even to 19th Century geologists."
Understanding the cause of this biological devastation requires understanding the geochemical clues ...