Marks of Extinction
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By Karla Harby

During the late Permian period—roughly 260 million years ago—at least 90 percent of Earth's species vanished, never to be seen again. Researchers use Alliance resources to explore why.

The single largest mass extinction of species that our planet has ever seen occurred not with the end of the Age of Dinosaurs, some 65 million years ago. Rather it occurred much earlier—toward the end of the Permian period, which spanned 286 to 245 million years ago and immediately preceded the beginning of the Age of the Dinosaurs. In the late Permian, most species, including perhaps 95 percent of all life in the oceans, simply ceased to be.

Explanations for this mass extinction have been debated since it was discovered in the 1820s. In this respect, researching the Permian is much like researching the late Cretaceous, when the dinosaurs disappeared. But there's one big difference: 260 million years ago is a lot further away than a mere 65 million years. This dramatically affects the amount and kinds of evidence available to scientists studying the Permian mass extinction.

"One of the interesting things about this is that the number of data points is very, very small," says John Marshall, an atmospheric scientist at the Massachusetts Institute of Technology. "Speculations are made from a few dozen data points, so there isn't much data to constrain the speculations."

That's where Alliance resources come in. Using the Alliance SGI Origin2000 supercomputer at Boston University, Marshall and colleagues—including MIT biogeochemist Mick Follows and graduate student Rong Zhang—are building complex models of the Permian environment. While not full-blown simulations of the Permian world—there are simply too few data for that—these models allow the scientists to explore the feasibility of various extinction scenarios. That's because the models draw not only on the sparse geological record of the Permian, but also on oceanography, atmospheric science, paleobiology, and relevant chemistries.

Access Online | Posted 4-23-2002

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