Where Life Found Refuge During Mass Extinction

Oct. 3, 2008 -- During the worst apocalypse the planet has ever known, somehow, life found a way to survive. But how? Scientists now think they have an answer: a nurturing refuge in the shallow continental shelf waters of northwestern Pangea.

During the end of the Permian era 250 million years ago, global warming ran rampant on Earth, extinguishing 95 percent of life in the ocean, and 70 percent of life on land.

Through the darkest days, the planet was a barren wasteland. Ocean circulation, so vital to our modern climate, had shut off. Huge algal blooms sucked the seas dry of oxygen. Poisonous hydrogen sulfide built up to lethal concentrations in the water and may have even been belched into the atmosphere, suffocating organisms on shore.

The fossil record of the Permian-Triassic extinction is a stark one -- rocks go from teeming with life to nearly empty in the geologic blink of an eye. But searching through deposits left at the height of the extinction event, Tyler Beatty of the University of Calgary discovered something nobody ever expected to see: an almost fully-intact marine ecosystem.

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Amid the barren, empty sedimentary rocks Beatty found tracks left by hard-shelled arthropods, teeth from small fish, and the burrows of ancient crustaceans that would rival their modern descendants, lobsters, in size.

"We see as many as 23 different genera of animals in some of these rocks. You'd be lucky to see that if you went out and scooped up a piece of the ocean floor today," Beatty said.