Discover: UC professor explains 'slow doom that swept planet'

Scientists are still puzzling over one of the the Earth's biggest mass extinction 380 million years ago during the Devonian that killed three-quarteres of species on Earth.

University of Cincinnati geologist Thomas Algeo shared his theory for this mass extinction with Discover Magazine. Scientists don't think it was a meteor or comet like the one believed to have killed off the dinosaurs 65 million years ago.

But Algeo, a professor of geology in UC's College of Arts and Sciences, said a surprising culprit might have spelled the Earth's doom. According to Algeo, the proliferation of vascular plants across the Earth released massive nutrients and minerals that fueled toxic algae blooms that robbed the oceans of oxygen.

“There’s been a lot of searching for a plausible candidate,” Algeo told Discover.

Algeo and his research collaborators published their theory in 1995 in the Geological Society of America.

Read the Discover story.

Featured illustration at top: A predatory gorgonopsid surveys a volcanic eruption that spells its doom during one of the Earth's five biggest mass extinctions. Illustration/Margaret Weiner/UC Creative + Brand