Last Gasp: Toxic gas could explain great extinction | Science News

SUPPORT SCIENCE NEWS

Help us keep you informed.

Real Science. Real News.


News

Last Gasp: Toxic gas could explain great extinction

By
9:53am, May 25, 2005

Poisonous gas bubbling up from the deep ocean could have caused the largest extinction of species in Earth's history. A new model describes how hydrogen sulfide gas produced by marine microbes might suddenly have built up in the atmosphere 250 million years ago, poisoning land animals. The same event would have destroyed the planet's protective ozone shield and thus killed many land and marine plants.

Researchers have debated the cause of that ecological disaster, which extinguished 95 percent of marine and 70 percent of land species at the end of the Permian period. Scientists have proposed as possible culprits meteor impacts (SN: 11/22/03, p. 323: Pieces of a Pulverizer? Sediment fragments may be from killer space rock), global warming from major volcanic eruptions, and changes in ocean chemistry (SN: 2/1/97, p. 74). In the May Geology, Lee Kump of Pennsylvania State University in State College and his colleagues argue that ocean venting of

This article is only available to Science News subscribers. Already a subscriber? Log in now. Or subscribe today for full access.

Get Science News headlines by e-mail.

More from Science News

From the Nature Index Paid Content