Plankton confirms dinosaurs' demise theory

[Tim Williams <twilliams_alpha@hotmail.com>]

Plankton confirms dinosaurs' demise theory

http://www.smh.com.au/articles/2004/06/24/1088046225554.html

Washington: Fossil plankton dating from 65 million years ago helps confirm 
the theory that a dark winter lasting many thousands of years doomed the 
dinosaurs, researchers say.

Many experts believe that an asteroid struck the Earth then and kicked up 
dust that obscured the sun, and that the impact also set off volcanic 
eruptions that disrupted the climate for centuries.

These changes forced many species into extinction, including the dinosaurs. 
The ancestors of today's mammals survived to later emerge and fill the empty 
niches left by their former rivals and predators.

Evidence of a giant crater dating back to about the right time has been 
found in what is now Mexico's Yucatan Peninsula area.

Writing in the journal Geology, a team of scientists, led by Simone Galeotti 
of the University of Urbino in Italy and Henk Brinkhuis of the University of 
Utrecht in the Netherlands, said a Tunisian site called El Kef had now 
yielded evidence of the sudden cooling that would have followed.

The evidence comes in the form of small, cold-loving ocean organisms called 
dinoflagellates and benthic formanifera. They seem to have appeared suddenly 
in an ancient sea that had previously been very warm, said Matthew Huber of 
Purdue University, Indiana, who worked on the study.

Professor Huber said the findings could also help experts understand today's 
climate changes.

"This discovery, which certainly has relevance to theories about dinosaur 
extinction, is also significant because it confirms our computer models of 
the Earth's climate - they predict that the climate would respond in this 
way under the circumstances."

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