Pollen From Permian/Triassic Extinction Show UV Induced Mutations

[Richard W Travsky <rtravsky@uwyo.edu>]

http://dsc.discovery.com/news/afp/20031013/pollen.html

Oct. 17, 2003  Conifer tree pollen from 250 million years ago show the
same mutations as those of modern pines hit by fallout from the Chernobyl
nuclear power plant disaster, a new study has found.

The prehistoric mutations probably occurred after gas and dust from
massive volcanic eruptions damaged Earth's ozone layer, resulting in a
torrent of damaging ultra-violet radiation from the sun, according to
Clinton Foster, of Geoscience Australia, who presented the findings at a
recent conference at Utrecht, Netherlands.

"An extreme change in the environment resulted and that caused conifers to
produce mutant pollen," Foster told ABC Science Online. "The fascinating
thing is that modern conifers show just these sorts of mutations in
response to stress, such as extreme cold, dryness, or the Chernobyl
fallout." 

The pollen dates from about the time of the Permian-Triassic mass
extinction event, which killed off more than 90 percent of the world's
animals, but evidence of its impact on living things has been largely from
marine environments: the new discovery is among the first to reveal how a
major group of land plants reacted, Foster said.

Working with Sergey Afonin, of the Paleontological Institute, Moscow, and
Professor Xiaofeng Wang, of the Center for Stratigraphy & Palaeontology,
Yichang, Foster found the mutant pollen trapped in ancient lake-bed
sediments at sites as far apart as Urumqi, almost 1,400 miles west of
Beijing in China, and Nedubrovo, about 500 miles north-east of Moscow.

"About 250 million years ago the world was an alien place, with what is
now Russia and China separated by thousands of kilometers and an immense
ocean," Foster said. "The only thing that linked the two land masses was
the atmosphere.

"Sudden and drastic changes in the atmosphere, such as those caused by
massive volcanic eruptions, would have released huge amounts of dust and
gases into the air. The ozone layer would have been damaged and there
would have been a subsequent increase in ultra-violet B light." 
...
With the collaboration of Professor Ian Metcalfe of the University of New
England in Australia, the team studied thousands of fossil pollen grains
trapped in the Permian-Triassic rocks and discovered that they showed the
same mutations in the sack structures as stressed modern conifer species
do.
...
He predicts that similar evidence of mutant pollens and spores will be
found in sediments laid down at the time of other mass-extinction events,
such as the one that wiped out the dinosaurs about 65 million years ago.