Re: Pollen From Permian/Triassic Extinction Show UV Induced Mutations

["David Marjanovic" <david.marjanovic@gmx.at>]

----- Original Message -----
From: "Nick Pharris" <npharris@umich.edu>

> > "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."
>
> OK, so the mutations do not necessarily indicate the presence of
DNA-damaging
> radiation, thus mooting Foster's whole argument about the ozone layer.  Or
did
> I miss something?

It is interesting that an impact the size of Chicxulub must generate a few
months of noticeable cold, _as well as_ enough nitrogen oxides to make the
ozone layer disappear very, very fast.

I cannot imagine aridity being involved in a mass extinction. Global
synchronous aridity would be needed for that -- and why should that happen?

The regression was AFAIK quite slow, as usual.