Subject: Ozone hole starts taki (fwd)

Michael Williamson (
Sat, 15 Feb 1997 16:58:19 -0500 (EST)

---------- Forwarded message ----------
Date: Wed, 12 Feb 97 00:51:00 GMT 
Subject: FEATURE-Ozone hole starts taki

FEATURE-Ozone hole starts taking its toll in Antarctica

By Roger Atwood
     PALMER STATION, Antarctica (Reuter) - Starfish embryos
develop ugly deformities and die before they are born. Sea
urchins stop reproducing and some plants are producing their
own "sunscreen."
     Wildlife in Antarctica is starting to show the subtle but
unmistakeable effects of the ozone hole, the gap in the Earth's
atmosphere that lets the sun's ultraviolet rays bombard the
frozen continent for about four months every year.
     With plants and simple animals being damaged by the ozone
hole, can humans be far behind? That is a question scientists
would rather not answer yet, but at the simpler evolutionary
levels of life the effects are all around and seem to be growing
     Research by scientists at Palmer Station, a U.S. scientific
base on Anvers Island, shows high ultraviolet radiation damages
lower forms of life such as plankton and molluscs and could
start working its way up the food chain. No onedares guess at
the implications higher up the food chain, such as
plankton-eating whales and shellfish-eating seabirds.
     Biologists Isidro Bosch and Deneb Karentz have found that
embryos of limpets, starfish and other invertebrates do not
grow properly when hit by the springtime assault of ultraviolet
rays through the ozone hole. The embryos float by the millions
near the surface of the ocean, where they are easy prey for
predators -- and ultraviolet rays.
     "What we see is that they don't form in the normal pattern.
The entire structure is essentially deformed," said Karentz, of
the University of San Francisco. "If it's supposed to form in a
sphere, it forms in a sphere with a big lump."
    Adults do not seem to have the same problem because they have
protective shells and live at much greater depth, she said.

     Field and lab work by Karentz and Bosch show that high
ultraviolet-B (UVB) radiation damages the chromosones of the
animals, and "we can correlate the amount of damage to the
amount of UVB exposure," Karentz said.
     In other words, the more radiation, the more damage to the
animals' whole reproductive system.
     Scientists discovered the fraying of the stratosphere's
ozone layer in the 1970s and quickly tied it to the effects of
man-made chemicals, mainly chlorofluorocarbons used in air
conditioners, refrigerators and aerosol sprays. Governments
agreed to phase out CFCs under the 1987 Montreal Protocol and in
1995 developed countries stopped producing them.
     But CFCs take up to eight years to reach the stratosphere,
where they trigger a chemical reaction that eats away ozone. So
no improvement may be seen in the layer until 2010 although
there is already evidence the damage is growing no worse.
     The effects of the ozone hole on humans are still largely in
the realm of speculation, but studies suggest they are felt far
from Antarctica. In Britain, for example, the risk of developing
skin cancer has risen by as much as 10 percent because of higher
ultraviolet radiation, the Department of the Environment said
last year.
     In southern Chile and Argentina, the only populated areas
directly under the ozone hole, UVB radiation levels have been
rising for years. Chile began an aggressive media campaign to
get people to stay out of the sun and use hats and sunblock
during the hole's worst months from September to December.
     Some creatures in Antarctica seem to taking their own
protective measures of sorts. Arizona State University
researchers found that the Antarctic pearl wort, a velvety,
moss-like plant that thrives on rocky islands, develops a
pigment known as a flavenoid that seems to make it more tolerant
of heavy UV radiation.

     How and why this happens is unknown, but the study
"suggests these plants adapt to UV in ways that some plants can
do, and some can't," said Chris Ruhland, one of the
     "Ultraviolet radiation damages DNA replication, that's
clear. But what these studies show is that this species is quite
tolerant of UVB," botanist Xiong Fushen said.
     Some molluscs have been found to carry a UV-absorbing amino
acid that may protect them from the ultraviolet assault "in the
same way that we use sunscreens," said Karentz.
     Studies are hampered by the fact that there was little
detailed microbiological research going on in this area before
the hole was discovered. So scientists have little baseline data
and are studying an already altered environment.
     Work is only starting on how ozone depletion will ripple
through the whole, delicate food balance in Antarctica.
     "We can still only speculate about what might be happening
in Antarctic populations," Karentz said. "The answer to the
big question, the effects of UV on the complex interaction of
species, is still unknown."