Dramatic proof of ozone hole's effect

By SIMON COLLINS

The ozone hole is deforming and killing tiny sea urchins deep under the Antarctic ice.

Scientists from Otago University and the University of New Hampshire in the United States have found that ultraviolet radiation, no longer blocked by ozone, is penetrating sea ice 2.5m thick to affect the organisms living underneath.

Some eggs laid by sea urchins are being grossly deformed, their usual near-perfect circular shape distorted like a badly burned human body. Others are dying.

By installing protective screens in some areas and not others, the scientists have been able to show that the radiation is cutting the survival rate of newly hatched eggs by 30 to 40 per cent.

In areas where there was no sea ice and the eggs were exposed on the sea surface, none survived.

"They were really quite dramatic results," said Dr Miles Lamare of Otago University, who presented the preliminary results at the NZ Antarctic Conference in Dunedin yesterday.

The initial research was carried out in Antarctica last summer, and Dr Lamare leaves for the US on Sunday to continue analysing the data with his New Hampshire colleagues.

He said the results were "highly conservative" because the ozone hole over Antarctica this summer was much weaker than in the previous few years.

He plans to repeat the tests next summer, when the ozone hole may be more serious again.

In recent years the ozone hole has formed over Antarctica around September each year, when clouds form in the stratosphere high above the poles and react with chlorofluorocarbons (CFCs) to remove the ozone, which normally blocks ultraviolet radiation.

Dr Steve Wood, of the National Institute of Water and Atmospheric Research, said the world ban on using CFCs in aerosols and fridges would eventually restore the ozone to protective levels, but this would take five to 10 years to show.