Over The Horizon

Research at the Last Frontier

Spare some thought for those New Zealand scientists currently stationed in Antarctica where temperatures over the past six weeks have reached as low as -50^o. Researchers from NIWA (the National Institute of Water and Atmospheric Research) have been camping in tents about 100 kilometres from Scott Base in the Dry Valleys.

These ice-free oases, covering 4,800 square kilometres, are one of the harshest and most unusual environments on earth.

Scientists believe the Transantarctic Mountains, inland of the valleys, have risen at such a rate that the Antarctic ice cap -- interwoven glaciers radiating out from middle of the continent -- has been prevented from flowing to the sea.

It hasn't rained in this environment for over two million years, and any snow that falls is quickly blown away by the strong winds that race through the valleys each day.

The cold, dry desert environment is similar to what might exist on other planets and the dominant lifeform -- cyano-bacteria slimes -- are like the organisms which began life on Earth.

The scientists are studying how the return of sunlight in spring might trigger the primitive plants into activity. Results to date suggests that they may remain active through the four months of winter darkness, somehow gaining energy from chemical processes deep in the lakes. Despite Lake Vanda's cover of four metres of ice, scientists have found the temperature near the bottom, 70 metres down, can reach a warm 22^o through a glasshouse-type effect.

NIWA scientists at Scott Base are also keeping a close eye on the ozone layer, sending the results of daily observations to the World Meteorological Organisation.

Optical measurements from 10 Antarctic stations plus satellite pictures enable researchers to track the seasonal deterioration of the ozone layer. The spring ozone hole over Antarctica developed very rapidly during September to cover about 25 million km2. Ozone levels near the South Pole are about 100 Dobson Units, 65% lower than October levels recorded during the 1960s and '70s.

Despite the Montreal Protocol, which should phase out the use of ozone-destroying CFCs this decade, intense holes in the UV-absorbing ozone layer can be expected for another 20 years. Some of this summer's flights between Christchurch and McMurdo Sound will carry technicians who will collect air samples on route that will be used to check models of atmospheric chemistry, important in predicting climate change.

Scientists from both Canterbury and Auckland Universities will look at the ways Antarctic fish have adapted to living below the sea ice, at temperatures where ice crystals would form in the blood of other species. Natural anti-freeze and reductions in the level of haemoglobin in the blood are some of the ways they have been found to cope. Sea ice will also come under the research spotlight, from its molecular structure to the remote sensing of ice floes from satellites. Industrial Research Limited is interested in the processes by which sea ice doubles the size of Antarctica over winter, breaks up by mid summer and exercises a major bearing on southern hemisphere climates.

Tim Higham is with the New Zealand Antarctic Programme.