From the Antarctic: Kiwis delve into global warming

By SIMON COLLINS

A dozen New Zealand scientists have set up camp at a remote, windswept point in Antarctica to try to gauge potential long-term effects of global warming.

For up to three months, the team will sleep in polar tents and go without showers and clean clothes, although they will have a larger tent with internal beams for their laboratory.

Their work at Cape Hallett, at the northwest corner of the Ross Sea, 600km north of Scott Base, is the first stage of a 10-year, $1 million-plus Antarctica New Zealand project to study variations in life forms along a 1300km north/south line from Hallett to the Beardmore Glacier in the south.

The five study sites, spaced out down the western side of the Ross Sea and the Ross Ice Shelf, will provide baseline data from which any changes arising from global warming can be measured.

The Ross Sea sites may be particularly vulnerable to higher temperatures because they are dominated by an annual pattern of open sea freezing over with sea ice in the winter and breaking up again in late summer.

Many kinds of marine life are most abundant at the edge of the sea ice, where the sudden summer breakup of ice sparks a dramatic bloom of plankton, which feeds all other sea life.

The bloom is huge because the seasonal sea ice surrounding Antarctica covers a vast 16 million sq km at its peak, twice the size of Australia.

Victoria University Professor Ken Ryan, who is leading the study of algal plankton at Cape Hallett, said the bloom could be seriously affected if warmer temperatures reduced the annual growth of sea ice.

"If the amount that melts each year reduces from 16 million sq km to, say, 10 million sq km, then the total productivity will drop," he said.

"Thirty to 40 per cent of the total plant productivity over the whole world is in the ocean, and 90 per cent of that is phytoplankton."

Antarctica's annual algal bloom accounts for a big chunk of that phytoplankton - microscopic plant-like marine organisms that may start as single cells but transform the sun's energy into the materials of life.

"The algae in, on and under the sea ice is the grass of the sea. It is what everything else relies on as the source of the food chain," Professor Ryan said.

Dr Mary Sewell of Auckland University is leading the study of the next stage up from phytoplankton - the almost equally tiny offspring of sea urchins and starfish which wait in the Antarctic sea as plankton for nine months or more before transforming themselves into their adult forms when the algal bloom provides a food source.

Finally, Dr Craig Marshall of Otago University is studying the larger fish which feed partly on the sea urchin and starfish larvae.

Dr Sewell said the work at Cape Hallett, which has started in the past week, would all be "virgin territory".

"Because there has been so little biology done up there, we don't really know what we are going to find."