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New Zealand research on Antarctica shows the frozen continent has actually been home to tiny creatures and plants continuously for tens of millions of years.
Mites, worms, wingless insect-like chronomids and pintails as well as lichens "have the potential to have existed through the glaciation of Antarctica", Massey
University molecular biologist Mark Stevens said yesterday.
With Peter Convey of the British Antarctic Survey, Dr Stevens yesterday published a paper in the international journal Science arguing that many species of tiny animals and plants that survive in Antarctica are likely to be descended from species which evolved in ice-free refuges on the continent.
Other scientists have assumed that during ice ages when sea ice could stretch 2000km out over the Southern Ocean - more than halfway to New Zealand - there was insufficient ice-free land for plant and animal species to survive and evolve.
But the latest research said an exceptional long-term evolutionary persistence, isolation, and striking capabilities to survive global climate change, appeared to be the norm rather than the exception for the terrestrial animals.
At least some habitat in the 3000km-long Transantarctic Mountains stretching out from New Zealand's Ross Dependency had always been ice-free.
Dr Stevens, who has also published separate research on Antarctic springtails - tiny, wingless thread-like insects only a few millimetres long, which live on decaying organic matter - said they were relatively long-lived.
"Those on the Antarctic Peninsula live around four to five times as long as temperate springtails, and we have speculated that in the Transantarctic Mountains they might live for around 17 years," he said.
Some of the springtails and other tiny creatures have actually evolved in their isolated refuges since the giant continent known as Gondwana began breaking up 60 million years ago.
Australia - and the Tasman Rise - did not break away from Antarctica until around 35 million years ago, and when Drake's Passage opened to deep water circulation 28 million years ago, the current that began circling the continent helped to isolate it and begin the freezing process.
Dr Stevens said there was only limited scope for sequencing DNA in the organisms to analyse their evolution, but new computerised "sequencers" were starting to allow the analysis of an entire genome.
"This will certainly open many new and exciting avenues for exploring the evolutionary history of Antarctica," he said.
The work would require the collaboration of geologists, glaciologists, and palaeobiologists with molecular biologists but would enable investigation of species dispersal, colonisation and evolution.
DNA could help scientists establish to what extent some of the Antarctic populations were direct descendants of Gondwana species, how they were related to similar species elsewhere in the Southern Hemisphere, and whether there was evidence of re-population of parts of Antarctica from other southern lands.
Dr Stevens said his work indicated the possibility of other surviving organisms either in Antarctica's sub-surface "lakes" or even deep beneath the ice.
-NZPA
