Let There Be Dark Where The Ice Creatures Thrive

Sydney Morning Herald

Tuesday January 16, 2007

Wendy Frew Environment Reporter

THE silent majesty of the Antarctic can overwhelm even the most seasoned visitor, with a thousand shades of white leaving one gasping for a glimpse of colour or movement.

But life beneath the ice is very different.

Work being done by a team of scientists from the University of NSW and the Australian Antarctic Division has found the shallow waters under the iceshelf off the coast of the Casey station teeming with tiny animals that thrive in the dark.

Golden tubeworms, giant sponges and brightly coloured anemones as big as your head cover the sea floor, while willowy plant-like creatures drift along with the current. Few fish are to be found but divers are often eye-balled by curious penguins.

When the scientists first slip into the water, through holes cut in the ice, it is so dark it takes several minutes to adjust to the low light.

The dark waters, more like those of the deep sea, have allowed huge colonies of filter-feeding creatures, such as marine worms and bryozoans, or moss animals, to flourish, says the university's Emma Johnston, who is leading the research project.

But all of it may be at risk because rising global atmospheric and sea temperatures are melting the ice shelves, and allowing in more light.

Wherever the ice breaks out, canopy-forming algae are more likely to dominate at the expense of invertebrates, said Dr Johnston, whose PhD students have recently spent several months at Casey.

"There are a lot of animals here that have only been found in the Antarctic," she said. "That makes them very special animals and a special community that you won't find anywhere else in the world. They are also at the base of the food chain."

There is a growing body of research predicting climate change will thin Antarctic and Arctic ice, she said, leading to more ice breakouts and more wave action that breaks up ice.

As the ice disappears, underworld life would be exposed to more and more light and probably die eventually - with possible dire consequences for animals further up the chain.

© 2007 Sydney Morning Herald

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