Researchers from Australia, France and Japan have returned to port from the Southern Ocean following a two-month jaunt to probe the icy depths, which yielded some impressive footage of the abyss as well as a range of hitherto-unknown Antarctic sea monsters.

Oz's Aurora Australis joined France's L'Astrolabe and Japan's Umitaka Maru on the "census of life" dubbed the "Collaborative East Antarctic Marine Census" (CEAMARC). While the French and Japanese ships busied themselves with examining the mid and upper ocean environment, Australian researchers concentrated their efforts on the ocean floor.

Aurora Australis head boffin Dr Martin Riddle says that the vessel's expedition uncovered "a remarkably rich, colourful and complex range of marine life in this previously unknown environment".

He added: "Some of the video footage we have collected is really stunning – it's amazing to be able to navigate undersea mountains and valleys and actually see what the animals look like in their undisturbed state.

"In some places every inch of the sea floor is covered in life. In other places we can see deep scars and gouges where icebergs scour the sea floor as they pass by. Gigantism is very common in Antarctic waters – we have collected huge worms, giant crustaceans and sea spiders the size of dinner plates."

CEAMARC, the Australian Antarctic Division explains, forms part of the international Census of Antarctic Marine Life which it coordinates, and will involve 16 voyages to Antarctic waters during the "International Polar Year" of 2007-2009.

The census will "survey the biodiversity of Antarctic slopes, abyssal plains, open water, and under disintegrating ice shelves", and aims to "determine species biodiversity, abundance and distribution and establish a baseline dataset from which future changes can be observed".

Riddle elaborated: "This survey establishes a point of reference to monitor the impact of environmental change in Antarctic waters. For example, ocean acidification, caused by rising atmospheric carbon dioxide levels, will make it harder for marine organisms to grow and sustain calcium carbonate skeletons.

"It is predicted that the first effects of this will be seen in the cold, deep waters of Antarctica. Our results provide a robust benchmark for testing these predictions."

There are links to more pictures and movie material of the Southern Ocean's depths here. ®

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