Deep-sea sub discovers new animals off Australia

A deep sea submarine exploration off Australia's southern coast has discovered new species of animals and more evidence of the destructive impact of the greenhouse gas carbon dioxide on deep-sea corals.

The scientific voyage by US and Australian researchers explored a near vertical slice in the earth's crust known as the Tasman Fracture Zone, which drops from approximately two kilometres to more than four kilometres deep.

"We set out to search for life deeper than any previous voyage in Australian waters," said Ron Thresher from Australia's Commonwealth Scientific & Industrial Research Organisation (CSIRO).

"Our sampling documented the deepest known Australian fauna, including a bizarre carnivorous sea squirt, sea spiders and giant sponges, and previously unknown marine communities dominated by gooseneck barnacles and millions of round, purple-spotted sea anemones," Dr Thresher said in a statement.

Vast fields of deep-sea fossil corals were also discovered below 1.4 kilometres and dated more than 10,000 years old.

The four-week expedition deployed a deep-diving, remotely operated, submarine named Jason, which belongs to the Woods Hole Oceanographic Institution in the US.

Jason is about the size of a small car and was capable of collecting samples, and photographing and filming areas as deep as six kilometres. Jason made 14 dives lasting up to 48 hours each and reaching a maximum depth of more than four kilometres.

The researchers, from the California Institute of Technology and CSIRO, said some of the deep-sea coral discovered was dying and they had gathered data to assess the threat of ocean acidification and climate change on Australia's unique deep-water coral reefs.

"We need to closely analyse the samples and measurements we collected before we can determine what's caused this, as it could be the result of several factors, such as ocean warming, disease or increasing ocean acidity," said Dr Thresher.

Carbon dioxide spewing into the atmosphere by factories, cars and power plants is not just raising temperatures, but also causing what scientists call "ocean acidification" as around 25 per cent of the excess CO2 is absorbed by the seas.

Australian scientists have already warned that rising carbon dioxide levels in the world's oceans due to climate change, combined with rising sea temperatures, could accelerate coral bleaching, destroying some reefs before 2050.