New Sea Creatures Never Been Seen Before
Bizarre carnivorous sea squirts, large spider-like creatures and an ancient fossilised coral reef have all been found in a voyage into ultra-deep Australian waters.
The scientific examination Chronology of the Tasman Fracture, a 4km-deep crack in the earth's crust off the coast of Tasmania's southwest, has led to the discovery of creatures never seen before.
"A thing that was really surprising was the diversity of life down there," said Dr Ron Thresher from the Commonwealth Scientific and Industrial Research Organisation (CSIRO), who took part in the trip.
"We really didn't know what to expect in these really deep areas. It could have been anything from bare mud to lush communities. It was really a shot in the dark."
Never before have lifeforms at such depths in Australia's oceans been studied.
Using a remotely operated submarine about the size of a small car to collect samples and data, the scientists took photos and film at different depths.
At up to 3000m were thousands of sea spiders, creatures about 30cm in diameter that look like land spiders but are unrelated.
At 3500m were millions of sea anemones, Thresher revealed.
"They had never been described before. They had never even been observed before," he said.
"The entire bottom was covered in these things as far as you can see and it was just completely unexpected to see this huge dominant community down there."
Expedition leader Jess Adkins, from the California Institute of Technology, said the deepest life forms observed were anemones living down at about 4050m.
"Almost immediately we saw there were things living in the sediment," Adkins said.
There were also carnivorous sea squirts half a metre high, which trap small fish and other creatures, and differ from most other sea squirts, which filter feed.
In depths from about 1000m to shallower water was a reef of black, dead coral that dated to more than 10,000 years old.
But one of the scientists' most bizarre discoveries was what they did not find on the ocean floor.
Thresher said the team of Australian and US researchers who took part in the US$2 million ($3.72 million) voyage had expected to find coral skeletons that were hundreds of thousands of years old lying in very deep depths.