SYDNEY (AFP) – Scientists said Sunday they had uncovered new marine animals in their search of previously unexplored Australian waters, along with a bizarre carnivorous sea squirt and ocean-dwelling spiders.
A joint US-Australian team spent a month in deep waters off the coast of the southern island of Tasmania to "search for life deeper than any previous voyage in Australian waters," lead researcher Ron Thresher said.
What they found were not only species new to science -- including previously undescribed soft corals -- but fresh indications of global warming's threat to the country's unique marine life.
One of Australia's deepest residents a carnivorous sea squirt, or ascidian, standing half a meter tall on the seafloor on the Tasman Fracture Zone at a depth of 4006 metres. (Photos AFP/HO/Ho)"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," Thresher said.
Using a submersible car-sized robot named Jason, the team explored a rift in the earth's crust known as the Tasman Fracture Zone, a sheer two kilometre (1.24 mile) drop to 4,000 metres (13,200 feet) below the ocean's surface.
Blogging on board the ship, researcher Adam Subhas said the team witnessed some "cool biology" as they descended the fracture, including the sea squirt, which he described as "basically an underwater Venus fly trap, but much bigger."
The sea squirt, also known as an ascidian, stands 50 centimetres tall on the sea floor at a depth of just over 4,000 metres. It traps prey in its funnel-like front section if they touch it when they swim past.
"The geology was fascinating too -- the sediment was incredibly fine and lightly packed; it made me think of powder snow," Subhas wrote.
Fossil coral fields were found, dating back more than 10,000 years. Thresher said samples taken would provide ancient climate data for use in global warming projections.
"Modern-day deep-water coral reefs were also found, however, there is strong evidence that this reef system is dying, with most reef-forming coral deeper than 1,300 metres newly dead," he said.
Though close analysis of samples was still required, Thresher said modelling suggested ocean acidification could be responsible.
"If our analysis identifies this phenomenon as the cause of the reef system's demise, then the impact we are seeing now below 1,300 metres might extend to the shallower portions of the deep-reefs over the next 50 years, threatening this entire community," he said.
Rising sea temperatures are blamed on global warming caused by the build-up in the atmosphere of greenhouse gases such as carbon dioxide -- which is also blamed for higher acidity in sea water.
A UN report warned in 2007 that Australia's Great Barrier Reef, described as the world's largest living organism, could be killed by climate change within decades.
The World Heritage site and major tourist attraction, stretching over more than 345,000 square kilometres (133,000 square miles) off Australia's east coast, could become "functionally extinct", the report said.
Deep-sea sub discovers new animals off Australia
Michael Perry, Reuters 17 Jan 09;
SYDNEY, Jan 18 (Reuters) - 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 U.S. and Australian researchers explored a near vertical slice in the earth's crust known as the Tasman Fracture Zone, which drops from approximately 2 km (1.2 miles) to more than 4 km (2.5 miles) 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," Thresher said in a statement on Sunday.
Vast fields of deep-sea fossil corals were also discovered below 1.4 km (1 mile) 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 United States.
Jason is about the size of a small car and was capable of collecting samples, and photographing and filming areas as deep as 6 km (4 miles). Jason made 14 dives lasting up to 48 hours each and reaching a maximum depth of more than 4 km (2.5 miles).
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 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 percent 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. (Editing by Jeremy Laurence)