CSIRO's Dr Ron Thresher holding deep-ocean corals.

CSIRO's Dr Ron Thresher with deep-ocean corals used in the study to assess growth rates in fish species.

Submersible in 2.5 km dive for climate science

Reference: 08/02

Australian and US scientists will next week use an unmanned submersible to locate live and fossilised deep-ocean corals south of Tasmania to track changes in climate in the southern hemisphere.

10 January 2008

Like tree rings, growth rings in corals indicate age. They also reflect changes over centuries and millennia in ocean chemistry and the ocean environment.

The submersible will dive to depths of 2.5 kilometres and spend up to 6-7 hours filming the corals and other biodiversity at that depth.

"Deep ocean corals are a litmus test of the deep ocean when it comes to identifying how temperature and salinity have changed over decades and centuries, especially in our own region in the Tasman Sea and the Southern Ocean," says Dr Ron Thresher of CSIRO’s Wealth from Oceans National Research Flagship, Chief Scientist on the voyage leaving Hobart tomorrow.

"By collecting coral samples around the Tasmanian seamounts reserve and other deep ocean ranges south of the State we hope to track two influential elements on the global climate system - the formation of water masses at the Antarctic coast and the circulation of the Southern Ocean."

“Deep ocean corals are a litmus test of the deep ocean when it comes to identifying how temperature and salinity have changed over decades and centuries, especially in our own region in the Tasman Sea and the Southern Ocean,"

says Dr Ron Thresher of CSIRO’s Wealth from Oceans National Research Flagship.

The platform for research on the 23-day voyage is Australia's Marine National Facility research vessel, Southern Surveyor.

On loan for the voyage will be the Woods Hole Oceanographic Institution Autonomous Benthic Explorer (ABE), specifically designed for survey work to depths of about 4000m and to be used in three locations south of Tasmania: the Tasmanian Seamounts Marine Reserve (now wholly contained within the Huon Commonwealth Marine reserve), the Tasman Fracture Zone and Tasman Rise. The submersible can dive for up to seven hours and its cameras will film locations that can be sampled on a follow-up voyage later in the year.

Joining Dr Thresher will be Principal Research Scientist at the California Institute of Technology, Dr Jess Adkins; ocean engineers from Woods Hole Oceanographic Institution; and CSIRO marine ecologist, Dr Alan Williams, who has been measuring marine biodiversity in Australia’s recently-declared deepwater South-east Commonwealth Marine Reserve Network.

Dr Williams said that a submersible dive below 1,800m will allow scientists to view biodiversity at depths never before seen in the Australian region.

"We have a good sense of the marine ecology around seamounts [submerged volcanoes] down to about 1,500m but to be able to see and build an understanding of life beyond is a tremendously exciting prospect,” he said.

The voyage is part of a collaboration between the Wealth from Oceans Flagship, Woods Hole Oceanographic Institution in the United States, the National Science Foundation in the United States, the marine division of the Australian Department of Environment Water Heritage and the Arts and the Marine National Facility.

National Research Flagships

CSIRO initiated the National Research Flagships to provide science-based solutions in response to Australia’s major research challenges and opportunities. The nine Flagships form multidisciplinary teams with industry and the research community to deliver impact and benefits for Australia.

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