Media release: 22 March 2008

The final sailing south in the world’s largest Southern Ocean climate experiment gets underway today when the Aurora Australis sets sail from Hobart.

Aurora Australis is the last of 20 international research vessels deploying instruments in the Southern Ocean as part of an International Polar Year (IPY) experiment known as CASO, for Climate of Antarctica and the Southern Ocean.

The Antarctic Climate & Ecosystems Cooperative Research Centre (ACE CRC) is leading the voyage, which includes a team of researchers from the Centre’s partner organisations includ- ing the Alfred Wegner Institute (Germany) and the National Institue of Water and Atmospher- ic Research (New Zealand).

“By pooling resources, scientists from 18 nations will be able to take a ‘snapshot’ of the phys- ical, chemical and biological state of the entire Southern Ocean for the first time,” says voy- age leader and ACE CRC program leader, Dr Steve Rintoul.

“In the 1990s scientists took nearly a decade to complete a similar survey as part of the World Ocean Circulation Experiment. The IPY gives us a chance to carry out an even more comprehensive program in a single season, providing a much clearer picture of how the Southern Ocean is changing.”

“The basic question motivating this research is whether the Southern Ocean is changing, and if so, what are the consequences for climate and biodiversity?”

The CASO program is using ships, autonomous profiling floats, moorings, satellites and oceanographic sensors mounted on seals to study the Southern Ocean during the IPY. Mea- surements made on the Aurora Australis will also contribute to a number of other IPY pro- grams studying the physics, chemistry and ecology of the Southern Ocean.

“To understand how the Southern Ocean will drive and respond to climate change and the im- pacts on marine ecosystems, we need to simultaneously measure the physical, chemical and biological conditions. The IPY gives us an opportunity to do this over the vast expanse of the Southern Ocean,” explains Dr Rintoul.

The Southern Ocean is one of the few places in the world where conditions are right to make surface water sink into the deep ocean, a key link in the global system of ocean currents that controls climate.

“One of the key places to look for changes in ocean properties is at the bottom of the South- ern Ocean, where this dense water is found. Our expedition will target a cross-roads of 2 of the 3 major sources of dense bottom water, so we can assess how rapidly this important part of the ocean is changing,” says Dr Rintoul.

The Southern Ocean acts to slow the rate of climate change by absorbing large amounts of carbon dioxide from the atmosphere.

“Recent studies suggest the Southern Ocean may be becoming less efficient at soaking up carbon dioxide and transporting it to the deep ocean. Our measurements of how much carbon dioxide is accumulating in the ocean and whether the ocean circulation is changing will pro- vide a critical test of this hypothesis.”

Growth of phytoplankton, the base of the Southern Ocean food chain, is limited by the amount of iron dissolved in sea water. Scientists onboard Aurora Australis will use special ultra-clean techniques to make the first measurements of iron concentrations along a full transect from Australia to Antarctica, as part of the IPY GEOTRACES program.

Supported by CSIRO’s Wealth from Ocean Research Flagship and the Australian Antarctic Division, scientists from Australia will join counterparts from France, the UK and the USA to conduct experiments on Aurora Australis over the next four weeks.

This will be the third voyage by the vessel as part of the International Polar Year, with previ- ous voyages studying sea ice processes and biodiversity as part of the Census of Antarctic Marine Life.

CSIRO Fellow Dr Rintoul co-chairs the international CASO program and leads the Climate Variability and Change program at the Antarctic Climate and Ecosystems Cooperative Re- search Centre. He will be the Voyage Leader and Chief Scientist on the Aurora Australis.

For more information:
Jess Tyler, Communications Manager
Antarctic Climate & Ecosystems Cooperative Research Centre
Tel: +61 3 6226 2265 • M: 0419 315 381 • E: This e-mail address is being protected from spambots. You need JavaScript enabled to view it

The Antarctic Climate & Ecosystems Cooperative Research Centre (ACE CRC) is a collaborativepartnership dedi- cated to the study of atmospheric and oceanic processes of the Southern Ocean, their role in global and regional climate change, and their impact on sustainable management of Antarctic marine ecosystems. The ACE CRC’s core partners are the Australian Antarctic Division, the Australian Bureau of Meteorology, CSIRO Marine and Atmo- spheric Research, and the University of Tasmania. Supporting partners are the Alfred Wegener Institute for Polar and Marine Research (Germany), the Australian Greenhouse Office, the Australian National University, the National Institute of Water and Atmospheric Research (New Zealand), Silicon Graphics International, and the Tasmanian Department of Economic Development.

Established and supported under the Australian Government’s Cooperative Research Centre Programme