Researchers returned to Australia this week after a comprehensive 10-week survey of the Southern Ocean, the Australian Minister for the Environment and Heritage, Senator Ian Campbell, said today.

The Baseline Research on Oceanography, Krill and the Environment — or BROKE-West voyage — was led by the Australian Antarctic Division (AAD) and the Antarctic Climate and Ecosystems Co-operative Research Centre (ACE CRC) and covered more than a million square kilometres of the Southern Ocean off Australia’s Antarctic Territory.

During the survey researchers found temperature and salinity changes in some areas of the Southern Ocean as well as potential new krill populations — the main food source for whales and some seabirds.

“Researchers have found that deep waters in part of the survey area were warmer and had higher salinity levels than previously observed,” Senator Campbell said.

While most sectors of the survey area confirm earlier findings of cooler Antarctic waters and less salinity, the easternmost line of the survey showed an increase in both temperature and salinity.

“This is possibly due to a convergence of ocean fronts and a movement of currents south, and our researchers will undertake further analysis over the coming year to determine why this has happened and what it means for ecosystems in the region,” Senator Campbell said.

“Researchers on the voyage also confirmed the presence of a source of very deep Antarctic waters — among the densest waters found on Earth.

“These waters, known as ‘bottom waters', are so named because they fill the abyssal ocean around Antarctica and are important in carrying oxygen-rich waters and driving global deep ocean circulation.

“A significant finding of the survey was the potential discovery of a new population of krill which is a very important food source for whales and some seabirds,” he said.

Researchers found that krill in the region was more widespread when compared with other areas of East Antarctica, suggesting there may be an oceanic population as well as a coastal population.

Senator Campbell said that BROKE-West had been one of the most comprehensive surveys ever undertaken and would provide answers on a whole range of issues and assist with future planning initiatives for the Southern Ocean.

“This has been a great effort by the Australian agencies and a marvellous example of collaboration between 62 scientists from 14 countries,” Senator Campbell said.

The completion of this survey is the culmination of a 10-year project which means that most waters off the Australian Antarctic Territory have now been investigated by the Australian Government’s $100 million a year Antarctic Programme.