Research at the University of Melbourne and the Bureau of Meterology has overturned conventional ideas of ocean circulation.

 

Rather than moving simply in large clockwise (northern hemisphere) and anti-clockwise (southern hemisphere) gyres, the open waters of the southeast Indian Ocean are flowing east-west in bands, University of Melbourne PhD candidate Prasanth Divakaran and colleagues have shown.

 

The findings have important implications for our understanding of all sorts of ocean events from the movements of fish and marine life to the prediction of weather and climate.

 

Mr Divakaran said that ocean eddies—the marine analogues of atmospheric weather systems like tropical cyclones—form off Australia and begin a three-year journey across the Indian Ocean.

 

“They travel along what we call “ocean arteries”, transporting sea-water and biology with them,” he said.

 

On the basis of initial studies of water movement, Mr Divakaran analysed a model of the circulation of the southeast Indian Ocean using advanced computing and new software for visualising the results. He and his colleagues then checked their findings against satellite observations.

 

“New international satellites and modern technologies developed in Australia helped to reveal the previously unknown ocean circulation patterns. The results are also in keeping with some of the latest research from overseas,” he said.

 

The basin-wide ocean currents the researchers identified are organised into alternating bands, which connect the north-south currents on the east and west side of the Ocean similar to the patterns seen on the surface of Jupiter.

 

Recent work on the lobster life cycle around Western Australia has shown that the probability of the crustacean growing into an adult depends on which deep artery of ocean circulation the larvae are swept into.

 

“Understanding the impact of the arteries on ocean heat transport and climate is critical,” Mr Divakaran said.

 

Mr Divakaran’s work is being released for the first time in public through Fresh Science, a communication boot camp for early career scientists held at the Melbourne Museum. He was one of 16 winners from across Australia. He is also presenting his research at the XXV International Union of Geophysics and Geodesy General Assembly in Melbourne this week.