Australia's 'Conveyor belt'

A DEEP sea current flowing past Sydney has been found to be part of a long-sought "missing link" thought to connect all the world's southern oceans. CSIRO scientists who discovered the current say it plays a crucial role in controlling not only the world's temperature but the food supply for marine life around the globe. Dubbed the southern hemisphere supergyre, it travels at depths averaging 800 to 1000 metres. Starting in the Pacific north near New Zealand, it flows towards the Queensland coast, where it bends south. Passing Tasmania, it turns west until it reaches Western Australia, where it splits in two before crossing the Indian Ocean. Then it curves south of Africa and into the South Atlantic. Ken Ridgway, a scientist with the CSIRO Ocean Flagships research program, said yesterday that because the current travelled at great depths its temperature and salinity, as well as the nutrients swept along with the flow, changed little. As a result it played an important role in stabilising the world's temperatures, and ensuring the survival of sea life. Monitoring changes in such a stable system should provide pointers to global climate change. Dr Ridgway said scientists had known about what appeared to be three separate westward-flowing currents in the southern Pacific, Indian and Atlantic oceans. While modelling suggested they should be linked, there was no proof. "We knew about individual bits. We knew about the current east of Australia, but when it reached Tasmania, we didn't know whether it went east or west." The previously unknown section of the current, south of Australia, has been named the Tasman Outflow. "That's the missing link," Dr Ridgway said. "We have been able to show that the global circulation in the southern hemisphere is connected."Identifying such a deep current had taken "thousands and thousands of observations" collected between 1950 and 2002 by ships, automated ocean monitors and satellites. http://www.smh.com.au/articles/2007/08/15/1186857596830.html?from=top5
Go Oz scientists!!!!