Australian scientists find southern ocean's missing link

Aug 16, 2007, 6:35 GMT

Sydney - A current flowing past Sydney is the missing link in a flow that connects all three of the Southern Hemisphere's oceans, Australian scientists said Thursday.

The current plays a crucial role in controlling not only the world's temperature but also the food supply for marine life, scientist Ken Ridgway said. Ridgway works for the government establishment CSIRO, or Commonwealth Scientific and Industrial Research Organisation, which leads the Oceans Flagship research programme.

'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,' Ridgway said.

The newly discovered section of the current has been named the Tasman Outflow, which passes south of Tasmania before flowing to the Indian Ocean.

'That's the missing link,' Ridgway said. 'We've been able to show that the global circulation in the Southern Hemisphere is connected.'

He said the finding bears out observations collected between 1950 and 2002 by ships, automated ocean monitors and satellites.

Scientists call the current that they said girdles the earth the Southern Hemisphere supergyre. It travels about 1,000 metres below the surface. Ridgway said monitoring the supergyre should provide pointers to global climate change.