Giant cold water eddy off Sydney lowers sea level

SYDNEY (Reuters) - Australian oceanographers have discovered a giant cold water eddy off Sydney which has lowered sea levels almost one meter and impacted a major ocean current.

The eddy, which has diameter of about 200 km (120 miles) and reaches to depth of 1 km (1,100 yards), lies about 100 km (60 miles) off Sydney, said Australia's peak scientific body, the Commonwealth Scientific and Industrial Research Organization (CSIRO).

The CSIRO said the eddy was so powerful it had pushed out to sea the strong East Australian Current, popularised in the hit Hollywood animation "Finding Nemo" and used by sailors in the Sydney-Hobart race down the east coast of Australia.

Shipping traffic and fishing have not been affected.

The CSIRO said what had caused the giant eddy was a mystery. "What we do know is that this is a very powerful natural feature which tends to push everything else aside -- even the mighty East Australian Current," said CSIRO's David Griffin.

The sea surface has lowered by 70cm (27 inches) at its center, the CSIRO said in a statement received on Wednesday.

It said the dip in the surface of the ocean was invisible to the eye, but had been accurately measured by European and U.S. satellites.

"Until 20 years ago we would not have known they (giant ocean eddies) even existed without accidentally steaming through them on a research vessel," Griffin said in a statement.

"However, now that we can routinely identify them from space via satellite, marine scientists can evaluate their role as a source of life in the marine ecosystem."

Ocean eddies can have a life of up to three weeks although similar eddies off South Australia and Western Australia are known to have survived several months, said the CSIRO.