< New IMOS Ocean portal launched today
18.04.2012 06:17 Age: 6 yrs
Category: BlueWater, IMOS, ABOS

New EAC mooring array completes the IMOS bluewater observing system

This final mooring deployment means IMOS is observing Australia's deep oceans from the tropics to Antarctica.

These orange buoys awaiting loading on the Marine National Facility,
Southern Surveyor, will be central components in the deep ocean
mooring systems being deployed across the East Australian
Current. Credit, Craig Macaulay, CSIRO

Bernadette Sloyan and Ken Ridgway, with ocean engineers Danny
McLaughlin and Jamie Derrick, who will deploy the deep ocean
moorings. Credit Craig Macaulay, CSIRO

Ocean currents surrounding Australia. Credit: CSIRO


The deep water mooring array was deployed in April this year from the MNF Southern Surveyor to measure the East Australian Current (EAC).

This latest deep water mooring array will complement existing IMOS observations being taken off the Great Barrier Reef, the New South Wales coast, and the east coast of Tasmania.  With this final piece of the jigsaw in place, Australian scientists will for the first time in history have the ability to accurately measure transport of mass, heat and salt from the tropics to the Southern Ocean, to see how it is changing over time, and to understand what these changes might mean for marine ecosystems and coastal populations along the eastern seaboard.  

Lined with sensors recording temperature, salinity, nutrients and velocity of the current, five sets of moorings were deployed across the current, extending 240 kilometres east of Brisbane .The largest of the East Australian Current moorings will be located at a depth of nearly five kilometres below the surface.

Hobart-based scientists, Ken Ridgway and Dr Bernadette Sloyan, specialists in coastal currents in the Australian region led the voyage that deployed the moorings. Mr Ridgway said the East Australian Current is a significant natural resource for Australia and understanding its physical and chemical characteristics as recorded through the mooring network will be important for future natural resource management.

Mr Ridgway said scientists have been studying the East Australian Current for perhaps 100 years, although for the first 60-70 years the focus was on the biology and how it may be influenced by the current.

“In the last 25 years real advances have been made in understanding the chemical make-up of the East Australian Current, its physical structure and seasonal changes, and more recently its influence on the biodiversity of the east coast.

“What we have also seen in that time is a strengthening of the winds in the Pacific that have intensified ocean circulation and are pushing the current around 350 kilometres further south in the Tasman Sea.