Seaglider explores ocean

A REMOTELY-operated “seaglider” that rode the East Australian Current (EAC) all the way down from Sydney was recovered off Narooma last week.

The seaglider was in the water 65 days collecting and transmitting data along the way to oceanographic scientists and the whole world.

The free-swimming but unpowered, torpedo-shaped glider has internal weights and wings that can be controlled remotely to manoeuvre it up and down and in out of currents.

We are not sure if Nemo or any of his pals were riding along, but Bruce or some other large toothy creature had a look as is evidenced by scratch marks on the glider.

Oceanographer Dr Robin Robertson from the University of NSW at Canberra said the research was part of ongoing studies into eddies and the separation of the East Australian Current from the coast, as well as internal tides and waves along the NSW coast, and conditions in some of the offshore marine parks in NSW.

She said Dr Chaojiao Sun from the Centre for Marine and Atmospheric Research CSIRO/Perth has predicted from her models that the EAC will be strengthened and extend further south in the future.

“By 2050, the zone that it generally split off the coast is expected to split off the coast further south, but still north of Narooma,” Dr Robertson said.

The data collected by the seaglider is available live and free off the Australian National Facility for Ocean Gliders (ANFOG) website and is broadcast whenever the gliders are in the water for the public to view.

Temperatures, salinities, oxygen concentration and other factors are reported with depth for each dive.

As part of the same program, UNSW researchers have also had two oceanographic moorings that monitor ocean temperatures deployed off Narooma for the past two years.

The oceanographers go out with Narooma commercial fisherman Les Muller in his vessel Janelle every six to eight weeks to service the moorings.

Last Tuesday, the researchers were delivered to the location of the seaglider by Narooma Charters skipper Norm Ingersole on board the vessel Dreamtime on Tuesday.

Norm also took his son Nick and grandson Jordyn along for the ride and the glider was located with relative ease drifting on the surface about 33 kilometres out to sea northeast of Narooma.

More pictures of the glider recovery can be seen on Narooma Charters Facebook page.

Also on board were Dennis Stanley from the University of Western Australia, Dr Robertson, Mona Bahri and Daniel Boettger from UNSW Canberra and Ludovic Grosjean from UNSW Kensington.

Updated GPS positions led Mr Ingersole and the researchers to the seaglider that was recovered without incident.

However, it showed evidence of being bitten or attacked in three places, causing some cracking of the outer shell.

As usual, there was biofouling by barnacles and small crabs were found to be living in the shell at the nose.

This marine life had started to interfere with the sensitive instruments, hence the need to recover it, Dr Robertson said.

Amazingly the glider, along with another, has already been redeployed and is heading back to Narooma where the plan is to recover it again in a few weeks.

Dr Robertson and her crew last week left Narooma and immediately travelled up to Yamba on the North Coast to deploy the two gliders.

“The one we picked up off Narooma has already been carried by the EAC to about Foster,” she said. “It is in the EAC and moving fast!”

You can check progress at www2.sese.uwa.edu.au/~hollings/anfog/

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