A torpedo shaped underwater glider has just completed a 74 day journey through the waters of the Great Australian Bight, returning loaded with information about the bight — along with a few battle scars.
The Integrated Marine Observing System (IMOS) ocean glider made 344 dives, surfacing regularly to transmit data by satellite back to land where oceanographers have been analysing the data. The glider, which traversed over 1,800 km in the eastern Great Australian Bight, collected data on temperature, salinity and other variables from the ocean surface to a depth of 1,000 m.
On at least one dive the glider was attacked by a shark. Bite marks and a damaged oxygen sensor provide evidence the yellow metal object was mistaken for food and preyed upon.
The mission was part of the Great Australian Bight Research Program, a collaboration between BP, CSIRO, the South Australian Research and Development Institute (SARDI), the University of Adelaide and Flinders University. This four year, $20 million research program aims to provide a whole-of-system understanding of the environmental, economic and social values of the Great Australian Bight; providing an information source for all to use.
"This was the third and final mission of the ocean gliders into the Great Australian Bight for the research program to reveal the secrets from the deep regarding this dynamic and amazingly productive body of water," said Dr Steve Lapidge, the program’s Research Director.
"Judging by the tooth marks on the glider, it appears that one of the locals wants to protect its secrets," he said.
The three glider missions into the Great Australian Bight have helped identify the major current systems, including an eastward flowing South Australian current and the westward flowing Flinders Current, which can be distinguish based on depth integrated currents and temperature/salinity signature.
Dr David Griffin of IMOS OceanCurrent has been developing maps to track the glider’s mission. He has produced an animation which shows the journey of the glider and the measurements taken during its 70 plus days at sea.
A separate glider mission on the Bonnie coast has revealed very strong upwelling of cold water along the coast this summer. Combined, the results of the geographically separated glider missions have provided valuable information about the origin of cold water which results in the high productivity of the Great Australian Bight that underpins South Australia’s important fishing industry.
Tim Moltmann, Director of IMOS, is pleased to see that insights such as these have resulted from the deployment of its gliders.
"The Great Australian Bight Research Program is a great example of an industry-government collaboration using the IMOS national infrastructure to increase our knowledge of marine systems and ultimately benefit the Australian people," said Mr Moltmann.