“I think Tasmania has a real critical mass in terms of Antarctic robotic research that we are capitalising on,” the Australian Maritime College’s Dr Alex Forrest said.
Dr Forrest has just returned from Antarctica where he worked with the Institute for Marine and Antarctic Studies’ Dr Vanessa Lucieer in the deployment of an autonomous underwater vehicle (AUV), the UBC-Gavia, to study the underside of sea ice.
“While the Gavia is very good at going under sea ice and doing small-scale measurements, it’s not very good at large-scale measurements,” Dr Forrest explained.
So the idea is to build a new vehicle capable of travelling hundreds of kilometres and we have funding in the order of $7.5 million to do that.
Dr Forrest and Dr Lucieer were part of a team of seven researchers who spent late October at Cape Evans in the New Zealand-managed territory accessed from Scott Base investigating and characterising the conditions beneath sea ice. The project is a collaboration between the two University of Tasmania institutes, the AMC and IMAS, and the University of Canterbury (New Zealand) and Aarhus University (Denmark), with funding from the New Zealand Antarctic Research Institute.
It involved mapping the first stages of microscopic life forms, either clinging to the underside of sea ice or free-floating in the dark frigid waters. These life forms are the basis of the marine food chain that ultimately supports the mega-fauna of whales and seals.
Sea ice is of global significance, playing important roles in ocean circulation and the functioning of polar ecosystems. Flying in their key hardware, UBC-Gavia and a remotely operated vehicle, the Seabotix, the team dealt with the challenges of surveying from a Ross Sea ice hole at North Bay.
We are creating history for future marine scientists and resource managers and giving them a legacy of information
“UBC-Gavia has a sophisticated geo-referencing system and is totally autonomous,” Dr Lucieer said. “It will fly under the sea ice mapping the underside of the Antarctic ice sheet, measuring ice topography with high-resolution acoustics and, among other things, sample chlorophyll and fluorescence, water temperature, and salinity, and velocity, as well as acoustic sidescan and optical backscatter measurements.
“The ability to measure all of these parameters simultaneously while maintaining fixed elevation from the ice sheet at six metres provides an unprecedented opportunity to map this unique environment.”
Dr Forrest said the data would allow scientists to characterise the under-ice environment that hosts algal species living on its surface. “However, inaccessibility makes it hard to quantify its properties at meaningful spatial scales. Autonomous underwater vehicles can measure horizontal variability in sea-ice properties at near centimetre resolution along kilometres of trackline, offering a fundamentally new approach to sea-ice research.”
The Gavia has been instrumental in several coastal science projects since being brought to Tasmania from Canada by Dr Forrest two years ago. It had a $260,000 upgrade before its Antarctica deployment.
In a 2013 study of sea urchin barrens in north-east Tasmanian waters, its value in data-gathering was quickly demonstrated, both in the survey areas it was able to cover and the high-quality resolution of the acoustic and visual images it created. These come from acoustic transmissions from the instrument to the seafloor. A single deployment will collect thousands of depth soundings, which are used to construct maps of the seafloor, including topography and the ability to help identify aquatic vegetation.
The Gavia has also been pivotal in surveys of offshore infrastructure.
“There’s so much detail on terrestrial maps, and yet until the last decade we were lucky if we could source any accurate underwater data from which to tell stories about the seafloor and related water column,” Dr Lucieer said.
“With this technology, we are creating history for future marine scientists and resource managers and giving them a legacy of information that people previously wouldn’t have had the opportunity to know about.”
Cash injection
The Antarctic Gateway Partnership’s funding of $24 million will complement research programs and priorities developed in Australia’s Antarctic Science Strategic Plan to understand the role of Antarctica and the Southern Ocean in the global climate system, according to the chief investigator Professor Richard Coleman, from IMAS.
“The Partnership will provide an important injection of funds and an exciting capacity-building development that will expand research programs in a climatically and ecologically significant region and reinforce recognition of Tasmania as a global leader in Antarctic and Southern Ocean science,” he said.
“Importantly, the Gateway funding is providing the opportunity to get more scientists to the ice.”
The Partnership is funded by the Australian Research Council and brings together IMAS, the AMC, the CSIRO’s Oceans and Atmosphere Flagship and the Australian Antarctic Division.
For more information, visit seamap.imas.utas.edu.au