Rare visit to remote Southern Ocean territory finds changes
15 January 2009
The Australian Antarctic Division has released some rare pictures of Australia's remote World Heritage listed Territory of Heard Island and McDonald Islands (HIMI), located in the Southern Ocean some 4000 km south-west of Western Australia.
The Australian Antarctic Division recently visited the islands on the research ice-breaker Aurora Australis and discovered visible changes which reflect the highly dynamic HIMI landscape.
In the most obvious change, a sand spit at the eastern end of Heard Island had been inundated by the ocean creating an "island" of what satellite images from early last year showed to be a section of land hanging on by a thread.
"It's a very dynamic landscape, being home to two active volcanoes, and its Southern Ocean isolation means visits are rare," Heard Island expert Ewan McIvor said. The Australian Antarctic Division's last major expedition to the island was in 2003/04 when significant glacial retreat was recorded at Brown Glacier.
"Satellite imagery has been showing the islands are constantly changing. In 2004 remote sensing showed volcanic activity on McDonald Island, some 44 km west of Heard Island, had doubled in size from about 1 square km to 2.5 square km.
"While weather conditions prevented us getting any pictures of the changed McDonald Island this visit, it was very interesting to see the changed landscape in the area of Heard Island known as Elephant Spit. At our last visit this still joined to the mainland," Mr McIvor said.
The Australian Antarctic Division manages the islands and 65,000 square kilometre marine reserve which lie in the direct path of the "furious 50s", and are a technically challenging and expensive place to visit. The dynamic environment and the minimal modification from human visitors makes Heard Island an important location for Australian climate change research.
During the brief but valuable visit, the Australian Antarctic Division expeditioners were able to complete some aerial, ship-based and terrestrial photographic surveys to detect environmental change; inspect some of Heard island's heritage sites; check and maintain scientific equipment, and make sure refuge huts were still sound. The Aurora Australis was also able to collect further bathymetric data to improve charting in the region.
The information collected will provide important insights into the status of Heard Island's glaciers, lagoons, ice-free areas, vegetation and wildlife colonies, and will contribute to AAD's responsibilities for monitoring and managing this unique and spectacular southern outpost. Information collected will feed into an AAD project currently underway to develop computer analysis techniques to detect environmental change at HIMI from satellite images.