Successful season winds up
Sunday 1 April, 2007
Wilkins Runway is on schedule to accommodate regular flights, and the progress of several major science projects signal a successful season in Antarctica for Australia.
Director of the Australian Antarctic Division Dr Tony Press said that research this summer will provide critical information towards understanding a range of global issues such as climate change, the effects on ecosystems of increased carbon dioxide uptake by the Southern Ocean, estimating sustainable krill fishery quotas and remediation of terrestrial and marine environments contaminated by oil spills in previous times.
A busy work programme at Wilkins Runway near Casey station ensures that Australia's Antarctic Airlink is on schedule to begin regular flights next season.
The Australian Government recently announced that an Airbus A319 will be used on the route between Hobart and Antarctica to carry scientists, support personnel and some equipment south in just under five hours, compared with more than a week by ship.
"While shipping will still be used to supply stations and carry heavy equipment, helicopters and some expeditioners we are looking to transport most scientists by air. The time saved by flying will greatly benefit scientists," Dr Press said.
Amery Ice Shelf 'loose tooth'
Scientists have installed a number of broadband seismometers and 'creep meters' at the site of the 'loose tooth' on the Amery Ice Shelf – the largest in East Antarctica - between the Davis and Mawson stations. The creep meter, to stay over winter, will directly measure the amount of opening of an active rift near its tip. This information will be used back in Australia and the United States by scientists working on this collaborative project which brings together experts from the Antarctic Climate and Ecosystems Cooperative Research Centre, University of Tasmania and the Scripps Institution of Oceanography in California.
The so-called 'loose tooth' covers an area of around 900 square kms of the Amery Ice Shelf and has been an area of interest to Australia since the first rifts started to develop in 1995. Since then the two rift systems have been moving at a rate of around four to eight metres a day and opening episodically by some cm every 10-30 days.
Heading the project, Professor Richard Coleman of the University of Tasmania, said that this research will provide a clearer idea on the mechanics of ice shelf rifting.
"To predict what is going to happen to the Antarctic ice shelves in a warming climate, it is critical to incorporate the calving process in a correct manner. Currently, calving is very crudely included in the models, therefore we cannot make accurate predictions," Professor Coleman said.
Close monitoring of the Amery rift system began in the 2002/03 summer to get a clearer idea of why the rifting occurs and what causes ice shelves to break off to form of icebergs. The last major iceberg calving of Amery was in 1962/63. The next event may occur in around five to seven years, although there is no accurate way of knowing how large that calving might be.
Southern Ocean marine science
The Sub-Antarctic Zone Sensitivity to Environmental Change voyage spent five weeks in the Southern Ocean studying the effects of increasing carbon dioxide on planktonic organisms – the microscopic plants and animals in the ocean - and the ability of the ocean to continue to process carbon. The Southern Ocean is a perfect setting to study the effects of ocean acidification as carbon dioxide is more readily absorbed by colder waters than warmer waters.
The project, coordinated through the Australian Antarctic Division, Antarctic CRC and CSIRO, brought together 60 scientists from seven countries to examine planktonic organisms such as certain algae and snail-like pteropods for the effects of acidification which can hinder the development of shells in some species.
The findings from this research will provide critical information on the processes that govern the ocean's natural uptake of carbon dioxide, the ocean's ability to continue to process carbon dioxide, and the likely impacts of acidification on the organisms that form the base of the food web in the Southern Ocean.
Krill distribution research aids in sustainable fisheries
The long-running Adelie penguin monitoring programme at Bechervaise near Mawson station is providing useful information on krill abundance. Adelies are large consumers of krill and useful indicators of the effects of changes in krill abundance brought about by harvesting.
In 1991, the Commission for the Conservation of Antarctic Marine Living Resources (CCAMLR) established an international programme to monitor the impact of the krill fishery on the Southern Ocean ecosystem and assist sustainable management.
Australia then set up the Bechervaise Island Adelie monitoring programme to study the effects of krill abundance on these important predators. An automated system was installed to measure the time the penguins spend at sea foraging for krill, their weight change throughout the breeding season, and the amount of food brought back for their chicks. The successful system continues today.
To further assist in the collection of data, the Australian Antarctic Division recently developed an automated camera, powered by solar panels, to monitor aspects of Adelie chick survival and breeding chronology. During the winter months the cameras 'sleep' then 'awaken' as the summer returns to record a series of photographs throughout the breeding season.
This season, six cameras were installed at new island sites in the Mawson region. This will give us access to information over a much broader area than Bechervaise alone. This will provide a more comprehensive picture of the needs of penguins in this study.
One major aim of CCAMLR is to ensure that the human harvest of krill does not adversely affect any element of the Southern Ocean Antarctic marine ecosystem. Further details will be available as the data are analysed.