07 August 2012
South Australian Museum Scientist Dr Mark Stevens is describing a new species of springtail – the largest known land animal living on continental Antarctica all year round.
It's the first new species of springtail to be found in the Transantarctic Mountains for nearly 50 years and the first to be found on continental Antarctica for 34 years.
Dr Stevens has collaborated with Dr Ian Hogg from New Zealand who collected the specimen on a field trip to the Mountains over summer.
"At 84 degrees south, this region was known to have three species of springtail and they were described in the '60s. Now we've started to look at the morphology of the animal and it is very different to the others. So now we're describing the first new species in over 40 years from this region of Antarctica and it's very exciting," says Dr Stevens.
At one to two millimetres long, springtails are tiny, but considered the "megafauna" of Antarctica.
Dr Stevens is no stranger to taking on the world's harshest conditions and has been studying the Antarctic ecosystem with Dr Ian Hogg since 1998.
They are surveying the biodiversity of the Transantarctic mountains and the Australian East Antarctic Territory to understand what life exists on the icy plains and why.
Until quite recently, biologists thought that most of the life found on Antarctica arrived on the continent within the last few thousand years. But the DNA of soil organisms now shows that some of them have been around a lot longer. In fact, scientists think they've been there since Antarctica broke away from the ancient super continent Gondwana about 135 million years ago.
"They used to be classed as insects but now they have a class of their own – Collembola. They're a springtail because of the little spring organ that sits on the underside of the abdomen so when they're surprised or they just want to move from one spot to another, that releases and they spring off," says Dr Stevens.
"Collembola have a spring organ, six legs and segmented bodies. They also have a ventral tube which is one of the key characteristics. It helps them stick to surfaces and it can secrete a fluid which then goes up a central line to the mouth. This potentially enables them to rehydrate their bodies and cope with dry habitats like cold polar deserts."
The team are using sophisticated DNA technology to explore Antarctica's biodiversity. Rather than collecting the tiny animals from the ground by hand, they take soil so that they can extract DNA from it later, back in the lab. The scientists use satellite imagery in a GIS-platform, dividing the ice-free terrain into tiles to work out where to take samples from.
The method is already showing positive results.
"We have found more diversity than previously recognised and the methods are revealing insights into why life exists in some locations and not others. Also, we have been exploring the links between isolated pockets of land and found that several species thought to be cosmopolitan are not, and vice versa," he says.
"Identification of true levels of biodiversity will answer important questions such as 'what is there?' and 'how is it different?' This is important for managing specially protected regions, but also acts as a baseline so that we can detect introductions (if we didn't know what was there in the first place, we wouldn't know if it's introduced or not), and also to track biotic changes with climate - past and future."
Surviving in Antarctica
The wind chill can take the temperature down to -60ºC, so Dr Stevens and his crew have had to become survival experts on the icy continent.
"You've got jackets and footwear and everything that protects you from the cold, wind and also the sun. You're there in 24 hours' daylight, so protection from getting not only burns from the wind and the cold but also sunburn and with a lack of ozone layer, you really have to protect yourself."
They sleep in pyramid-shaped tents, which protect them from the wind, and eat dehydrated, frozen or semi-dried foods that have been prepared back home. Although supplies are better than those available for early explorers such as Sir Douglas Mawson, Dr Stevens says conditions are still harsh.
"You lose a fair bit of weight, especially after walking about 20 kilometres during the day. You use up a fair bit of energy. One season I lost about 11kg across two and a half months, just walking around but still eating really high energy foods, but you just use it up."
Getting to Antarctica is an expensive journey and sometimes conditions are too perilous for scientists to stay there. The team has to pay close attention to the weather and make sure they have everything they need to survive the freezing adventure.
About Dr Stevens' work
Based at the South Australian Museum's Science Centre (off Kintore Avenue, Adelaide), Dr Stevens' research has a strong focus on Collembola invertebrates, but also Crustacea and Hymenoptera. Dr Stevens works regularly on species groups in the southern hemisphere and studies in Australia, New Zealand, Antarctica and sub-Antarctic islands.
He was the first scientist to investigate the correlations between molecular dating, geological and glaciological hypotheses for continental Collembola. This work revealed a collembolan fauna that was likely to have been present on the Antarctic continent as it became glaciated and have remained there since.
At the South Australian Museum
Members of the public can see items collected from early explorers as part of the Australian Polar Collection. The collections on display from expeditions by Sir Douglas Mawson (1852–1958) and John Riddoch Rymill (1934–1937) include animal specimens, maps, survival equipment, papers and photographs. At more than 100,000 items, this collection boasts the largest number of artefacts from Sir Douglas Mawson in the world. The enviable display has attracted worldwide attention and allows visitors a hands-on experience of the explorer's adventures and scientific expertise.