by Sharon Robinson
Australian plants cope with harsh environments but not as extreme as Antarctica. Incredibly, plants survive winter temperatures of -40o C and average summer temperatures of 0o C. Daylength changes from 24 hour sunlight to total darkness in midwinter and winds can gust to over 100 knots. Nevertheless, mosses and liverworts grow on the ice-free rocky coastal outcrops. Lichens are even tougher, surviving on exposed rocks far inland towards the pole. Plant life is far more varied on the relatively benign Antarctic peninsular and the sub-antarctic islands. Anything on the continent must survive life in the freezer most of the year, with summer days resembling an occasional visit to a well-lit fridge!
Moss and lichens survive repeated freezing and thawing. Anyone who has frozen leafy vegetables knows most plants look pretty sick after thawing. Ice in the cells causes the damage. As water freezes, it expands and ice crystals break the cell wall. When the ice melts, the cell collapses. This is usually fatal. Mosses and lichens survive by dehydrating during freezing. They also produce anti-freeze chemicals, preventing ice formation in the cells. Antarctica is a huge frozen desert most of the year, with all the water locked up in ice. The dehydrated plants survive winter buried in ice and grow in summer when the ice melts, providing water.
Australia has a large presence in Antarctica, claiming 40% of the continent, with 3 permanent bases, all on prime ice-free rock real estate. Casey has the richest plant life and in biodiversity terms, is probably the tropical rainforest of Antarctica. These moss communities attract researchers from around the world trying to understand their diversity and survival mechanisms. Unlike the northern hemisphere, no large animals graze the moss, but it is home to countless microscopic invertebrates.
Research is coordinated and largely funded by the Australian Antarctic Division (AAD), in atmospheric and biological sciences, geosciences, glaciology, human impacts and oceanography. A major focus of the biological science program is the effect of global change on antarctic ecosystems. One aspect is the effects of increasing UV-B radiation due to the decrease in ozone over the southern hemisphere each spring. Traditionally, UV levels were low because of the low solar angle at the poles, but ozone depletion means levels are now similar to the tropics in mid summer. Antarctica's plants have faced a large increase in UV exposure over a relatively short time. Fast change is hard for plants to adapt to and given the extreme conditions, this additional stress could be critical for moss populations.
In July 1996 I was awarded a grant from the AAD to visit Casey base in Antarctica for four months to study the effects of UV light on moss species. I had just 2 months to make arrangements, buy materials, organise equipment, attend compulsory medical and psychological testing and survival training before we sailed south. The project is now in its second year and I have been to Casey Base twice, with Wollongong PhD student Jane Wasley, in 96/7 and with co-investigator Dr Cath Lovelock, Smithsonian Environmental Research Institute, USA, in 97/8.
We are investigating how moss copes with increasing UV and how the response to high UV radiation differs from its response to high visible light. Does the moss produce sun-blocking or screening chemicals, or does it rely on efficient mechanisms to repair DNA damage? These studies will help us to understand responses to global climate change and how moss is likely to fare in coming decades.
We use screens to either block or transmit UV-light and also shade cloth to reduce overall light levels. These screens must survive 100 knot winds and winter snow. We perfected our design the first summer and the screens withstood several blizzards. But we realised one spring was too short to see significant changes and the screens should remain for a year. As science programs undergo environmental impact assessment, we modified our proposal and returned to Casey for two months the following summer to put the screens in again, this time for a year.
This winter Meteorology technician Adrian Porter monitors them and sends monthly reports of snow precipitation, measures snow cover on the screens and provides digital pictures of the screens (or the snow, see web page). We will return in 98/9 for final samples. We are analysing initial samples and data from the first two seasons.
Women have been able to winter in Antarctica for almost 20 years and the AAD wants to increase the proportion of women at its bases. Each permanent station has a 'winter' group of about 16 people, responsible for day-to-day running over the year. The majority are tradespeople, the doctor, chef, station leader and communications officers, observers and Bureau of Meteorology (BOM) technicians and often a lone physicist as resident scientist.
In summer most bases overflow as scientists descend. Large maintenance crews may be completing building programs and some bases have weather forecasters. In winter, only one or two women (12 % of the station population) live at Australian bases. That figure increases to 25-33% in summer. Women often form a large proportion of science programs, particularly in Human Impacts and Biological Sciences. At Casey last year 25% of physicists and 50% of biologists and human impacts scientists were women, however there were no women glaciologists. Women are well represented on BOM, medical and catering staff and are, occasionally, Station Leaders. But women are in a minority and this is likely to continue until they are better represented in trades.
It is impossible to generalise about attitudes to women at the bases. It varies with changing personnel. Overall group size, relative proportions of professional and scientific personnel and mean age and experience all contribute. Some years see a very close community and in others there will be numbers of small groups with tradespeople and scientists hardly mixing at all. There can be a "blokey" atmosphere but most people want to work together and support the programs. The harsh environment means your survival depends on everyone else, building a strong community sense.
Some women manage their own research programs in Antarctica. Others are volunteers. A lone tradeswomen would have a different experience to mine, as a scientist working on my own project. I valued the chance to meet people with very different life experiences and to participate in new activities, including designing and building my own equipment in workshops, driving huge oversnow vehicles and learning to cross crevasses safely to remote field sites. It can also involve new recreational activities such as skiing, climbing and photography. The bases let women show exactly what they can do which promotes equal opportunities in a practical way. A sense of humour is probably the most important attribute. The most difficult adjustment was the small community atmosphere and the extra attention this entails. It is ironic Antarctica is one place you are never alone.
Antarctica is one of the last great wildernesses and visiting it as a scientist is a rare and fantastic experience. Much of it is pristine and away, from the bases, remains much as it always has been. However, tourism is increasing and we must ensure both the bases and transient visitors by ship make as little impact as possible. Environmental awareness is relatively high, but this hasn’t always been so. Nowadays station rubbish is sorted into glass, aluminium and other metals and returned to Australia (RTA). For health reasons medical and food waste are incinerated on site. Field parties obey ‘the take only photos, leave only footsteps’ rule and human waste is brought back and incinerated. However, in the past rubbish was left in open tips and because of the cold remains largely intact after decades. Sewage receives primary treatment but is discharged into the bay. The Human Impact program is monitoring human activities. This includes effects of vehicles and people on animals as well as the impact of the bases themselves. This is vital to understand how humans affect the animals and plants there and ensure we make us little impact as possible.
As well as bringing back rubbish, there is also heightened awareness about the impact of introduced species on flora and fauna. This is a major issue on the sub antarctic islands, Macquarie and Heard Is. because the more benign environment means introduced pests like rats, rabbits, cats, foxes and plants are more likely to survive and potentially damage native organisms. It is less of a problem on the continent but we still must be aware that organisms may be transplanted. The most insidious are probably microorganisms which may infect animals and plants despite the cold. Poultry products are banned in the field because of concerns that poultry viruses may infect penguin or other bird communities nesting around the bases.
Biological science in Antarctica is not just finding out what is there and how organisms survive the already harsh, and potentially worsening conditions arising from global change. An important aspect is monitoring how people (including scientists) impact on the environment and minimising such effects.
Dr Sharon Robinson joined the University of Wollongong's Biological Sciences Department in 1996 after four years at the Australian National University's Research School of Biological Sciences.
Her Antarctic Diary Website is at: http://www.uow.edu.au/science/research/affrc/antdiary/anthome.html