Antarctic Sea-ice Ecology
Kerrie Swadling
My
desire to go to Antarctica began at an early age when an ex-ANARE came
to speak at my primary school. I have no memory of his name and I occasionally
wonder if it was someone I now know or have heard of over the years. Although
I maintained an interest in polar regions, for a while my studies took me to
much warmer climes, first to James Cook University in Townsville where I
majored in marine biology and eventually to Florida where my MSc research
focussed on the Gulf of Mexico. In between I did manage my first trip to
Antarctica, in October 1987, when I worked as a field assistant on a project
examining the daily vertical migration habits of zooplankton in a marine fjord
near Davis station. That whet my appetite for further polar work and near the
end of my three years in Florida I arranged to come to Hobart to undertake a
PhD studying the overwintering biology of sea-ice related organisms near
Davis. After submitting my thesis I went back to North America for two years,
this time as a post-doc at Laval University in Québec City. I was fortunate
enough to do my field work near a remote Inuit village on the eastern shore of
Hudson Bay. For the last 4 years I have been working back in Hobart and I am
now involved with two ARC Discovery projects that focus on Antarctic biology.
My Antarctic research covers two main areas. The first involves the study of
sea-ice related organisms, particularly their biogeography, biochemistry and
ecology. I am interested in learning how the grazing behaviour of small
crustaceans that live in or near the sea-ice affects the mat of algae that
grows on the bottom of the ice. This algal mat is of fundamental importance to
the Antarctic marine ecosystem as it provides food for herbivores, firstly,
during the winter when algae in the water column are absent and, secondly,
during the spring when it sloughs off, sinks and feeds the juvenile stages of
bottom-dwelling organisms such as sea urchins, sea cucumbers and starfish. If,
as has been suggested, the southern ocean sea-ice declines by 50% by the end
of this century, it will have profound effects on the organisms that rely on
this habitat.
My second area of interest takes a longer term view and uses the remains of invertebrates found in sediments of Antarctic lakes to infer changes in the environment since the last glaciation. Well-preserved remains found in the sediments include the exoskeletons of copepods and cladocerans, rotifer loricas, foraminiferan tests, faecal pellets of copepods and eggs of rotifers, copepods, cladocerans and tardigrades. Relationships between the abundance of faunal remains in freshwater lakes and climatic conditions are being investigated, with the aim of understanding the effect of climate on lake ecology.
As the mother of two-year-old twins I have made the decision not to go south for a while. I would enjoy another trip but I don’t feel a burning need to go at present. Luckily I have been able to find enthusiastic people to participate in the field components of my work. Sampling and processing sea-ice for my work is not especially difficult and has been handled by some excellent young expeditioners. I do the detailed analyses and interpretation of the data in Hobart. I’ve also found that introducing Honours and postgraduate students to the joys and rigours of Antarctic work has become important to me.
I enjoy Antarctic work immensely and feel privileged to have spent quite a lot of time there. In some ways it is the non-scientific aspects of my time in Antarctica that have stayed most prominently in my mind — a 40 hour non-stop drive across the Plateau to Law Base, flying in helicopters between ice bergs and over sea-ice, watching penguins porpoising through the water, a full moon in a purple sky in winter, clear black ice on a freshwater lake, a September wedding, watching petrels coming to roost while the sun sets, excellent food at the Chinese Base Zhong Shan, late nights in the field when the sun is low in the sky……the list goes on!