The Molecular and Physiological Mechanisms of Microbial Survival in Antarctic Lakes

If these bacteria have invested in the evolution of antifreeze proteins they must also have developed suites of low temperatures enzymes which mediate routine cellular functions. One aspect of this project will concentrate on identifying such enzymes and quantifying their activity in different bacterial species, which will be identified using modern molecular techniques. Thus the outcome will be a picture of what enzymes occur, and which bacterial groups possess them.

Low temperature enzymes have many potential industrial uses and it is hoped that some of the enzymes identified may be developed by industry. The commercial application of some low temperature enzymes, e.g. lipases, are presently being trialled Our previous work in Vestfold Hills has shown that during the Antarctic winter many of the most successful and abundant protozoans maintain active populations, so that when the brief austral summer arrives 'they hit the deck running'.

In order to do this many of them possess extraordinary nutritional versatility. They are able to undertake photosynthesis like plants and eat bacteria. As day length and the light climate change in the annual cycle, such species switch from a dependence on photosynthesis in summer, to feeding on bacteria in winter.

We propose investigating this phenomenon, known as mixotrophy, in a number of the dominant species (Pyramimonas and Cryptomonas) in several of the saline lakes within the Vestfold Hills. This work will contribute to understanding how pristine Antarctic lake ecosystems function; information which is fundamental to monitoring changes induced by climate change. It has recently been reported that environmental warming alters food web structure and trophic interactions (Petchy et al., 1999).

These delicate ecosystems are likely to show rapid response to climatic perturbations, indeed long-term work in the Dry Valleys of Southern Victoria Land has demonstrated that Antarctic lakes are responding markedly to climate change. The download file contains an excel spreadsheet of data from Ace Lake and Highway Lake, as well as two word documents, one containing further data, and another containing details on the methods used in the data collection and analysis.

The fields in this dataset are: Date Depth Chlamydomonas Cryptophyte Heterotrophic bacteria Heterotrophic nanoflagellates Ciliate Mesodinium Paralabidocera Pyramimonas Daphniopsis Chlorophyll a