Extremophiles in antarctica: Life at low temperatures

Abstract

In this chapter we will explore the different adaptations of extremophiles to life in the extreme cold. We generally forget that the Earth is mostly cold and that most ecosystems are exposed to temperatures that are permanently below 5 °C. Such low mean temperatures mainly arise from the fact that ~70 % of the Earth’s surface is covered by oceans that have a constant temperature of 4-5 °C (below a depth of 1,000 m), irrespective of the latitude. The polar regions account for another 15 % of the surface, to which the glacier and alpine regions must also be added. Here, we will take an illustrated look in particular at the Antarctic environment, as it is by far the coldest environment on Earth - the lowest temperature on the surface of the Earth (-89.2 °C) was recorded at the Russian Vostok Station, at the centre of the East Antarctic ice sheet. Antarctica is a place where organisms are often subjected to combined stresses including desiccation, limited nutrient availability, high salinity, adverse solar radiation and low biochemical activity. The incredibly harsh environment of the Antarctic continent precludes life in most of its forms, and the microorganisms are therefore dominant.