Polar Microbiology: Recent Advances and Future Perspectives

Abstract

Most of the Earth’s biosphere is cold (85% is permanently exposed to temperatures below 5 °C), with 14% being polar. Polar regions are areas of the globe surrounding the poles. They are different in that the Arctic is a frozen ocean surrounded by continental landmasses and open oceans, whereas Antarctica is a frozen continent surrounded solely by oceans. The Arctic has numerous definitions; the most used defines it as the region north of the Arctic Circle (66.5° north latitude), including the Arctic Ocean and the islands and northern continental land areas from North America, Europe and Asia. According with the 1959 Antarctic Treaty, Antarctica is defined as the region south of 60° south latitude. Both polar regions are dominated by cold conditions and the presence of ice, snow, and water. Nonetheless, these environments are far from uniform and present a great variety of niches including different rocks, sediments, soil types, and melt-waters, as well as snow and ice that vary in terms of nutrient and water availability, salinity, and thermal regime. Even the apparently uniform environment of ice contains a network of liquid water veins (brine veins) that can transport soluble and insoluble particles and support life within it. Novel studies have demonstrated that active microbial respiration occurs within these ice structures and that there may have significant microbial variability within these ice-rich environments.

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