Editorial: Polar and Alpine Microbiology-Earth's cryobiosphere.

Abstract

Microorganisms, representing all three domains of life, have successfully colonised Earth's cold environments that span from the Arctic to the Antarctic, from high mountain-range environments to the deep ocean, and include permafrost soils, marine sediments, and sea and glacial ice. Most of the Earth's biosphere is characterised by low temperatures (<5°C), and there is thus considerable interest in understanding the activities and adaptations of the microorganisms, as well as the ecological interactions of microbial communities active in these habitats. High altitude and high latitude regions on Earth are experiencing rapid changes in climate, with impacts on microbial activities and biogeochemical cycles. Clearly, knowledge of the distribution, biodiversity and functional roles of microorganisms inhabiting polar and alpine environments is essential to our understanding of ecosystem processes in a changing climate. Polar and alpine (high latitude and high altitude) regions, as with rest of our globe, share high genetic and functional diversity of prokaryotes (archaea, bacteria) and eukaryotes (microalgae and microfungi), as well as their viruses. Microbes are present in wide diversity and abundance and in all types of polar and alpine habitats (atmosphere, ice, snow, soils, permafrost, freshwater, marine). Due to their evolutionary antiquity, prokaryotic and also eukaryotic microbes are widely adapted to extremes. In high altitude and high latitude ecology, the central importance is low temperature (lack of solar radiation and/or its diurnal extremes) together with related environmental factors. The seasonal and diurnal variations of temperature create a series of water gradients ranging from solid to aquatic to vapour. These patterns differ in periodicity, amplitude, synchronicity and regularity. However, there is no generally accepted value for the lower temperature limit for life on the Earth (or potentially other planets or moons). Psychrophilic microbes have evolved a range of adaptations of all cellular constituents to counteract the potentially deleterious effects of … [↵][1]*E-mail: haggblom{at}sebs.rutgers.edu [1]: #xref-corresp-1-1