Alpine and arctic soil microbial communities

Abstract

Cold environments, where average daily air temperatures are below 5 °C throughout the year, are widespread in the terrestrial biosphere (Zakhia et al. 2008). These ecosystems are common in high mountain ranges, the high Arctic and Antarctica. In these areas, cold temperatures are often accompanied by freeze-thaw cycles, seasonally high solar radiation exposure, low nutrient supply, limited water availability, and high salinity. As a result of these conditions, such environments are mostly devoid of higher plants and are instead dominated by microbial communities. These areas have been referred to as the subnival zone, cold deserts, the allobiosphere, or the aeolian zone among other names (Bahl et al. 2011; Edwards 1988; King et al. 2008; Mayilraj et al. 2005; Swan 1992). Due to the absence of plants and large animals, comprehensive studies of the diversity of these ecosystems have been limited. However, recent advances in molecular techniques have allowed for more extensive study of the microorganisms that are abundant in these seemingly barren areas. High mountain cold desert areas are also receiving recent attention because they are in watersheds that are the source of water (from snow and ice melt) for a large proportion of the world's population, especially in areas downstream from the Andes, Rockies, and Himalayan Ranges. For example, the Himalayan-Karakorum-Hindu Kush Mountain complex provides water for approximately 1.3 billion people (Hua 2009). In addition, the global extent of cold, plant-free ecosystems is presently expanding rapidly as a result of glacier and ice cap melting due to global warming (Bradley et al. 2006; Byers 2007; Racoviteanu et al. 2008).