The development and function of subarctic alpine soil surface biological communities

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Due to their ubiquitous distribution and unique physiology, establishment of biological soil crust (BSC) communities and corresponding initiation of key ecosystem functions is a common early successional process. In alpine and arctic environments, BSCs are often a dominant vegetation unit, making these ecosystems a uniquely powerful model for examining the role of BSCs in terrestrial ecosystem development. My long-term goal is to identify mechanisms at the BSC-soil surface interface that drive nutrient cycling processes in arctic and alpine environments. BSCs are located at the soil-atmosphere interface where their developmental trajectories are driven by both microclimate and soil physicochemical factors. As these soil surface assemblages establish, they in turn modulate their environment through the initiation of key ecosystem functions at biogeochemical interfaces between BSCs and below-crust soils. Over the next 5 years my short-term goal is to link the realized niches of key BSC components with the initiation and modulation of nutrient cycling processes at the BSC-soil interface. My specific objectives are to: 1) develop successional models of BSC communities based upon the realized niche of primary macro and micro BSC phyla; 2) examine the development and function of BSC assemblages in relation to soil physical, chemical and microbial properties; and 3) relate BSC development to ecosystem-level nutrient cycling driven by BSC and below-crust soil microbial communities.