This research will conduct a large-scale community genomics analysis of fungi in the Arctic to provide insights into the diversity, metabolism, and seasonal dynamics of cold-adapted fungi. Fungi survive, reproduce, and carry out diverse biogeochemical transformations in arctic soils that are extremely cold, often dry, and mostly snow covered. Clearly, these fungi are adapted to extremes of cold and dark. Yet our knowledge of the identities and activities of these cold-adapted fungi is negligible. The goal of this work is to better understand fungal adaptation to cold, and will accomplish this by determining which species occur in the coldest climates, and which species are metabolically active at the coldest temperatures. While focused on adaptation, the project will also inform ecosystem ecology. Polar regions provide significant ecosystem services to society, including climate regulation. The ongoing changes in polar regions, which are often more rapid and of larger magnitude than in lower latitudes, are having uncertain effects on ecosystem services, particularly positive and negative feedbacks to global warming. Two key, interrelated uncertainties are 1) how vegetation patterns will change, and how these changes will feed back to climate, and 2) how soil carbon pools will change with changing patterns of permafrost, soil temperatures and vegetation cover. Mycorrhizal fungi strongly influence plant growth and community structure through their roles as ubiquitous symbionts of arctic plants. Decomposer fungi strongly influence rates and patterns of respiratory carbon release to the atmosphere, as well as mineralization and immobilization of the limiting nutrients nitrogen and phosphorus. Hence, soil-dwelling fungi are central players in both vegetation change and carbon dynamics, and therefore, uncertainties about the roles of fungi in polar ecosystem contribute to overall uncertainties about climate change and the future of polar regions. The three specific objectives in the research proposed are to: (1) reveal which fungal species are most adapted to extreme arctic environmental conditions by characterizing the changes in fungal communities along three latitudinal gradients (NAAT, Eurasia, Spitsbergen) using high-throughput, DNA-based clone-library sequencing; (2) test whether predicted changes in climate will select for more southerly or northerly fungal communities using reciprocal soil warming and cooling experiments and clone-library sequencing at the Toolik Lake and Bonanza Creek Long Term Ecological Research (LTER) sites; and (3) characterize the components of the fungal communities that are metabolically active in both summer and winter using a newly developed RNA-based library sequencing method. By revealing which species and guilds of fungi are most active in different habitats, in different seasons, and under different temperature regimes, the work will unveil novel insights into processes underling winter respiration and nutrient cycling in the Arctic. The study is pan-Arctic and international, both in geographic extent and in the collaborating consortium of US, Russian, and UK scientists. At the local level it will educate elementary school students about fungi and their ecology, and will support graduate education and scientific exchange among multiple countries.
