Loss and Retention of Nitrogen in an Artic Landscape: Key Pathways and Process Regulation

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The broad aim of this research is to improve understanding of how nitrogen (N) loss and retention processes affect long-term N accumulation and "N limitation" in terrestrial ecosystems. The specific aim is to determine the major pathways of N loss from Alaskan tundra ecosystems, the controls over those losses, and the importance of the losses for N accumulation and for interactions with the carbon (C) cycle. The field research will be based at Toolik Field Station, Alaska, and the research design is built around three core questions: What are the major forms and rates of N loss from different tundra ecosystem types? What are the major environmental and biological controls over these N losses? What are the impacts of N loss on overall N and C budgets of tundra ecosystems? The research design includes both field and laboratory experiments, and also the monitoring of N movement through soils and surface waters of a small watershed, Imnavait Creek. Simulation models will be used to construct N budgets at various timescales and to predict changes in N and C cycling in response to climate change and other disturbances.