Community-Specific Biogeochemical Responses to Atmospheric Nitrogen Deposition in Subalpine Ecosystems
Project ID: P14AC01577
Federal Agency: National Park Service
Partner Institution: Washington State University
Fiscal Year: 2014
Initial Funding: $5,781
Total Funding: $5,781
Project Type: Research
Project Disciplines: Biological
National Park: Mount Rainier National Park
Principal Investigator: Evans, R. David
Agreement Technical Representative: Whiteaker, Lou
Abstract: Elevated anthropogenic nitrogen (N) emissions are causing higher rates of atmospheric N deposition (Ndep) that may saturate Cascade ecosystems with reactive N. Simultaneously, increasing global temperatures and altered circulation patterns generated by climate change are expected to strongly impact snow regimes in the Cascade Range, causing reduced snowpack, earlier snowmelt dates, and higher proportions of rain precipitation. Concern over the impacts of Ndep to sensitive, high-elevation ecosystems has prompted calls for
research into its interaction with climate change and the effects of Ndep on ecosystem services. This is a collaborative project between the National Park Service and Washington State University to improve understanding of community-specific impacts of elevated Ndep on biogeochemical processes, and the capacity of the lush-herbaceous, heathshrub, and wet sedge vegetation communities at Mt. Rainier National Park to absorb N during snowmelt. Preliminary (DayCent) biogeochemical model simulations have indicated that elevated Ndep increases soil N leaching rates, N2O emissions, microbial immobilization, and plant N uptake, with the greatest biogeochemical activity occurring during snowmelt. Project objectives include determining the amount, N form, and potential sources of snowpack Ndep and how the fate of snowpack Ndep is partitioned between inorganic N leaching, soil N2O emissions, microbial immobilization, and plant N storage in each subalpine vegetation community. This project will also determine how the snowpack Ndep rates change with elevated Ndep rates to determine potential thresholds for terrestrial ecosystem N saturation and loss processes. Ultimately, this study will provide insight to land managers and the public on the fate of N emissions, how Ndep affects ecosystem services in wilderness areas, and how climate change may affect ecosystem responses to Ndep.
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