ETBC: A new tool for assessing nitrogen saturation status in forests- Mass-independent D17O of nitrate

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ETBC: A new tool for assessing nitrogen saturation status in forests? Mass-independent oxygen isotopes of nitrateEmily M. Elliott, Principal InvestigatorUniversity of PittsburghPROJECT ABSTRACTAs U.S. forests continue to age, nitrate leaching from forests could become an increasingly important contributor to surface water quality impairment. This project establishes the use of a mass-independent oxygen isotope tracer of atmospheric nitrate as an empirical tool for quantifying export of atmospheric nitrate from forested watersheds and for assessing the nitrogen saturation status of watersheds lacking long-term water quality data. The objectives of research include the following: 1) development of a new empirical tool for accurately quantifying atmospheric nitrate export from watersheds and associated N saturation status; 2) an intra-watershed assessment of spatial heterogeneity of nitrate sources in soil water leachate in a N saturated system; and 3) a characterization of high resolution temporal dynamics of nitrate sources to streamwater during episodic acidification stormflows. This research is expected to provide an unparalleled ability to assess the impacts of chronic N deposition at a much higher spatial resolution than previously possible, transforming our understanding of the interactions between atmospheric deposition, ecosystem health and water quality. Additionally, the project will generate new insight into how forest management strategies can influence atmospheric N export with important implications for managing water quality in sensitive systems and improve our process-level understanding of spatial and temporal variations in atmospheric N export with important implications for the ecological and hydrological modeling communities.