Composition and Bioavailability of Dissolved Organic Nitrogen in Atmospheric Deposition (EGB)

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9807621SeitzingerMarked changes in both terrestrial and aquatic ecosystems are occurring as a result of increased anthropogenic nitrogen (N) in atmospheric deposition. N deposition is predicted to increase over twofold in the next 20 years. To date, most studies of the magnitude, sources and effects of atmospherically deposited N have only considered inorganic-N. However, a considerable portion of N in rainwater is in the form of organic-N, and almost nothing is known of the chemical composition, sources or ecosystem effects of the bulk of that organic-N. The proposed studies will: (1) develop to characterize the chemical composition of dissolved organic nitrogen (DOM) in atmospheric deposition; (2) characterize the chemical compositon of DOM in atmospheric deposition at a relatively perturbed site in the Northeastern U.S. over an annual cycle; (3) determine how much of the total DOM in the rainwater in spring is biologically available to coastal plankton communities and provide insight into potential changes in plankton production and community composition; and (4) begin to characterize the chemical composition of the DOM compound classes that are bio-available and thus contributing to ecological changes in receiving ecosystems. The approach will provide a mass balance of total N (organic-N and inorganic-N) and of the various forms of organic N in precipitation. The chemical characterization studies will be integrated with ecological studies. This study will generate information needed to help understand the continental pathways of pollutant and natural N atmospheric compounds in the Northeastern U.S.. Moreover, by linking the bioavailability studies with precipitation N loading and composition, atmospherically processed N compounds will be related to sensitive ecosystems. The project will provide research opportunities for undergraduates to Rutgers University Douglass College. Integration of undergraduate students in this research program will provide the framework for students and researchers to explore together important linkages among human activities/land use, atmospheric geochemical processes, and biogeochemical processes in aquatic ecosystems.9807621SeitzingerMarked changes in both terrestrial and aquatic ecosystems are occurring as a result of increased anthropogenic nitrogen (N) in atmospheric deposition. N deposition is predicted to increase over twofold in the next 20 years. To date, most studies of the magnitude, sources and effects of atmospherically deposited N have only considered inorganic-N. However, a considerable portion of N in rainwater is in the form of organic-N, and almost nothing is known of the chemical composition, sources or ecosystem effects of the bulk of that organic-N. The proposed studies will: (1) develop to characterize the chemical composition of dissolved organic nitrogen (DOM) in atmospheric deposition; (2) characterize the chemical compositon of DOM in atmospheric deposition at a relatively perturbed site in the Northeastern U.S. over an annual cycle; (3) determine how much of the total DOM in the rainwater in spring is biologically available to coastal plankton communities and provide insight into potential changes in plankton production and community composition; and (4) begin to characterize the chemical composition of the DOM compound classes that are bio-available and thus contributing to ecological changes in receiving ecosystems. The approach will provide a mass balance of total N (organic-N and inorganic-N) and of the various forms of organic N in precipitation. The chemical characterization studies will be integrated with ecological studies. This study will generate information needed to help understand the continental pathways of pollutant and natural N atmospheric compounds in the Northeastern U.S.. Moreover, by linking the bioavailability studies with precipitation N loading and composition, atmospherically processed N compounds will be related to sensitive ecosystems. The project will provide research opportunities for undergraduates to Rutgers University Douglass College. Integration of undergraduate students in this research program will provide the framework for students and researchers to explore together important linkages among human activities/land use, atmospheric geochemical processes, and biogeochemical processes in aquatic ecosystems.