title: Challenges in quantifying biosphere-atmosphere exchange of nitrogen species.
abstract: Recent research in nitrogen exchange with the atmosphere has separated research communities according to N form. The integrated perspective needed to quantify the net effect of N on greenhouse-gas balance is being addressed by the NitroEurope Integrated Project (NEU). Recent advances have depended on improved methodologies, while ongoing challenges include gas-aerosol interactions, organic nitrogen and N(2) fluxes. The NEU strategy applies a 3-tier Flux Network together with a Manipulation Network of global-change experiments, linked by common protocols to facilitate model application. Substantial progress has been made in modelling N fluxes, especially for N(2)O, NO and bi-directional NH(3) exchange. Landscape analysis represents an emerging challenge to address the spatial interactions between farms, fields, ecosystems, catchments and air dispersion/deposition. European up-scaling of N fluxes is highly uncertain and a key priority is for better data on agricultural practices. Finally, attention is needed to develop N flux verification procedures to assess compliance with international protocols.
authors.affiliation: Centre for Ecology and Hydrology, Edinburgh Research Station, Bush Estate, Penicuik, EH26 0QB, UK. ms@ceh.ac.uk
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mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000737:chemistry*; D001272:Atmosphere; D017753:Ecosystem; D004784:Environmental Monitoring / Q000379:methods; D005060:Europe; D017752:Greenhouse Effect; D008956:Models, Chemical; D017672:Nitrogen Compounds / Q000032:analysis / Q000737:chemistry*
chemical_list: D000393:Air Pollutants; D017672:Nitrogen Compounds