title: Fluxes of oxidised and reduced nitrogen above a mixed coniferous forest exposed to various nitrogen emission sources.
abstract: Concentrations of nitrogen gases (NH(3), NO(2), NO, HONO and HNO(3)) and particles (pNH(4) and pNO(3)) were measured over a mixed coniferous forest impacted by high nitrogen loads. Nitrogen dioxide (NO(2)) represented the main nitrogen form, followed by nitric oxide (NO) and ammonia (NH(3)). A combination of gradient method (NH(3) and NO(x)) and resistance modelling techniques (HNO(3), HONO, pNH(4) and pNO(3)) was used to calculate dry deposition of nitrogen compounds. Net flux of NH(3) amounted to -64 ng N m(-2) s(-1) over the measuring period. Net fluxes of NO(x) were upward (8.5 ng N m(-2) s(-1)) with highest emission in the morning. Fluxes of other gases or aerosols substantially contributed to dry deposition. Total nitrogen deposition was estimated at -48 kg N ha(-1) yr(-1) and consisted for almost 80% of NH(x). Comparison of throughfall nitrogen with total deposition suggested substantial uptake of reduced N (+/-15 kg N ha(-1) yr(-1)) within the canopy.
authors.affiliation: Research Institute for Nature and Forest, Gaverstraat 4, B-9500 Geraardsbergen, Belgium. johan.neirynck@inbo.be
authors.forename: J
authors.initials: J
authors.lastname: Neirynck
authors.forename: A S
authors.initials: AS
authors.lastname: Kowalski
authors.forename: A
authors.initials: A
authors.lastname: Carrara
authors.forename: G
authors.initials: G
authors.lastname: Genouw
authors.forename: P
authors.initials: P
authors.lastname: Berghmans
authors.forename: R
authors.initials: R
authors.lastname: Ceulemans
mesh_terms: D015258:Acid Rain; D000336:Aerosols; D000393:Air Pollutants / Q000032:analysis*; D000641:Ammonia / Q000032:analysis; D004784:Environmental Monitoring / Q000379:methods; D016468:Forestry; D008962:Models, Theoretical; D009426:Netherlands; D009566:Nitrates / Q000032:analysis; D017942:Nitric Acid / Q000032:analysis; D009569:Nitric Oxide / Q000032:analysis; D009584:Nitrogen / Q000032:analysis*; D009585:Nitrogen Dioxide / Q000032:analysis; D009608:Nitrous Acid / Q000032:analysis; D010084:Oxidation-Reduction; D052638:Particulate Matter; D041605:Pinus sylvestris
chemical_list: D015258:Acid Rain; D000336:Aerosols; D000393:Air Pollutants; D009566:Nitrates; D052638:Particulate Matter; D009569:Nitric Oxide; D017942:Nitric Acid; D000641:Ammonia; D009584:Nitrogen; D009585:Nitrogen Dioxide; D009608:Nitrous Acid