title: Throughfall and bulk deposition of dissolved organic nitrogen to holm oak forests in the Iberian Peninsula: Flux estimation and identification of potential sources.
abstract: Deposition of dissolved organic nitrogen (DON) in both bulk precipitation (BD) and canopy throughfall (TF) has been measured for the first time in the western Mediterranean. The study was carried out over a year from 2012 to 2013 at four evergreen holm oak forests located in the Iberian Peninsula: two sites in the Province of Barcelona (Northeastern Spain), one in the Province of Madrid (central Spain) and the fourth in the Province of Navarra (Northern Spain). In BD the annual volume weighted mean (VWM) concentration of DON ranged from 0.25 mg l(-1) in Madrid to 1.14 mg l(-1) in Navarra, whereas in TF it ranged from 0.93 mg l(-1) in Barcelona to 1.98 mg l(-1) in Madrid. The contribution of DON to total nitrogen deposition varied from 34% to 56% in BD in Barcelona and Navarra respectively, and from 38% in Barcelona to 72% in Madrid in TF. Agricultural activities and pollutants generated in metropolitan areas were identified as potential anthropogenic sources of DON at the study sites. Moreover, canopy uptake of DON in Navarra was found in spring and autumn, showing that organic nitrogen may be a supplementary nutrient for Mediterranean forests, assuming that a portion of the nitrogen taken up is assimilated during biologically active periods.
authors.affiliation: LICA, Department of Chemistry and Soil Science, Universidad de Navarra, Irunlarrea 1, 31008 Pamplona, Spain.
authors.forename: S
authors.initials: S
authors.lastname: Izquieta-Rojano
authors.affiliation: Ecotoxicology of Air Pollution, CIEMAT, Av. Complutense 40, 28040 Madrid, Spain.
authors.forename: H
authors.initials: H
authors.lastname: García-Gomez
authors.affiliation: CREAF, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors.forename: L
authors.initials: L
authors.lastname: Aguillaume
authors.affiliation: LICA, Department of Chemistry and Soil Science, Universidad de Navarra, Irunlarrea 1, 31008 Pamplona, Spain. Electronic address: chusmi@unav.es.
authors.forename: J M
authors.initials: JM
authors.lastname: Santamaría
authors.affiliation: Centre for Ecology & Hydrology (CEH), Edinburgh, EH26 0QB, UK.
authors.forename: Y S
authors.initials: YS
authors.lastname: Tang
authors.affiliation: LICA, Department of Chemistry and Soil Science, Universidad de Navarra, Irunlarrea 1, 31008 Pamplona, Spain.
authors.forename: C
authors.initials: C
authors.lastname: Santamaría
authors.affiliation: Ecotoxicology of Air Pollution, CIEMAT, Av. Complutense 40, 28040 Madrid, Spain.
authors.forename: F
authors.initials: F
authors.lastname: Valiño
authors.affiliation: LICA, Department of Chemistry and Soil Science, Universidad de Navarra, Irunlarrea 1, 31008 Pamplona, Spain.
authors.forename: E
authors.initials: E
authors.lastname: Lasheras
authors.affiliation: Ecotoxicology of Air Pollution, CIEMAT, Av. Complutense 40, 28040 Madrid, Spain.
authors.forename: R
authors.initials: R
authors.lastname: Alonso
authors.affiliation: CREAF, Universitat Autònoma de Barcelona, 08193 Bellaterra, Spain.
authors.forename: A
authors.initials: A
authors.lastname: Àvila
authors.affiliation: Centre for Ecology & Hydrology (CEH), Edinburgh, EH26 0QB, UK.
authors.forename: J N
authors.initials: JN
authors.lastname: Cape
authors.affiliation: LICA, Department of Chemistry and Soil Science, Universidad de Navarra, Irunlarrea 1, 31008 Pamplona, Spain.
authors.forename: D
authors.initials: D
authors.lastname: Elustondo
mesh_terms: D000383:Agriculture; D017753:Ecosystem; D004784:Environmental Monitoring; D004785:Environmental Pollutants / Q000032:analysis* / Q000737:chemistry; D065928:Forests; D009584:Nitrogen / Q000032:analysis* / Q000737:chemistry; D029963:Quercus; D012621:Seasons; D013030:Spain; D014197:Trees
chemical_list: D004785:Environmental Pollutants; D009584:Nitrogen
keywords: Anthropogenic nitrogen; Bulk deposition; Canopy throughfall; Dissolved organic nitrogen; Mediterranean ecosystems