title: Atmospheric deposition inputs and effects on lichen chemistry and indicator species in the Columbia River Gorge, USA.
abstract: Topographic and meteorological conditions make the Columbia River Gorge (CRG) an 'exhaust pipe' for air pollutants generated by the Portland-Vancouver metropolis and Columbia Basin. We sampled fog, bulk precipitation, throughfall, airborne particulates, lichen thalli, and nitrophytic lichen distribution. Throughfall N and S deposition were high, 11.5-25.4 and 3.4-6.7 kg ha(-1) over 4.5 months at all 9 and 4/9 sites, respectively. Deposition and lichen thallus N were highest at eastern- and western-most sites, implicating both agricultural and urban sources. Fog and precipitation pH were frequently as low as 3.7-5.0. Peak NO(x), NH(3), and SO(2) concentrations in the eastern CRG were low, suggesting enhanced N and S inputs were largely from particulate deposition. Lichens indicating nitrogen-enriched environments were abundant and lichen N and S concentrations were 2x higher in the CRG than surrounding national forests. The atmospheric deposition levels detected likely threaten Gorge ecosystems and cultural resources.
authors.affiliation: USDA Forest Service, Pacific Southwest Research Station, 4955 Canyon Crest Drive, Riverside, CA 92507, USA. mfenn@fs.fed.us <mfenn@fs.fed.us>
authors.forename: M E
authors.initials: ME
authors.lastname: Fenn
authors.forename: L
authors.initials: L
authors.lastname: Geiser
authors.forename: R
authors.initials: R
authors.lastname: Bachman
authors.forename: T J
authors.initials: TJ
authors.lastname: Blubaugh
authors.forename: A
authors.initials: A
authors.lastname: Bytnerowicz
mesh_terms: D000393:Air Pollutants / Q000032:analysis / Q000633:toxicity*; D002947:Cities; D017753:Ecosystem; D004784:Environmental Monitoring / Q000295:instrumentation / Q000379:methods*; D008011:Lichens / Q000737:chemistry*; D008685:Meteorological Concepts; D009584:Nitrogen / Q000032:analysis / Q000633:toxicity*; D009922:Oregon; D052638:Particulate Matter / Q000032:analysis / Q000633:toxicity; D045483:Rivers; D013455:Sulfur / Q000032:analysis / Q000633:toxicity*; D014861:Washington
chemical_list: D000393:Air Pollutants; D052638:Particulate Matter; D013455:Sulfur; D009584:Nitrogen