title: Regional variation in the chemical composition of winter snow pack and terricolous lichens in relation to sources of acid emissions in the Usa river basin, northeast European Russia.
abstract: The chemical composition of snow and terricolous lichens was determined along transects through the Subarctic towns of Vorkuta (130 km west-east), Inta (240 km south-north) and Usinsk (140 km, southwest-northeast) in the Usa river basin, northeast European Russia. Evidence of pollution gradients was found on two spatial scales. First, on the Inta transect, northward decreases in concentrations of N in the lichen Cladonia stellaris (from 0.57 mmol N g(-1) at 90 km south to 0.43 mmol N g(-1) at 130 km north of Inta) and winter deposition of non-sea salt sulphate (from 29.3 to 12.8 mol ha(-1) at 90 km south and 110 km north of Inta, respectively) were attributed to long range transport of N and S from lower latitudes. Second, increased ionic content (SO42-, Ca2+, K+) and pH of snow, and modified N concentration and the concentration ratios K+:Mg2+ and K+: (Mg2++Ca2+) in lichens (Cladonia arbuscula and Flavocetraria cucullata) within ca. 25-40 km of Vorkuta and Inta were largely attributed to local deposition of alkaline coal ash. Total sulphate concentrations in snow varied from ca. 5 micromol l(-1) at remote sites to ca. 19 micromol l(-1) near Vorkuta. Nitrate concentration in snow (typically ca. 9 micromol l(-1)) did not vary with proximity to perceived pollution sources.
authors.affiliation: School of Life and Environmental Sciences, University of Nottingham, UK.
authors.forename: T R
authors.initials: TR
authors.lastname: Walker
authors.forename: P D
authors.initials: PD
authors.lastname: Crittenden
authors.forename: S D
authors.initials: SD
authors.lastname: Young
mesh_terms: D015258:Acid Rain / Q000032:analysis*; D001110:Arctic Regions; D004784:Environmental Monitoring / Q000379:methods*; D006863:Hydrogen-Ion Concentration; D008011:Lichens / Q000737:chemistry*; D009584:Nitrogen / Q000032:analysis; D012426:Russia; D012914:Snow; D012989:Soil Pollutants / Q000032:analysis
chemical_list: D015258:Acid Rain; D012989:Soil Pollutants; D009584:Nitrogen