title: Differential exposure of alpine ospreys to mercury: melting glaciers, hydrology or deposition patterns?
abstract: Mercury (Hg) is a global contaminant impacting even remote environments. In alpine watersheds, glacial meltwater is a source of Hg, which accumulated in glaciers during the 1960-1980 cooling cycle. The considerable variation observed for Hg exposure of alpine animals in proximal watersheds could result from differences among those watersheds in Hg loading from glacial meltwater. Alternatively, variation may be the result of hydrology, atmospheric Hg deposition patterns, or food web characteristics. To examine those possibilities, we measured Hg in ospreys (Pandion haliaetus), apex predators in 15 watersheds in western Canada. Mercury levels in feathers of nestlings increased with increasing modeled atmospheric deposition rates and decreased with lake size. In eggs mercury decreased with δ(13)C, an indicator of food web structure, and with pH and elevation. Thus, Hg levels in chicks were strongly associated with local patterns relevant when the chicks were growing (e.g. the period post-snow melt: Hg deposition, lake size) while Hg levels in eggs were weakly associated with local patterns relevant during the snow melt (elevation, δ(13)C), with the remainder of the Hg variation in eggs determined by other factors such as possible Hg accumulation by the adult elsewhere. Modeled atmospheric deposition from prevailing upwind locations including Asia, followed by runoff into small lakes, were related to Hg patterns in osprey, with little apparent role for recent melting of glaciers. Our study highlights the importance of physical patterns to the environmental chemistry of top predators.
authors.affiliation: Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada R3T 2N2.
authors.forename: Mélanie F
authors.initials: MF
authors.lastname: Guigueno
authors.affiliation: Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada R3T 2N2.
authors.forename: Kyle H
authors.initials: KH
authors.lastname: Elliott
authors.affiliation: Department of Biological Sciences, University of Manitoba, Winnipeg, MB, Canada R3T 2N2.
authors.forename: Joshua
authors.initials: J
authors.lastname: Levac
authors.affiliation: Canadian Wildlife Service, Environment Canada, Saskatoon, SK, Canada, S7N 0X4.
authors.forename: Mark
authors.initials: M
authors.lastname: Wayland
authors.affiliation: Science & Technology Branch, Environment Canada, Delta, BC, Canada V4K 3N2. Electronic address: John.elliott@ec.gc.ca.
authors.forename: John E
authors.initials: JE
authors.lastname: Elliott
mesh_terms: D000397:Air Pollution / Q000706:statistics & numerical data; D000818:Animals; D001208:Asia; D001272:Atmosphere / Q000737:chemistry; D002170:Canada; D004781:Environmental Exposure / Q000032:analysis* / Q000706:statistics & numerical data; D046093:Falconiformes / Q000378:metabolism*; D005241:Feathers / Q000737:chemistry; D005260:Female; D020387:Food Chain; D005615:Freezing; D046448:Ice Cover / Q000737:chemistry; D060106:Lakes / Q000737:chemistry; D008628:Mercury / Q000032:analysis* / Q000378:metabolism; D008956:Models, Chemical; D010063:Ovum / Q000378:metabolism; D012914:Snow / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000378:metabolism
chemical_list: D014874:Water Pollutants, Chemical; D008628:Mercury