title: Mercury concentrations in landlocked Arctic char (Salvelinus alpinus) from the Canadian Arctic. Part I: insights from trophic relationships in 18 lakes.
abstract: Concentrations of mercury (Hg) have increased slowly in landlocked Arctic char over a 10- to 15-year period in the Arctic. Fluxes of Hg to sediments also show increases in most Arctic lakes. Correlation of Hg with trophic level (TL) was used to investigate and compare biomagnification of Hg in food webs from lakes in the Canadian Arctic sampled from 2002 to 2007. Concentrations of Hg (total Hg and methylmercury [MeHg]) in food webs were compared across longitudinal and latitudinal gradients in relation to delta(13)C and delta(15)N in periphyton, zooplankton, benthic invertebrates, and Arctic char of varying size-classes. Trophic magnification factors (TMFs) were calculated for the food web in each lake and related to available physical and chemical characteristics of the lakes. The relative content of MeHg increased with trophic level from 4.3 to 12.2% in periphyton, 41 to 79% in zooplankton, 59 to 72% in insects, and 74 to 100% in juvenile and adult char. The delta(13)C signatures of adult char indicated coupling with benthic invertebrates. Cannibalism among char lengthened the food chain. Biomagnification was confirmed in all 18 lakes, with TMFs ranging from 3.5 +/- 1.1 to 64.3 +/- 0.8. Results indicate that TMFs and food chain length (FCL) are key factors in explaining interlake variability in biomagnification of [Hg] among different lakes.
authors.affiliation: Department of Environmental Biology, University of Guelph, Guelph, Ontario, Canada. nikolaus.gantner@ec.gc.ca
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Gantner
authors.forename: Michael
authors.initials: M
authors.lastname: Power
authors.forename: Deborah
authors.initials: D
authors.lastname: Iqaluk
authors.forename: Markus
authors.initials: M
authors.lastname: Meili
authors.forename: Hans
authors.initials: H
authors.lastname: Borg
authors.forename: Marcus
authors.initials: M
authors.lastname: Sundbom
authors.forename: Keith R
authors.initials: KR
authors.lastname: Solomon
authors.forename: Greg
authors.initials: G
authors.lastname: Lawson
authors.forename: Derek C
authors.initials: DC
authors.lastname: Muir
mesh_terms: D000818:Animals; D001110:Arctic Regions; D002170:Canada; D004784:Environmental Monitoring; D020387:Food Chain; D005618:Fresh Water / Q000032:analysis*; D008628:Mercury / Q000032:analysis*; D008767:Methylmercury Compounds / Q000032:analysis; D014337:Trout / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D008767:Methylmercury Compounds; D014874:Water Pollutants, Chemical; D008628:Mercury