title: Mercury transfer from fish carcasses to scavengers in boreal lakes: the use of stable isotopes of mercury.
abstract: Scavengers play an important role in the flow of energy, matter and pollutants through food webs. For methylmercury (MeHg), which biomagnifies along food chains, the movement of this metal from fish carcasses to aquatic scavengers has never been demonstrated. We measured the transfer of MeHg from fish carcasses to scavenging leeches in two lakes and in the laboratory. The results of a field experiment indicated that leeches were attracted to fish carcasses and that their Hg concentrations increased by as much as a factor of 5 during the time that Hg-rich fish were available for consumption. Under controlled conditions, we exposed leeches to (202)Hg-labelled fish that had been marked in situ following a whole lake (202)Hg addition. Leeches rapidly accumulated Hg from carcasses, and within two weeks assumed the isotopic signature of the carcasses. Necrophagous invertebrates could therefore return Hg from fish carcasses to other trophic levels in lakes.
authors.affiliation: Institut National de la Recherche Scientifique (INRS) - Eau, Terre et Environnement, Université du Québec, C.P. 7500, Sainte-Foy, QC, Canada. saricajo@inrs-ete.uquebec.ca
authors.forename: José
authors.initials: J
authors.lastname: Sarica
authors.forename: Marc
authors.initials: M
authors.lastname: Amyot
authors.forename: Landis
authors.initials: L
authors.lastname: Hare
authors.forename: Paul
authors.initials: P
authors.lastname: Blanchfield
authors.forename: R A
authors.initials: RA
authors.lastname: Drew Bodaly
authors.forename: Holger
authors.initials: H
authors.lastname: Hintelmann
authors.forename: Marc
authors.initials: M
authors.lastname: Lucotte
mesh_terms: D000821:Animal Feed; D000818:Animals; D004784:Environmental Monitoring / Q000379:methods*; D005399:Fishes / Q000378:metabolism; D020387:Food Chain; D005618:Fresh Water; D007865:Leeches / Q000378:metabolism; D008628:Mercury / Q000032:analysis*; D008629:Mercury Isotopes / Q000032:analysis; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D008629:Mercury Isotopes; D014874:Water Pollutants, Chemical; D008628:Mercury