title: Factors affecting methylmercury biomagnification by a widespread aquatic invertebrate predator, the phantom midge larvae Chaoborus.
abstract: MeHg biomagnification by the phantom midge Chaoborus in relation to MeHg concentrations in their prey and its migratory behavior was investigated in two Canadian Precambrian Shield lakes. Three Chaoborus species with contrasted migratory behavior were collected in a fishless and a fish-inhabited lake. All species accumulated MeHg through their ontogenic development. In the lake inhabited by fish, all instars of Chaoborus punctipennis displayed a marked migratory behavior and were unable to biomagnify MeHg, whereas in the fishless lake, Chaoborus americanus and Chaoborus trivittatus biomagnified MeHg. Reduced biomagnification capacity of C. trivittatus, the coexisting species living with C. americanus, was also ascribed to a progressive vertical segregation with age. Growth dilution, amount and type of prey items or trophic position could not explain the different patterns of biomagnification. Our findings demonstrate that the most common invertebrate predator of temperate planktonic food webs can biomagnify mercury, contrarily to previous reports.
authors.affiliation: Groupe de recherche interuniversitaire en limnologie (GRIL), Département de sciences biologiques, Université de Montréal, C.P. 6128, Succursale Centre-Ville, Pavillon Marie-Victorin, Montréal, Québec, Canada H3C 3J7.
authors.forename: Anne-Hélène
authors.initials: AH
authors.lastname: Le Jeune
authors.forename: Floriane
authors.initials: F
authors.lastname: Bourdiol
authors.forename: Lama
authors.initials: L
authors.lastname: Aldamman
authors.forename: Tania
authors.initials: T
authors.lastname: Perron
authors.forename: Marc
authors.initials: M
authors.lastname: Amyot
authors.forename: Bernadette
authors.initials: B
authors.lastname: Pinel-Alloul
mesh_terms: D000818:Animals; D004175:Diptera / Q000378:metabolism*; D004784:Environmental Monitoring; D020387:Food Chain; D008767:Methylmercury Compounds / Q000032:analysis / Q000378:metabolism*; D014874:Water Pollutants, Chemical / Q000032:analysis / Q000378:metabolism*
chemical_list: D008767:Methylmercury Compounds; D014874:Water Pollutants, Chemical