title: Species-specific isotope tracers to study the accumulation and biotransformation of mixtures of inorganic and methyl mercury by the microalga Chlamydomonas reinhardtii.
abstract: The present study demonstrates that species-specific isotope tracing is an useful tool to precisely measure Hg accumulation and transformations capabilities of living organisms at concentrations naturally encountered in the environment. To that end, a phytoplanktonic green alga Chlamydomonas reinhardtii Dangeard (Chlamydomonadales, Chlorophyceae) was exposed to mixtures of (199)-isotopically enriched inorganic mercury ((199)IHg) and of (201)-isotopically enriched monomethylmercury ((201)CH3Hg) at a concentration range between less than 1 pM to 4 nM. Additionally, one exposure concentration of both mercury species was also studied separately to evaluate possible interactive effects. No difference in the intracellular contents was observed for algae exposed to (199)IHg and (201)CH3Hg alone or in their mixture, suggesting similar accumulation capacity for both species at the studied concentrations. Demethylation of (201)CH3Hg was observed at the highest exposure concentrations, whereas no methylation was detected.
authors.affiliation: University of Geneva, Earth and Environment Sciences, Institute F.-A. Forel, 10 route de Suisse, CP 416, CH-1290 Versoix, Switzerland. Electronic address: andrea.garcia@ebc.uu.se.
authors.forename: Andrea Garcia
authors.initials: AG
authors.lastname: Bravo
authors.affiliation: University of Geneva, Earth and Environment Sciences, Institute F.-A. Forel, 10 route de Suisse, CP 416, CH-1290 Versoix, Switzerland.
authors.forename: Séverine
authors.initials: S
authors.lastname: Le Faucheur
authors.affiliation: Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux, IPREM UMR 5254 CNRS - Université de Pau et des Pays de l'Adour, Hélioparc, 2, Avenue Pierre Angot, 64053 Pau Cedex, France.
authors.forename: Mathilde
authors.initials: M
authors.lastname: Monperrus
authors.affiliation: Laboratoire de Chimie Analytique Bio-Inorganique et Environnement, Institut des Sciences Analytiques et de Physico-chimie pour l'Environnement et les Matériaux, IPREM UMR 5254 CNRS - Université de Pau et des Pays de l'Adour, Hélioparc, 2, Avenue Pierre Angot, 64053 Pau Cedex, France.
authors.forename: David
authors.initials: D
authors.lastname: Amouroux
authors.affiliation: University of Geneva, Earth and Environment Sciences, Institute F.-A. Forel, 10 route de Suisse, CP 416, CH-1290 Versoix, Switzerland. Electronic address: vera.slaveykova@unige.ch.
authors.forename: Vera I
authors.initials: VI
authors.lastname: Slaveykova
mesh_terms: D001711:Biotransformation; D016825:Chlamydomonas reinhardtii / Q000378:metabolism*; D004784:Environmental Monitoring / Q000379:methods*; D007554:Isotopes / Q000378:metabolism; D008628:Mercury / Q000378:metabolism*; D008767:Methylmercury Compounds / Q000378:metabolism*; D013045:Species Specificity; D014874:Water Pollutants, Chemical / Q000378:metabolism*
chemical_list: D007554:Isotopes; D008767:Methylmercury Compounds; D014874:Water Pollutants, Chemical; C073972:dimethyl mercury; D008628:Mercury
keywords: Algae; Mercury; Methylmercury; Species-specific isotope tracers; Uptake