Oligotrophy as a major driver of mercury bioaccumulation in medium-to high-trophic level consumers: A marine ecosystem-comparative study
|Author(s)||Chouvelon Tiphaine1, Cresson Pierre2, 3, Bouchoucha Marc2, Brach-Papa Christophe1, 2, Bustamante Paco4, Crochet Sylvette1, Marco-Miralles Francoise2, Thomas Bastien1, Knoery Joel1|
|Affiliation(s)||1 : IFREMER, Lab Biogeochim Contaminants Metall, Unite Biogeochim & Ecotoxicol, Rue Ile Yeu,BP 21105, F-44311 Nantes 03, France.
2 : IFREMER, Lab Environm Ressources Provence Azur Corse, Unite Littoral, CS 20330, F-83507 La Seyne Sur Mer, France.
3 : IFREMER, Lab Ressources Halieut Boulogne, Unite Halieut Manche Mer Nord, 150 Quai Gambetta, F-62200 Boulogne Sur Mer, France.
4 : Univ La Rochelle, CNRS, Littoral Environm & Soc LIENSs, UMR 7266, 2 Rue Olympe de Gouges, F-17042 La Rochelle 01, France.
|Source||Environmental Pollution (0269-7491) (Elsevier Sci Ltd), 2018-02 , Vol. 233 , P. 844-854|
|WOS© Times Cited||3|
|Keyword(s)||Biomagnifying metal, Bioaccumulation, Trophic status, Ecosystem productivity, Temperate systems|
Mercury (Hg) is a global contaminant of environmental concern. Numerous factors influencing its bioaccumulation in marine organisms have already been described at both individual and species levels (e.g., size or age, habitat, trophic level). However, few studies have compared the trophic characteristics of ecosystems to explain underlying mechanisms of differences in Hg bioaccumulation and biomagnification among food webs and systems. The present study aimed at investigating the potential primary role of the trophic status of systems on Hg bioaccumulation and biomagnification in temperate marine food webs, as shown by their medium-to high-trophic level consumers. It used data from samples collected at the shelf-edge (i.e. offshore organisms) in two contrasted ecosystems: the Bay of Biscay in the North-East Atlantic Ocean and the Gulf of Lion in the North-West Mediterranean Sea. Seven species including crustaceans, sharks and teleost fish, previously analysed for their total mercury (T-Hg) concentrations and their stable carbon and nitrogen isotope compositions, were considered for a meta-analysis. In addition, methylated mercury forms (or methyl-mercury, Me-Hg) were analysed. Mediterranean organisms presented systematically lower sizes than Atlantic ones, and lower δ13C and δ15N values, the latter values especially highlighting the more oligotrophic character of Mediterranean waters. Mediterranean individuals also showed significantly higher T-Hg and Me-Hg concentrations. Conversely, Me-Hg/T-Hg ratios were higher than 85% for all species, and quite similar between systems. Finally, the biomagnification power of Hg was different between systems when considering T-Hg, but not when considering Me-Hg, and was not different between the Hg forms within a given system. Overall, the different parameters showed the crucial role of the low primary productivity and its effects rippling through the compared ecosystems in the higher Hg bioaccumulation seen in organisms from oligotrophic Mediterranean waters.