Study of the spatial and temporal trends of mercury in the Arctic : use of teeth and hair of the top predators as biomonitoring tissues

• Main Author: Aubail, Aurore
• Other Authors: LIttoral ENvironnement et Sociétés - UMR 7266 (LIENSs), Institut national des sciences de l'Univers (INSU - CNRS)-La Rochelle Université (ULR)-Centre National de la Recherche Scientifique (CNRS), Université de La Rochelle, Vincent Ridoux
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2010
• Subjects: Mercury; Stable isotopes of nitrogen and carbon; Spatial and temporal trends; Hard tissues; Top-predators; Climate change; Arctic; Mercure; Isotopes stables d’azote et de carbone; Tendances spatiales et temporelles; Tissus durs; Prédateurs supérieurs; Réchauffement climatique; Arctique; [SDV.SA]Life Sciences [q-bio]/Agricultural sciences; Svalbard; Greenland; Phoques; Arctique*; Phoca hispida; Ursus maritimus
• Online Access: https://theses.hal.science/tel-00583122; https://theses.hal.science/tel-00583122/document; https://theses.hal.science/tel-00583122/file/THESE15jan2010.pdf

The spatial and temporal trends of mercury in the Arctic have been studied through the analysis of this metal in hard tissues, i.e. teeth and hair, in ringed seals (Phoca hispida) and polar bears (Ursus maritimus). Sex had no influence on the mercury concentrations while age was a significant factor.Two distinct spatial trends were observed in the tissues of these two species: a first gradient of augmentation from the East to the West of the Arctic, i.e. from Svalbard towards Greenland and the Canadian Arctic, and a second one, from the South to the North of the Canadian Arctic, resulting probably from a combination of the global mineralogy in the Arctic with biotic and abiotic factors.An increasing trend in mercury concentrations has been detected globally between the preindustrial period and the end of the 20th century. However, the temporal trends detected in the second part of the 20th century revealed an increase in the West Arctic while a decrease was observed in the East Arctic. This difference seems to be due to a distinct input of the atmospheric air masses to the two regions. Besides, a climatic variability could contribute to the variations observed these last decennials by influencing the habitat and the feeding habits of the marine predators. Thus, the determination of the stable isotopes seems to be essential to combine to the study of the mercury trends.Finally, this study has showed the importance of hair as a non-invasive and relevant biomonitoring tissue on a regular or annual sampling base, while the use of the teeth seems to be more adequate for reconstructing long-term trends of mercury. Les tendances spatiales et temporelles du mercure en Arctique ont été étudiées au travers de l’analyse de ce métal dans les tissus durs, i.e. dents et poils, des phoques annelés (Phoca hispida) et des ours polaires (Ursus maritimus). Aucune influence du sexe sur les concentrations n’a été détectée dans les tissus de ces deux espèces alors que l’âge est apparu comme un facteur d’influence important.Deux ...