Investigations on mercury transformations in seawater using isotopically enriched species
Résumé
The aim of this work was to developed field incubations of seawater using isotopically enriched inorg. mercury (199IHg) and monomethylmercury (201MMHg) to understand processes involved in mercury transformations. Expts. were carried out for different sites of the Mediterranean Sea, at coastal and open water stations as a contribution to the MERCYMS project in the framework of the EU ELOISE program. Water incubations were conducted under various controlled conditions (dark and light, filtered and unfiltered water) to assess the major biogeochem. pathways regulating mercury transformations. Biol. characteristics of the incubated samples were also monitored through phytoplankton and bacteria diversity. Isotopically enriched species were used as chem. tracers and have allowed the direct detn. of specific methylation and demethylation yields. This exptl. approach demonstrates that the use of isotopically labeled mercury species offers a unique potential to examine mercury transformation processes in seawater.