Hg2+ incorporation in Andean Patagonian ultraoligotrophic lakes: insights into the role of pelagic protists

Abstract. In ultraoligotrophic lakes of Andean Patagonia, microbial assemblages at the base pelagic food webs bear high THg concentrations compared to planktonic consumers. this study, we evaluate experimentally passive and active (trophic) uptake Hg2+ using 197Hg2+ trace Hg incorporation in picoplankton (autotrophic heterotrophic bacteria), photoautotrophic phytoflagellate, Gymnodinium paradoxum, mixotrophic ciliates, Stentor araucanus Ophrydium naumanni. The studied protists were found incorporate substantial amounts dissolved Hg2+; however, their potential for transference higher trophic levels depends on degree internalization (cytoplasmatic Hg), which varied widely among species.