The concentrations and chemical forms of elements in natural waters determine their availability and toxicity to aquatic organisms.  Conversely, microorganisms influence the chemistry of aquatic systems by mediating oxidation reduction reactions, precipitating or dissolving minerals, releasing complexing agents, and absorbing or taking up chemical species.  The main focus of the Morel Research Group is the interactions between aquatic microorganisms and their chemical milieu with the goal of understanding the biogeochemical cycles of elements, particularly trace elements, and their ecological consequences at the local or global scale.