The primary focus of the research performed in Professor Gaillard’s group is to understand the biogeochemical processes that affect the fate of metals in aquatic systems. A special emphasis is to elucidate how the chemical speciation of metals controls their biouptake/bioavailability focusing on microbial species, since microorganisms constitute the foundation of any ecological system. The group is conducting field studies, laboratory experiments, and using modeling approaches based on advanced analytical, microscopic, and spectroscopic methods. Recent activities have been centered on the chemical fate of As, Ni, and Hg in aquatic environments as well as on the environmental impacts of nano-structured materials commonly used.