Methylmercury (MeHg) strongly bioaccumulates in aquatic food webs resulting in exposure to humans and wildlife through consumption of fish. Production of MeHg is promoted by anaerobic conditions and the supply of inorganic Hg (Hg2+), sulfate (SO42−), and labile organic carbon. The anaerobic sediments of stratified lakes are particularly active zones for methylation of Hg2+ and [...]