Mercury (Marine)

Mercury is a toxic heavy metal that cycles through the ocean in inorganic and organic forms and is the only metal with its own global treaty, the Minamata Convention on Mercury (entered into force 16 August 2017). Sources are coal combustion, artisanal gold mining, and chlor-alkali plants, delivered to the sea by atmospheric deposition and rivers. Sulfate-reducing bacteria in anoxic sediment convert inorganic mercury to methylmercury, the form that biomagnifies. The Minamata name comes from Minamata Bay, Japan, where Chisso Corporation’s methylmercury discharge poisoned thousands from the 1950s onward.