Microbes and mercury biogeochemical cycle in the Venice lagoon

The Venice lagoon is an environment threatened by pollution and bottom floor erosion which are both leading to a rapid decline of the ecosystem. Mercury is a pollutant of major concern since its high toxicity and capability of bio accumulate in the food chain present in the lagoon sediment because of the long period activity of the Marghera chemical plant. Microbes play a central role in the element biogeochemical cycle and among them sulfate-reducing bacteria are well know to produce methyl-mercury, one of the most poisonous mercury compound. In the frame of the SIOSED project, sediment from the Venice lagoon have been dredged and used to build sub-tidal banks with the meaning of keeping shipping channel clean and improving the diversity of the bottom floor. The microbial community in the sites of interest for the project have been studied for a total of two year period in order to monitor the effects of sediment dredging and transplanting on methyl-mercury production