What controls the presence of methylmercury?
Mercury methylation and demethylation rates vary widely across the Everglades Ecosystem. Both processes are mediated by microbes that naturally occur in most environments. In most anaerobic sediments, mercury methylation exceeds demethylation rates, which is why we observed the net presence of this very toxic compound. Mercury methylation generally cannot occur in aerobic environments. Mercury methylation also requires the presence of sulfate and a reactive carbon source to drive this reaction. As such, the availability of carbon and sulfur in the correct forms is just as important as availability of mercury for the production of methylmercury.
