Some Sources and Sinks of Methyl and Inorganic Mercury on Ellesmere Island in the Canadian High Arctic

摘要

On Ellesmere Island in the Canadian High Arctic, we found that Hg(II) deposited to snowpacks following atmospheric Hg depletion events was rapidly (photo)reduced to Hg(0). We also observed a significant correlation between concentrations of Cl and monomethyl Hg (MMHg) in snow deposited in the spring, suggesting a marine source of MMHg. We hypothesize that dimethyl Hg produced in deep northern oceans and fluxing through open water regions in the sea ice during winter is a primary source of MMHg to some high Arctic food webs. Concentrations of MMHg in warm and shallow freshwater ponds on Ellesmere Island were also quite high, leading us to conclude that there are very active regions of microbial Hg(II) methylation in freshwater systems during the short summer season in the high Arctic.