Speaker
Description
Accelerated permafrost thaw due to a warming climate will impact cycling of contaminants such as mercury (Hg). Permafrost has typically been a sink, where Hg accumulates and is sequestered. However, it could be released with thawing. This is of concern due to the potential accumulation of Hg in country foods. This review synthesizes the results of a variety of studies done in the past 15 years on the impact of permafrost thaw on the mobilization of mercury in Arctic freshwater sources. The literature review was conducted based on a paper of interest regarding the biogeochemical cycling of Hg in thawing permafrost. Then, relevant papers that were cited by this study of interest, and papers that cited the main study were reviewed. Results show that thawing permafrost mobilizes previously sequestered Hg into freshwater systems via water and sediment. However, the production of methylmercury (MeHg) from this newly mobilized Hg is not uniform. Depending on the type of formation created by the permafrost thaw, MeHg hotspots may occur, but in other cases, MeHg does not increase with the concentration of total Hg. Concentrations of Hg were also found to be correlated to the concentration of dissolved organic carbon. Reviewing existing work makes it clear that the impacts of permafrost thaw on the cycling of Hg in the Arctic are not uniform, and monitoring of MeHg in aquatic country foods of the Arctic will be critical in the future.
