|Abstract Title:||Speciation and Distribution of Mercury in the Water Column and Sediments of the Bering and Chukchi Seas|
|Presenter Name:||Hannah Inman|
|Company/Institution:||University of Connecticut|
|Session:||Special Session - Climate-Driven Perturbations of Arctic Mercury Cycling|
|Co-Authors:||Hannah Inman,Robert Mason,Yipeng He|
Abstract Information :
The Arctic is a known sink of atmospheric mercury (Hg) and source of neurotoxic and biomagnifying methylated mercury (MeHg) compounds such as dimethylmercury (DMHg) and monomethylmercury (MMHg). The bioaccumulation of MMHg into seafood and marine mammals consumed by people is an important human health concern. Two important steps in the cycling of mercury species at the air-sea interface in the Arctic are the atmospheric deposition of inorganic Hg and the evasion of Hg0 and DMHg, both of which are not yet well constrained given the impact of ice cover and other factors, which are changing due to climate change. Additionally, sediment and riverine inputs of Hg and MMHg are poorly constrained. Estimating the magnitude of net external inorganic Hg and MMHg inputs to the Arctic is complicated by the lack of information on the distribution of methylated and total mercury species in the polar mixed layer and sediments, and of the internal conversion between Hg forms. Here we report the preliminary results of studies completed in May/June 2021 aboard the RV Sikuliaq in the Bering and Chukchi Seas. Waters were mostly shallow (less than 100 m) and water (dissolved and particulate) and sediment samples (solid and porewater) were collected and analyzed for Hg0 and DMHg on board and later analyzed for mercury and total methylated mercury, to assess the distribution of mercury species through the water column, sediments, at the sediment-water interface, and potential fluxes. The results of these studies will be presented. Overall, this study has further resolved the distribution of mercury species in the water column and sediments in this area, allowing for an improved understanding of the Arctic mercury biogeochemical cycle, and the exchange of Hg at the sediment-water and ocean-atmosphere interfaces.