Summary of geochemistry field research

From APLIS07

Global atmospheric circulation and unique polar chemistry concentrates pollutants in the high Arctic. One such pollutant, mercury, is preferentially deposited in the Arctic during springtime due to unique photochemistry. The SNACS-mercury project, led by Bill Simpson from the University of Alaska Fairbanks, is investigating this chemistry and how it depends on environmental conditions, e.g. sea ice extent and temperature, many of which are undergoing changes. A critical player in the atmospheric chemistry that causes mercury deposition is bromide, a trace ion in sea salt. Normally, sea salt is chemically inert, but springtime chemistry converts these salts to reactive halogen species that then cause mercury deposition. The specific focus of this ice camp campaign is to quantify the chemical nature and amount of atmospherically accessible sea salts on the sea ice and how their abundance depends on the type of ice / snow (i.e. snow, first year ice, multi year ice, frost flowers, etc.) in which they occur. We can then model how the salts affect atmospheric chemistry and determine the dependence of mercury deposition on sea ice conditions. Global climate models that predict future sea ice state can then be used to extrapolate future Arctic mercury deposition intensity, improving understanding of how this will affect human health in the Arctic.