title: Mercury distribution and transport across the ocean-sea-ice-atmosphere interface in the Arctic Ocean.
abstract: The Arctic sea-ice environment has been undergoing dramatic changes in the past decades; to which extent this will affect the deposition, fate, and effects of chemical contaminants remains virtually unknown. Here, we report the first study on the distribution and transport of mercury (Hg) across the ocean-sea-ice-atmosphere interface in the Southern Beaufort Sea of the Arctic Ocean. Despite being sampled at different sites under various atmospheric and snow cover conditions, Hg concentrations in first-year ice cores were generally low and varied within a remarkably narrow range (0.5-4 ng L(-1)), with the highest concentration always in the surface granular ice layer which is characterized by enriched particle and brine pocket concentration. Atmospheric Hg depletion events appeared not to be an important factor in determining Hg concentrations in sea ice except for frost flowers and in the melt season when snowpack Hg leaches into the sea ice. The multiyear ice core showed a unique cyclic feature in the Hg profile with multiple peaks potentially corresponding to each ice growing/melting season. The highest Hg concentrations (up to 70 ng L(-1)) were found in sea-ice brine and decrease as the melt season progresses. As brine is the primary habitat for microbial communities responsible for sustaining the food web in the Arctic Ocean, the high and seasonally changing Hg concentrations in brine and its potential transformation may have a major impact on Hg uptake in Arctic marine ecosystems under a changing climate.
authors.affiliation: Department of Environment and Geography, University of Manitoba, Center for Earth Observation Science, Winnipeg, Manitoba R3T 2N2, Canada.
authors.forename: Amanda
authors.initials: A
authors.lastname: Chaulk
authors.forename: Gary A
authors.initials: GA
authors.lastname: Stern
authors.forename: Debbie
authors.initials: D
authors.lastname: Armstrong
authors.forename: David G
authors.initials: DG
authors.lastname: Barber
authors.forename: Feiyue
authors.initials: F
authors.lastname: Wang
mesh_terms: D000392:Air Movements; D000393:Air Pollutants / Q000032:analysis* / Q000737:chemistry; D001110:Arctic Regions; D001272:Atmosphere / Q000737:chemistry*; D004784:Environmental Monitoring; D007053:Ice / Q000032:analysis*; D008628:Mercury / Q000032:analysis* / Q000737:chemistry; D009792:Oceans and Seas; D012492:Salts / Q000737:chemistry; D012623:Seawater / Q000737:chemistry; D014872:Water Movements; D014874:Water Pollutants, Chemical / Q000032:analysis* / Q000737:chemistry
chemical_list: D000393:Air Pollutants; D007053:Ice; D012492:Salts; D014874:Water Pollutants, Chemical; C017082:brine; D008628:Mercury