title: Mercury in the atmosphere, snow and melt water ponds in the North Atlantic Ocean during Arctic summer.
abstract: Atmospheric mercury speciation measurements were performed during a 10 week Arctic summer expedition in the North Atlantic Ocean onboard the German research vessel RV Polarstern between June 15 and August 29, 2004. This expedition covered large areas of the North Atlantic and Arctic Oceans between latitudes 54 degrees N and 85 degrees N and longitudes 16 degrees W and 16 degrees E. Gaseous elemental mercury (GEM), reactive gaseous mercury (RGM) and mercury associated with particles (Hg-P) were measured during this study. In addition, total mercury in surface snow and meltwater ponds located on sea ice floes was measured. GEM showed a homogeneous distribution over the open North Atlantic Ocean (median 1.53 +/- 0.12 ng/m3), which is in contrast to the higher concentrations of GEM observed over sea ice (median 1.82 +/- 0.24 ng/m3). It is hypothesized that this results from either (re-) emission of mercury contained in snow and ice surfaces that was previously deposited during atmospheric mercury depletion events (AMDE) in the spring or evasion from the ocean due to increased reduction potential at high latitudes during Arctic summer. Measured concentrations of total mercury in surface snow and meltwater ponds were low (all samples <10 ng/L), indicating that marginal accumulation of mercury occurs in these environmental compartments. Results also reveal low concentrations of RGM and Hg-P without a significant diurnal variability. These results indicate that the production and deposition of these reactive mercury species do not significantly contribute to the atmospheric mercury cycle in the North Atlantic Ocean during the Arctic summer.
authors.affiliation: Norwegian Institute for Air Research (NILU), Instituttveien 18, P.O. Box 100, N-2027, Kjeller, Norway. katrine.aspmo@nilu.no
authors.forename: Katrine
authors.initials: K
authors.lastname: Aspmo
authors.forename: Christian
authors.initials: C
authors.lastname: Temme
authors.forename: Torunn
authors.initials: T
authors.lastname: Berg
authors.forename: Christophe
authors.initials: C
authors.lastname: Ferrari
authors.forename: L Pierre-Alexis
authors.initials: LP
authors.lastname: Gauchard
authors.forename: Xavier
authors.initials: X
authors.lastname: Fain
authors.forename: Grethe
authors.initials: G
authors.lastname: Wibetoe
mesh_terms: D000393:Air Pollutants / Q000032:analysis*; D001110:Arctic Regions; D001267:Atlantic Ocean; D001272:Atmosphere / Q000737:chemistry*; D004784:Environmental Monitoring; D008628:Mercury / Q000032:analysis* / Q000737:chemistry; D017669:Mercury Compounds / Q000032:analysis; D012621:Seasons; D012623:Seawater / Q000737:chemistry*; D012914:Snow / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D000393:Air Pollutants; D017669:Mercury Compounds; D014874:Water Pollutants, Chemical; D008628:Mercury