title: Atmospheric Mercury Transfer to Peat Bogs Dominated by Gaseous Elemental Mercury Dry Deposition.
abstract: Gaseous elemental mercury (GEM) is the dominant form of mercury in the atmosphere. Its conversion into oxidized gaseous and particulate forms is thought to drive atmospheric mercury wet deposition to terrestrial and aquatic ecosystems, where it can be subsequently transformed into toxic methylmercury. The contribution of mercury dry deposition is however largely unconstrained. Here we examine mercury mass balance and mercury stable isotope composition in a peat bog ecosystem. We find that isotope signatures of living sphagnum moss (Δ(199)Hg = -0.11 ± 0.09‰, Δ(200)Hg = 0.03 ± 0.02‰, 1σ) and recently accumulated peat (Δ(199)Hg = -0.22 ± 0.06‰, Δ(200)Hg = 0.00 ± 0.04‰, 1σ) are characteristic of GEM (Δ(199)Hg = -0.17 ± 0.07‰, Δ(200)Hg = -0.05 ± 0.02‰, 1σ), and differs from wet deposition (Δ(199)Hg = 0.73 ± 0.15‰, Δ(200)Hg = 0.21 ± 0.04‰, 1σ). Sphagnum covered during three years by transparent and opaque surfaces, which eliminate wet deposition, continue to accumulate Hg. Sphagnum Hg isotope signatures indicate accumulation to take place by GEM dry deposition, and indicate little photochemical re-emission. We estimate that atmospheric mercury deposition to the peat bog surface is dominated by GEM dry deposition (79%) rather than wet deposition (21%). Consequently, peat deposits are potential records of past atmospheric GEM concentrations and isotopic composition.
authors: ECOLAB, Université de Toulouse, CNRS, INPT, UPS, France; ENSAT, Avenue de l'Agrobiopole, 31326 Castanet Tolosan, France.|Observatoire Midi-Pyrénées, Laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université Paul Sabatier Toulouse III , 14 avenue Edouard Belin, 31400 Toulouse, France.
authors: Maxime
authors: M
authors: Enrico
authors: ECOLAB, Université de Toulouse, CNRS, INPT, UPS, France; ENSAT, Avenue de l'Agrobiopole, 31326 Castanet Tolosan, France.
authors: Gaël Le
authors: GL
authors: Roux
authors: Observatoire Midi-Pyrénées, Laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université Paul Sabatier Toulouse III , 14 avenue Edouard Belin, 31400 Toulouse, France.
authors: Nicolas
authors: N
authors: Marusczak
authors: Observatoire Midi-Pyrénées, Laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université Paul Sabatier Toulouse III , 14 avenue Edouard Belin, 31400 Toulouse, France.
authors: Lars-Eric
authors: LE
authors: Heimbürger
authors: ECOLAB, Université de Toulouse, CNRS, INPT, UPS, France; ENSAT, Avenue de l'Agrobiopole, 31326 Castanet Tolosan, France.
authors: Adrien
authors: A
authors: Claustres
authors: Observatoire Midi-Pyrénées, Laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université Paul Sabatier Toulouse III , 14 avenue Edouard Belin, 31400 Toulouse, France.
authors: Xuewu
authors: X
authors: Fu
authors: Observatoire Midi-Pyrénées, Laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université Paul Sabatier Toulouse III , 14 avenue Edouard Belin, 31400 Toulouse, France.
authors: Ruoyu
authors: R
authors: Sun
authors: Observatoire Midi-Pyrénées, Laboratoire Géosciences Environnement Toulouse, CNRS/IRD/Université Paul Sabatier Toulouse III , 14 avenue Edouard Belin, 31400 Toulouse, France.
authors: Jeroen E
authors: JE
authors: Sonke
mesh_terms: D001272:Atmosphere / Q000737:chemistry*; D017753:Ecosystem; D004784:Environmental Monitoring; D005602:France; D005740:Gases / Q000032:analysis*; D005843:Geography; D008628:Mercury / Q000032:analysis*; D008629:Mercury Isotopes; D008970:Molecular Weight; D012987:Soil; D053833:Wetlands
chemical_list: D005740:Gases; D008629:Mercury Isotopes; D012987:Soil; D008628:Mercury