, Volume 108, Issue 1–3, pp 335–350 | Cite as

Potential Hg methylation and MeHg demethylation rates related to the nutrient status of different boreal wetlands

  • I. TjerngrenEmail author
  • T. Karlsson
  • E. Björn
  • U. Skyllberg


Despite methylmercury (MeHg) production in boreal wetlands being a research focus for decades, little is known about factors in control of methylation and demethylation rates and the effect of wetland type. This is the first study reporting potential Hg methylation (k m ) and MeHg demethylation rate constants (k d ) in boreal wetland soils. Seven wetlands situated in northern and southern Sweden were characterized by climatic parameters, nutrient status (e.g. type of vegetation, pH, C/N ratio, specific UV-absorption), iron and sulfur biogeochemistry. Based on nutrient status, the wetlands were divided into three groups; (I) three northern, nutrient poor fens, (II) a nutrient gradient ranging from an ombrotrophic bog to a fen with intermediate nutrient status, and (III) southern, more nutrient rich sites including two mesotrophic wetlands and one alder (Alnus) forest swamp. The k m /k d ratio in general followed %MeHg in soil and both measures were highest at the fen site with intermediate nutrient status. Northern nutrient poor fens and the ombrotrophic bog showed intermediate values of %MeHg and k m /k d . The two mesotrophic wetlands showed the lowest %MeHg and k m /k d , whereas the alder swamp had high k m and k d , resulting in an intermediate k m /k d and %MeHg. Molybdate addition experiments suggest that net MeHg production was mainly caused by the activity of sulfate reducing bacteria. A comparison with other studies, show that k m and %MeHg in boreal freshwater wetlands in general are higher than in other environments. Our results support previous suggestions that the highest MeHg net production in boreal landscapes is to be found in fens with an intermediate nutrient status.


Methylmercury Mercury Wetlands Methylation Demethylation 



Bengt Andersson and Anna Persson, SLU-Umeå, are gratefully acknowledged for assistance in the laboratory. A special thanks to Per Peterson at Sveaskog AB and Torbjörn Åhman, Holmen Skog AB for support throughout the project, and help with selection of wetlands. Anders Rydberg, Ulf Zander, Conny Henriksson and Claes Scholander, Sveaskog AB and Lars-Rune Larsson, Holmen Skog AB, are gratefully acknowledged for their field work. The financial support was provided by The Swedish Research Council for Environment, Agricultural Sciences and Spatial Planning (Formas) (Project No. 214-2005-1462), the Oscar & Lili Lamm foundation and the Kempe foundations.

Supplementary material

10533_2011_9603_MOESM1_ESM.doc (168 kb)
Supplementary material 1 (DOC 167 kb).


  1. Barkay T, Gillman M, Turner RR (1997) Effects of dissolved organic carbon and salinity on bioavailability of mercury. Appl Environ Microbiol 63(11):4267–4271Google Scholar
  2. Benoit JM, Gilmour CC, Mason RP, Heyes A (1999) Sulfide controls on mercury speciation and bioavailability to methylating bacteria in sediment pore waters. Environ Sci Technol 33(6):951–957. doi: 10.1021/es9808200 CrossRefGoogle Scholar
  3. Benoit JM, Gilmour CC, Heyes A, Mason RP, Miller CL (2003) In: Cai Y, Braids OC (eds) Geochemical and biological controls over methylmercury production and degradation in aquatic ecosystems. American Chemical Society, pp 262–297Google Scholar
  4. Branfireun BA, Roulet NT (2002) Controls on the fate and transport of methylmercury in a boreal headwater catchment, northwestern Ontario, Canada. Hydrol Earth Syst Sci 6(4):783–794CrossRefGoogle Scholar
  5. Compeau GC, Bartha R (1987) Effect of salinity on mercury-methylating activity of sulfate-reducing bacteria in estuarine sediments. Appl Environ Microbiol 53(2):261–265Google Scholar
  6. Drott A, Lambertsson L, Bjorn E, Skyllberg U (2007) Importance of dissolved neutral mercury sulfides for methyl mercury production in contaminated sediments. Environ Sci Technol 41(7):2270–2276. doi: 10.1021/es061724z CrossRefGoogle Scholar
  7. Drott A, Lambertsson L, Bjoern E, Skyllberg U (2008a) Do potential methylation rates reflect accumulated methyl mercury in contaminated sediments? Environ Sci Technol 42(1):153–158. doi: 10.1021/es0715851 CrossRefGoogle Scholar
  8. Drott A, Lambertsson L, Bjorn E, Skyllberg U (2008b) Potential demethylation rate determinations in relation to concentrations of MeHg, Hg and pore water speciation of MeHg in contaminated sediments. Mar Chem 112(1–2):93–101. doi: 10.1016/j.marchem.2008.07.002 CrossRefGoogle Scholar
  9. Fellman JB, D’Amore DV, Hood E, Boone RD (2008) Fluorescence characteristics and biodegradability of dissolved organic matter in forest and wetland soils from coastal temperate watersheds in southeast Alaska. Biogeochemistry 88(2):169–184. doi: 10.1007/s10533-008-9203-x CrossRefGoogle Scholar
  10. Fitzgerald WF, Clarkson TW (1991) Mercury and monomethylmercury—present and future concerns. Environ Health Perspect 96:159–166CrossRefGoogle Scholar
  11. Fitzgerald WF, Lamborg CH, Hammerschmidt CR (2007) Marine biogeochemical cycling of mercury. Chem Rev 107(2):641–662. doi: 10.1021/cr050353m CrossRefGoogle Scholar
  12. Fleming EJ, Mack EE, Green PG, Nelson DC (2006) Mercury methylation from unexpected sources: molybdate-inhibited freshwater sediments and an iron-reducing bacterium. Appl Environ Microbiol 72(1):457–464. doi: 10.1128/AEM.72.1.457-464.2006 CrossRefGoogle Scholar
  13. Gilmour CC, Henry EA, Mitchell R (1992) Sulfate stimulation of mercury methylation in fresh-water sediments. Environ Sci Technol 26(11):2281–2287CrossRefGoogle Scholar
  14. Gilmour CC, Riedel GS, Ederington MC, Bell JT, Benoit JM, Gill GA, Stordal MC (1998) Methylmercury concentrations and production rates across a trophic gradient in the northern Everglades. Biogeochemistry 40:327–345CrossRefGoogle Scholar
  15. Golding GR, Sparling R, Kelly CA (2008) Effect of pH on intracellular accumulation of trace concentrations of Hg(II) in Escherichia coli under anaerobic conditions, as measured using a mer-lux bioreporter. Appl Environ Microbiol 74(3):667–675. doi: 10.1128/aem.00717-07 CrossRefGoogle Scholar
  16. Hammerschmidt CR, Fitzgerald WF (2006) Methylmercury cycling in sediments on the continental shelf of southern New England. Geochim Cosmochim Acta 70:918–930. doi: 10.1016/j.gca.2005.10.020 CrossRefGoogle Scholar
  17. Kelly CA, Rudd JWM, Holoka MH (2003) Effect of pH on mercury uptake by an aquatic bacterium: implications for Hg cycling. Environ Sci Technol 37(13):2941–2946. doi: 10.1021/es026366o CrossRefGoogle Scholar
  18. Kerin EJ, Gilmour CC, Roden E, Suzuki MT, Coates JD, Mason RP (2006) Mercury methylation by dissimilatory iron-reducing bacteria. Appl Environ Microbiol 72(12):7919–7921. doi: 10.1128/AEM.01602-06 CrossRefGoogle Scholar
  19. Lambertsson L, Bjorn E (2004) Validation of a simplified field-adapted procedure for routine determinations of methyl mercury at trace levels in natural water samples using species-specific isotope dilution mass spectrometry. Anal Bioanal Chem 380(7–8):871–875CrossRefGoogle Scholar
  20. Lambertsson L, Nilsson M (2006) Organic material: the primary control on mercury methylation and ambient methyl mercury concentrations in estuarine sediments. Environ Sci Technol 40(6):1822–1829. doi: 10.1021/es051785h CrossRefGoogle Scholar
  21. Lambertsson L, Lundberg E, Nilsson M, Frech W (2001) Applications of enriched stable isotope tracers in combination with isotope dilution GC–ICP–MS to study mercury species transformation in sea sediments during in situ ethylation and determination. J Anal At Spectrom 16(11):1296–1301. doi: 10.1039/b106878b CrossRefGoogle Scholar
  22. Larsson T, Frech W (2003) Species-specific isotope dilution with permeation tubes for determination of gaseous mercury species. Anal Chem 75(20):5584–5591CrossRefGoogle Scholar
  23. Liu RH, Wang QC, Lu XG, Fang FM, Wang Y (2003) Distribution and speciation of mercury in the peat bog of Xiaoxing’an Mountain, northeastern China. Environ Pollut 124(1):39–46. doi: 10.1016/s0269-7491(02)00432-3 CrossRefGoogle Scholar
  24. Loseto LL, Siciliano SD, Lean DRS (2004) Methylmercury production in High Arctic wetlands. Environ Toxicol Chem 23(1):17–23CrossRefGoogle Scholar
  25. Marvin-Dipasquale MC, Oremland RS (1998) Bacterial methylmercury degradation in Florida Everglades peat sediment. Environ Sci Technol 32(17):2556–2563CrossRefGoogle Scholar
  26. Mehrotra AS, Sedlak DL (2005) Decrease in net mercury methylation rates following iron amendment to anoxic wetland sediment slurries. Environ Sci Technol 39(8):2564–2570CrossRefGoogle Scholar
  27. Mehrotra AS, Horne AJ, Sedlak DL (2003) Reduction of net mercury methylation by iron in Desulfobulbus propionicus (1pr3) cultures: implications for engineered wetlands. Environ Sci Technol 37(13):3018–3023. doi: 10.1021/es0262838 CrossRefGoogle Scholar
  28. Merritt KA, Amirbahman A (2009) Mercury methylation dynamics in estuarine and coastal marine environments—a critical review. Earth-Sci Rev 96(1–2):54–66. doi: 10.1016/j.earscirev.2009.06.002 CrossRefGoogle Scholar
  29. Mitchell CPJ, Gilmour CC (2008) Methylmercury production in a Chesapeake Bay salt marsh. J Geophys Res 113:14. doi: 10.1029/2008JG000765 CrossRefGoogle Scholar
  30. Mitchell CPJ, Branfireun BA, Kolka RK (2008a) Assessing sulfate and carbon controls on net methylmercury production in peatlands: an in situ mesocosm approach. Appl Geochem 23:503–518. doi: 10.1016/j.apgeochem.2007.12.020 CrossRefGoogle Scholar
  31. Mitchell CPJ, Branfireun BA, Kolka RK (2008b) Spatial characteristics of net methylmercury production hot spots in peatlands. Environ Sci Technol 42(4):1010–1016. doi: 10.1021/eso0704986 CrossRefGoogle Scholar
  32. Oremland RS, Culbertson CW, Winfrey MR (1991) Methylmercury decomposition in sediments and bacterial cultures—involvement of methanogens and sulfate reducers in oxidative demethylation. Appl Environ Microbiol 57(1):130–137Google Scholar
  33. Pak KR, Bartha R (1998) Mercury methylation and demethylation in anoxic lake sediments and by strictly anaerobic bacteria. Appl Environ Microbiol 64(3):1013–1017Google Scholar
  34. Qvarnstrom J, Frech W (2002) Mercury species transformations during sample pre-treatment of biological tissues studied by HPLC–ICP–MS. J Anal At Spectrom 17(11):1486–1491. doi: 10.1039/b205246f CrossRefGoogle Scholar
  35. Reis MAM, Almeida JS, Lemos PC, Carrondo MJT (1992) Effect of hydrogen-sulfide on growth of sulfate reducing bacteria. Biotechnol Bioeng 40(5):593–600CrossRefGoogle Scholar
  36. Roulet M, Guimaraes JRD, Lucotte M (2001) Methylmercury production and accumulation in sediments and soils of an amazonian floodplain—effect of seasonal inundation. Water Air Soil Pollut 128(1–2):41–60CrossRefGoogle Scholar
  37. Selin NE (2009) Global biogeochemical cycling of mercury: a review. Annu Rev Environ Resour 34:43–63. doi: 10.1146/annurev.environ.051308.084314 CrossRefGoogle Scholar
  38. Selvendiran P, Driscoll CT, Montesdeoca MR, Bushey JT (2008) Inputs, storage, and transport of total and methyl mercury in two temperate forest wetlands. J Geophys Res 113. doi: 10.1029/2008jg000739
  39. Skyllberg U (2008) Competition among thiols and inorganic sulfides and polysulfides for Hg and MeHg in wetland soils and sediments under suboxic conditions: Illumination of controversies and implications for MeHg net production. J Geophys Res 113. doi: G00c0310.1029/2008jg000745
  40. Skyllberg U, Qian J, Frech W, Xia K, Bleam WF (2003) Distribution of mercury, methyl mercury and organic sulphur species in soil, soil solution and stream of a boreal forest catchment. Biogeochemistry 64(1):53–76CrossRefGoogle Scholar
  41. Snell JP, Stewart II, Sturgeon RE, Frech W (2000) Species specific isotope dilution calibration for determination of mercury species by gas chromatography coupled to inductively coupled plasma- or furnace atomisation plasma ionisation-mass spectrometry. J Anal At Spectrom 15(12):1540–1545CrossRefGoogle Scholar
  42. Soil Survey Staff (2010) Keys to soil taxonomy, 11th edn. USDA-Natural Resources Conservation Service, WashingtonGoogle Scholar
  43. St. Louis VL, Rudd JWM, Kelly CA, Beaty KG, Flett RJ, Roulet NT (1996) Production and loss of methylmercury and loss of total mercury from boreal forest catchments containing different types of wetlands. Environ Sci Technol 30(9):2719–2729CrossRefGoogle Scholar
  44. St. Louis VL, Rudd JWM, Kelly CA, Bodaly RA, Paterson MJ, Beaty KG, Hesslein RH, Heyes A, Majewski AR (2004) The rise and fall of mercury methylation in an experimental reservoir. Environ Sci Technol 38(5):1348–1358CrossRefGoogle Scholar
  45. US EPA (2002) Method 1631, mercury in water by oxidation, purge and trap, and cold vapor atomic fluorescence spectrometryGoogle Scholar
  46. Viollier E, Inglett PW, Hunter K, Roychoudhury AN, Van Cappellen P (2000) The ferrozine method revisited: Fe(II)/Fe(III) determination in natural waters. Appl Geochem 15(6):785–790CrossRefGoogle Scholar
  47. Warner KA, Roden EE, Bonzongo JC (2003) Microbial mercury transformation in anoxic freshwater sediments under iron-reducing and other electron-accepting conditions. Environ Sci Technol 37(10):2159–2165. doi: 10.1021/es0262939 CrossRefGoogle Scholar
  48. Weishaar JL, Aiken GR, Bergamaschi BA, Fram MS, Fujii R, Mopper K (2003) Evaluation of specific ultraviolet absorbance as an indicator of the chemical composition and reactivity of dissolved organic carbon. Environ Sci Technol 37(20):4702–4708. doi: 10.1021/es030360x CrossRefGoogle Scholar
  49. Windham-Myers L, Marvin-Dipasquale M, Krabbenhoft DP, Agee JL, Cox MH, Heredia-Middleton P, Coates C, Kakouros E (2009) Experimental removal of wetland emergent vegetation leads to decreased methylmercury production in surface sediment. J Geophys Res 114. doi: G00c0510.1029/2008jg000815
  50. Zar JH (1996) Biostatistical analysis. Prentice-Hall International (UK) Limited, LondonGoogle Scholar

Copyright information

© Springer Science+Business Media B.V. 2011

Authors and Affiliations

  • I. Tjerngren
    • 1
    Email author
  • T. Karlsson
    • 2
  • E. Björn
    • 2
  • U. Skyllberg
    • 1
  1. 1.Department of Forest Ecology and ManagementSwedish University of Agricultural SciencesUmeåSweden
  2. 2.Department of ChemistryUmeå UniversityUmeåSweden

Personalised recommendations