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Ulf Skyllberg

Ulf Skyllberg
I teach and conduct research in environmental geochemistry and soil biogeochemistry. A red thread in my research is the role played by natural organic matter, in acid-base reactions and in the geochemistry of metals and organic pollutants in soils and waters. The last 20 years my research has been much focused on mercury biogeochemistry. Recent publications cover the role of Boreal forest harvest and Boreal wetlands for the formation and export of the bio-accumulating neurotoxin methyl mercury to surface waters.


I give cources in fundamental chemistry, with a focus on thermodynamic processes (equilibrium chemsitry) relevant for soils and waters, and in geochemistry.


My current research is much focused on improving our understanding about factors and processes in control of mercury (Hg) transformations in soils and waters, such as reduction and methylation of Hg(II) and demethylation of the neurotoxin methyl mercury (MeHg). In particular I am interested in the importance of the chemical spceiation of Hg for these transformation processes. In these matters I am working closely together with Erik Björn's research group at Umeå University. Our recent findings that Boreal forest harvest increase the MeHg formation and runoff to Swedish surface waters by 12-20%, and that Black Alder swamps act as a sink for MeHg, may have implications for forest harvest practices and wetland restoration policies.


Selected publications


Thyrel, M., Backman, R., Thånell, K., Karunkaran, C., Skyllberg, U., and Lestander, T. A. 2016. Nanomapping and speciation of C and Ca in thermally treated ignocellulosic cell walls using scanning transmission X-ray microscopy and K-edge XANES. Fuel, 167, 149-157.

Kronberg, R-.M., Drott, A., Jiskra, M., Wiederhold, J.G., Björn, E., and Skyllberg, U. 2016. Forest harvest contribution to Boreal freshwater methyl mercury load. Global Biogeochem. Cycles. 30, 825-843.

Liem-Nguyen, V., Jonsson, S., Skyllberg, U., Nilsson, M.B., Andersson, A., Lundeberg, E., and Björn, E. 2016. Effects of nutrient loading and mercury chemical speciation on the formation and degradation of methylmercury in estuarine sediment. Environ. Sci. Technol. 50, 6983-6990.

Kronberg, R-.M., Jiskra, M., Wiederhold, J.G., Björn, E., and Skyllberg, U. 2016. Methyl mercury formation in hillslope soils of Boreal forests – The role of forest harvest and anaerobic microbes. Environ. Sci. Technol. 50, 9177-9186.

Shakeri Yekta, S., Skyllberg, U., Danielsson, Å., Björn, A., and Svensson, B.H. 2016. Chemical speciation of sulfur and metals in biogas reactors – Implications for cobalt and nickel bio-uptake processes. J. Haz. Mat.

Hullebusch, E.D., and 18 authors including Skyllberg, U. 2016. Methodological approaches for fractionation and speciation to estimate trace element bioavailability in engineered anaerobic digestion ecosystems: An overview. Crit. Rev. Environ. Sci. Technol. 46(16) 1324-1366.


Wiederhold, J.G., Skyllberg, U., Drott, A., Jiskra, M., Jonsson, S., Björn, E., Bourdon, B., and Kretzschmar, R. 2015. Mercury isotope signatures in contaminated sediments as a tracer for local industrial pollution sources. Environ. Sci. Technol. 49, 177−185.

Jiang, T., Skyllberg, U., Wei, S., Wang, D., Lu, S., Jiang, Z., and Flanagan, D.C. 2015. Modeling of the structure-specific kinatics of abiotic, dark reduction of Hg(II) complexed by O/N and S functional groups in humic acids while accounting for time-dependent structural rearrangement. Geochim. Cosmochim. Acta 154, 151-167.

Clarholm, M., Skyllberg, U., and Rosling, A. 2015. Organic acid induced release of nutrients from metal-stabilized soil organic matter – The unbutton model. Soil Biol. Biochem. 84, 168-176.

Jiskra, M., Wiederhold, J.G. Skyllberg, U., Kronberg, R-M., Hajdas, I., and Kretzschmar, R. 2015. Mercury deposition and re-emission pathways in boreal forest soils investigated with Hg isotope signatures. Environ. Sci. Technol. 49, 7188-7196.


Shakeri Yekta, S., Lindmark, A., Skyllberg, U., Danielsson, A., Svensson, B.H. 2014. Importance of reduced sulfur for the equilibrium chemistry and kinetics of Fe(II), Co(II) and Ni(II) supplemented to semi-continuous stirred tank biogas reactors fed with stillage. J. Haz. Mat. 269, 83-88.

Schaefer, J.K. Kronberg, R.M., Morel, F.M.M., and Skyllberg, U. 2014. Detection of a key Hg methylation gene, hgcA, in wetland soils. Environ. Microbiol. Rep. DOI: 10.1111/1758-2229.12136

Shakeri Yekta, S., Svensson, B.H., Björn, A., and Skyllberg, U. 2014. Thermodynamic modelling of iron and trace metal solubility and speciation under sulfidic and ferruginous conditions in full scale continuous stirred tank biogas reactors. Appl. Geochem. 47, 61-73.

Jonsson, S., Skyllberg, U., Nilsson, M.B., Lundberg, E., Andersson, A., and Björn, E. 2014. Differentiated availability of geochemical mercury pools control methylmercury levels in estuarine sediment and biota. Nature Comm. DOI: 10.1038/ncomms5624.


Drott, A., Björn, E., Bouchet, S., and Skyllberg, U. 2013. Refining thermodynamic constants for mercury(II)-sulfides in equilibrium with metacinnabar at sub-micromolar concentrations of dissolved sulfide. Environ. Sci. Technol. 47, 4197-4203.

Clarholm, M., and Skyllberg, U. 2013. Translocation of metals by trees and fungi regulates pH, soil organic matter turnover and nitrogen availability in acidic forest soils. Soil Biol. Biochem. 63, 142-153.

Gustavsson, J., Shakeri Yekta, S., Sundberg, C., Karlsson, A., Ejlertsson, J., Skyllberg, U., and Svensson, B.H. 2013. Bioavailability of cobalt and nickel during anaerobic digestion of sulphur-rich stillage for biogas formation. Applied Energy 112, 473-477.

Gustavsson, J., Yekta, S.S., Karlsson, A., Skyllberg, U., and Svensson, B.H. 2013. Bioavailability and chemical forms of Co and Ni in the biogas process – an evaluation based on sequential extraction and acid volatile sulfide extractions. Engineering in Life Sciences 13, 572-579.

Fernández-Gómez, C., Drott, A., Björn, E., Díez, S., Bayona, J.M, Tesfalidet, S., Lindfors, A. and Skyllberg, U. 2013. Towards universal wavelength-specific methyl mercury photodegradation rate constants in humic waters – exemplified by a boreal lake-wetland gradient. Environ. Sci. Technol. 47,6279-26287.


Tjerngren, I., Karlsson, T., Björn, E., and Skyllberg, U. 2012. Potential Hg methylation and MeHg demethylation rates related to nutrient status of different boreal wetlands. Biogeochem.  108, 335-350.

Shakeri Yekta, S., Gustavsson, J., Svensson, B.H., and Skyllberg, U. 2012. Sulfur K-edge XANES and acid volatile sulfide analyses of changes in chemical speciation of S and Fe during sequential extraction of trace metals in anoxic sludge from biogas reactors. Talanta. 89, 470-477.

Tjerngren, I., Meili, M., Björn, E., and Skyllberg, U. 2012. Eight boreal wetlands as sources and sinks for methyl mercury in relation to soil acidity, C/N ratio, and small-scale flooding. Environ. Sci. Technol. 46, 8052-8060.

Jonsson, S., Skyllberg, U., Nilsson, M.B., Westlund, P-.O., Shchukarev, A., Lundberg, E., and Björn, E. 2012. Mercury methylation rates for geochemically relevant HgII species in sediments. Environ. Sci. Technol. 46, 11653-11659.

Kronberg, R-.M., Tjerngren, I., Drott, A., Björn, E., and Skyllberg, U. 2012. Net degradation of methyl mercury in alder swamps. Environ. Sci. Technol. 46, 13144-13151.




Professor at the Department of Forest Ecology and Management; Environmental Geochemistry Unit
Telephone: +46907868460
Postal address:
Skogens ekologi och skötsel
901 83 Umeå
Visiting address: Skogsmarksgränd 17, Umeå