Espen Lydersen


Fakultet for teknologi, naturvitenskap og maritime fag
Institutt for natur, helse og miljø
Campus Bø ()



PhD from the University of Oslo (UiO) in 1992. Worked as researcher at the Norwegian Institute for Water Research (NIVA) from 1991 -2007, from 2000 in a 50 % position as senior researcher at NIVA combined with a 50% position as special investigator at Økokrim (The Norwegian national authority for investigation and prosecution  economic and environmental crime), primarily related to water pollution trials. Since August 2007, employed as professor in limnology at Telemark University College (University College of Southeast Norway from 01.01.2016).

Main scientific competence within various water-chemical issues, especially related to toxic compounds and their effects in the environment. Has been project leader of the EU-funded HUMEX-project (1994-1996), focusing on natural organic matter and acidification, including 8 European countries. From 1997-2004, Lydersen was the leader of a WB/NORAD funded project in China (1997-2004), with main focus on establishment of standardized monitoring field stations, laboratories and analyses, as well as transfer of scientific competence/experience within acid rain research and subsequent countermeasures. 7 Norwegian and 13 Chinese institutions participated. As one of the inventors of an eco-friendly method for elimination of the very lethal salmon parasite Gyrodactylus salaris, Lydersen was leading a research and water treatment group for 7 years (2000-2007), in order to fight this threat. In 2009-2012, Lydersen was leader of the research project Pyrowater, funded by the Norwegian Research Council, with main focus on physcio-chemical and biological effects of wildfire on lakes. In the period 2004-2007, Lydersen was member of the scientific committee within Evolution biology and ecological disciplines in the Norwegian Research Council. Lydersen has a broad national and international network, have and do supervise many master- and PhD candidates and have broad experience as opponent/examiner related to master and PhD thesis. He has published about 150 scientific articles/reports.




Olsen, M.; Schaanning, M.T., Veiteberg Braaten, H.F.; Eek, E., Moy, F.E., Lydersen, E. (2018). The influence of permanently submerged macrophytes on sediment mercury distribution, mobility and methylation potential in a brackish Norweigian fjord. The Sci. Total Environm.  DOI:10.1016/j.scitotenv.2017.08.136

Lydersen, C. Vaquie-Garcia1, J., Lydersen, E., Christensen, G.N., Kovacs, K.M. (2017). Novel terrestrial haul-out behaviour by ringed seals (Pusa hispida) in Svalbard and  association with harbour seals (Phoca vitulina). Polar Research 36, 1374124.

Braaten, H.F. Veiteberg; Åkerblom, S.; de Wit, H.A.; Skotte, G.; Rask, M.; Vuorenmaa, J.; Kahilainen, K.K.; Malinen, T.; Rognerud, S.; Lydersen, E.; Amundsen, P.-A.; Kashulin, N.; Kashulina, T.; Terentyev, P.; Christensen, G.; Jackson-Blake,L.; Lund, E.; Rosseland, B.O. (2017). Spatial and temporal trends of mercury in freshwater fish in Fennoscandia (1965-2015). ICP Waters report 132/2017, 70 pp. ISBN 978-82-577-6914-7.

Økelsrud, A., Lydersen, E., Moreno, A., Fjeld, E. (2017). Mercury and selenium in free-ranging brown trout (Salmo trutta) in the River Skienselva watercourse, Southern Norway.  The Sci. Total Environm. DOI:10.1016/j.scitotenv.2017.01.199

Olsen, M., Sørensen, C., Lydersen, E. (2016).Mercury in the submerged macrophytes Potamogeton crispus and Chara virgate from the brackish, industrial affected Gunneklevfjorden, southern Norway. Vann' 51 (3), 

Olk, T.R., Karlsson, T., Lydersen, E., Økelsrud, A. (2016). Seasonal variations in the use of profundal habitat among freshwater fishes in Lake Norsjø, southern Norway, and subsequent effects on fish mercury concentrations. Environments., 3(4), 29; 21 pp. doi:10.3390/environments3040029.

Lydersen, E. Høgberget, R. Holtan, M., Darrud, M., Moreno, C.E. (2016). Effects of wildfire on water chemistry and perch (Perca fluviatilis) populations in some acidic lakes in southern Norway. Vann, 51 (2), 129-141.

Økelsrud, A., Lydersen, E., Fjeld, E. (2016). Biomagnification of mercury and selenium in two lakes in southern Norway. The Sci. Total Environm., 566-567, 596-607. DOI: 10.1016/j.scitotenv.2016.05.109.

Lydersen, E. and Moreno, C. (2016). Variations in feeding habitats and mercury levels in fish from Lake Norsjø, southern Norway. Vann, 51(4), 381-404.

Moreno, C., Fjeld E., Lydersen, E. (2015). The effects of wildfire on mercury and stable isotopes (δ15N, δ13C) in water and biota of small boreal, acidic lakes in southern Norway. Environm. Monitor. Assessm.188:178.DOI 10.007/s10661-016-5148-z.

Moreno, C, Fjeld, E., Deshar, MK and Lydersen, E. (2015). Seasonal variations in mercury and d15N in fish from Lake Heddalsvatn,  Southern Norway. J. Limnology, 74 (1), 21-30. (DOI 10.4081/jlimnol.2014.918)

Lydersen, E., Høgberget, R., Moreno, C., Garmo, O., Hagen, P.C. (2014). The effects of wildfire on the water chemistry of dilute, acidic lakes in southern Norway. Biogeochemistry, 119 109-124; or 117 (DOI 10.1007/s10533-014-9951-8).

Braaten, H.F.V., DeWit, H.A., Fjeld E., Rognerud, S., Lydersen, E., Larssen, T. (2014). Environmental factors influencing mercury speciation and methylmercury production rates in boreal lakes. The Sci.Total Environm., 476-477, 336-345.

Lydersen, E., Holtan, M., Darrud, D. (2013). Vannkjemiske effekter av avsmelting fra et snødeponi. Vann, 4, 

Kure, E.H; Heggenes, J.; Sæbø, M.; Stangeland, A.M.; Hamfjord, J.; Hytterød, S.; Lydersen, E. (2013). Molecular responses to toxicological stressors: Profiling microRNAs in wild Atlantic salmon (Salmo salar) exposed to acidic aluminum-rich water. Aquatic Toxicology, 138-139, 98-104. 

Lydersen, E., Aanes, K.J., Andersen, S., Andersen, T., Brettum, P., Bekken, T. Lien, L., Lindstrøm, E.A., Løvik, J.E., Mjelde, M., Oredalen, T.J., Solheim, A.L. Romstad, R. og Wright, R.F. (2008). Ecosystem effects of thermal manipulation of a whole lake, Lake Breisjøen, southern Norway (Thermos project). Hydrol. Earth System Sciences,12, 509-522.

Larssen, T. Lydersen, E., Tang, D., He, Y., Gao, J., Liu, H., Duan, L., Seip, H.M., Vogt, R.D., Mulder, J., Dhao, M.,Wang, Y., Shang, H., Zhang, X., Solberg, S., Aas, W., Økland, T., Eilertsen, O., Angel, V., Lui, Q., Zhao, D., Xiang, R., Xiao, J., Luo, J. (2006). Acid Rain in China. Environm. Sci. Technol., 15, 418-425.

Alstad, N.E.W., Kjelsberg, B.M., Vøllestad, L.A., Lydersen, E., Poléo, A.B.S (2005). The significance of water ionic strength on Al-toxicity in brown trout (Salmo trutta L). Environm. Pollut., 133, 333-342.

Poléo, A.B.S., Lydersen, E., Mo, T.A. (2004)  Aluminium mot lakseparasitten Gyrodactylus salaris. Norsk Veterinærtidskrift, 3, 176-180.

Poléo, A.B.S., Schjolden, J., Hansen, H., Bakke, T.A., Rosseland, B.O., Lydersen, E. (2004). The effect of various metals on Gyrodactylus salaris (Platyhelminthes, Monogena) infections in Atlantic salmon (Salmo salar). Parasitology, 128, 169-177.

Lydersen, E., Larssen, T., Fjeld E. (2004). The influence of total organic carbon (TOC) on the relationship between acid neutralizing capacity (ANC) and fish status in Norwegian lakes. The Sci. Tot. Environm, 362, 63-69.

Lydersen, E., Löfgren, S. (2002). Potential effects of metals in reacidified limed water bodies in Norway and Sweden. Environm. Monitor. Assessment, 73, 155-178.

Lydersen, E., Löfgren, S., Arnesen, R.T. (2002). Metals in Scandinavian Surface waters: Effects of Acidification, Liming and Potential Re-acidification. Critical Reviews in Environm. Sci and Technology, 32,73-295.

Lydersen, E., Rukke, N.A., Jensen, J.G.B., Kjelsberg, B.M., Tornsjø, B., Vogt, R.D., Vøllestad, L.A., Poléo, A.B.S. (2002). Seasonal variation in mortality of brown trout (Salmo trutta) in an acidic aluminium- rich lake. J. Limnol., 61, 61-68.

Lydersen, E., Øxnevad, S. Østbye, K., Andersen, R.A., Bjerkely, F.,  Vøllestad, L.A., Poléo, A.B.S. (2002). The effects of ionic strength on the toxicity of aluminium to Atlantic salmon (Salmo salar) under non-steady state chemical conditions. J. Limnol., 61, 69-76.

Lydersen, C., Kovacs, K., Lydersen, E. (2001). Rust-colored bearded (Erignathus barbatus) and ringed (Phoca hispida) seals from Svalbard, Norway. J. Marin Mammal., 82, 225-230.

Tang, Dagang, Lydersen, E., Seip, H.M., Angell, V., Eilertsen, O., Larssen, T., Liu Xin, Kong Guohui, Mulder,J., Semb, A., Solberg, S., Torseth, K., Vogt, R.D., Xioa Jinshong, Zhao Dawei (2001). Intergrated Monitoring Program on Acidification of Chinese terrestrial systems (IMPACTS) - A Chinese-Norwegian Cooperation Project.  Water, Air, Soil Pollut., 130, 1073-1078.

Lydersen, E., Löfgren, S. (2000). Vad händer när kalkade sjøer återforsuras ? En kunskapsöversikt och riskanalys. What happens when limed water bodies reacidify ? A summary of a state of the art review and a risk analysis. Swedish Environmental Agency (SNV), SNV-report 5074, 76 pp.

Seip, H.M., Aaagard, P., Angell, V., Larssen, T., Lydersen, E., Mulder, J., Muniz, I.P., Semb, A., Vogt, R.D., Jinshong, X., Jiling, X., Zhao Dawei, Kong Guohui. (1999). Acidification in China: Assessment based on studies at forested sites from Chongqing and Guangzhou. Ambio, 28, 522-528.

Larssen, T., Seip, H.M., Semb, A., Mulder, J., Muniz, I.P., Vogt, R.D., Lydersen, E., Angell, V., Tang, D., Eilertsen, O. (1999). Acid deposition and its effects in China – an overview. Environ. Sci. and Policy, 2, 9-2.

Gjessing, E.T., Riise, G. and Lydersen, E. (1998). Acid rain and natural organic matter (NOM). Acta Hydrochim. Hydrobiol. 26, 131-136.

Gjessing, E.T., Alberts, J., Bruchet, A., Egeberg, P.K., Lydersen, E., McGown, L.B., Mobed, J.J., Munster, U., Pempkowiak, J., Perdue, M., Ratnawerra, H., Rybacki, D., Takacs, M., Abbt-Braun, G. (1998). Multi-method charcterisation of natural organic matter (NOM) isolated from water: Characterisation of reverse osmosis-isolates from water of two semi-indentical dystrophic lake basins in Norway. Water Research, 32, 3108-3124.

Lydersen, Espen (1998). Humus and acidification. In: D.O. Hessen and L. Tranvik (eds.) Aquatic Humic Substances, Ecology and Biogeochemistry, Ecological Studies 133. Springer-Verlag, 63-92.

Hindar, A., Kroglund, F., Lydersen, E., Skiple, A., and Høgberget, R. (1996). Liming of wetlands in the acidified Røynelandsvatn catchment in Southern Norway: effects on stream water chemistry. Can. J. Fish Aquat. Sci. 53, 985-993.

Hessen, D.O. and Lydersen, E. (1996). The zooplankton story of humic lake Skjervatjern during whole catchment acidification. Environmental International,  22, 643-652.

Verbost, P., Berntssen, M.H.G., Kroglund, F., Lydersen, E., Witters, H.E., Rosseland, B.O. and Wendelaar Bonga, S.E. (1995). The toxic mixing zone of natural and acidic river water: Acute aluminium toxicity in brown trout (Salmo trutta L.), Water, Air, Soil, Pollut. 85, 341-346.

Lydersen, E., Fjeld, E. and Gjessing, E.T. (1995). The humic lake acidification experiment (HUMEX): Main physico-chemical results after five years of artificial acidification. Environmental International, 22, 591-604.

Poppe, T., Holtet, L., Bjerknes, V., og Lydersen, E. (1995) Kalsiumutfelling i nyrene hos regnbueørret i sjøvannoppdrett. (Calcium precipitation in the kidneys of rainbow trout (Oncorhynchus mykiss) in seawater fishfarming. Norsk Veterinærtidskrift, 107, 131-137.

Lydersen, E., and Henriksen, A. (1995). Seasalt effects on the acid neutralising capacity of streamwaters in southern Norway. Nordic Hydrology,  26, 369-388.

Kirchner, M. and Lydersen, E (1995). Base cation depletion and potential long-term acidification of Norwegian catchments. Environm. Science & Technol., 29, 1953-1960.

Lydersen, E. (1995). Effects of cold and warm years on the water chemistry at the Birkenes catchment, Norway. Water, Air, Soil Pollut. 84, 217-232.1994

Lydersen, E. (1995). Sammenlikning mellom hydrologisk-år og kalender-år for massebalanse-beregninger ved fire feltforskningsområder i Norge (Comparison between hydrologic-year and calendar-year for mass-balance calculations at four Norwegian long term monitored catchments), Limnos, 1, 8-11.

Polèo, A.B.S., Lydersen, E., Rosseland, B.O., Kroglund, F., Salbu, B., Vogt, R., and Kvellestad, A. (1994). Increased mortality of fish due to changing Al-chemistry of mixing zones between limed streams and acid tributaries, Water, Air, Soil Pollut., 75, 339-352.

Hindar, A. and Lydersen, E. (1994). Extreme acidification of a lake in southern Norway caused by weathering of sulphide-containing bedrock. Water, Air, Soil Pollut.,  77, 17-25.

Lydersen, E. and Henriksen, A. (1994). Total organic carbon in streamwater from four long-term monitored catchments in Norway.  Environm. Internat.,  20, 713-729.

Lydersen, E., Kroglund, F., Nandrup Pettersen, M.,  Polèo, A.B.S., Rosseland, B.O., Riise, G., and Salbu, B. (1994). The importance of "in situ" measurements to relate toxicity and chemistry in dynamic aluminium freshwater systems. J. Ecol. Chem., 3, 357-265.

Lydersen, E., Polèo, A.B.S, Oughton, D.H., and Salbu, B. (1993). Addition of sulphuric acid to high organic carbon lake water: Effects of macro-chemistry, aluminium and iron. Water, Air, Soil Pollut., 66, 349-363.

Rosseland, B.O., Blakar, I., Bulger, A, Kroglund, F., Kvellestad, A., Lydersen, E., Oughton, D.H., Salbu, B., Staurnes, M. and Vogt, R. (1992). The mixing zone between limed and acid river waters: complex aluminium chemistry and extreme toxicity for salmonids. Environmental Pollution, 78, 3-8.

Lydersen, E., Salbu, B. and Polèo, A.B.S. (1992). Size and charge fractionation of aqueous aluminium in dilute acidic waters - Effects of pH and temperature changes. Analyst, 117, 613-617.

Polèo, A.B.S, Lydersen, E., and Muniz, I.P. (1991). The influence of temperature on aqueous aluminium chemistry and survival of Atlantic salmon (Salmo salar L.) fingerlings. Aquat. Toxicol.,  21, 267-278.

Lydersen, E., Salbu, B., Polèo, A.B.S., and Muniz, I.P. (1991). Formation and dissolution kinetics of Al(OH)3(s) in synthetic freshwater solutions. Water Resour. Res., 27, 351-357.

Lydersen, C. Jensen, P.M. & Lydersen, E. (1990). A survey of the Van Mijen fjord, Svalbard, as habitat for ringed seals, Phoca hispida. Holartic Ecol.,  13, 130-133.

Lydersen, E. (1990). The solubility and hydrolysis of aqueous aluminium hydroxides in dilute fresh waters at different temperatures. Nordic Hydrology,  21, 195-204.

Lydersen, E., Salbu, B., Polèo, A.B.S. and Muniz, I.P. (1990). The influence of temperature on aqueous aluminium chemistry. Water,  Air, Soil Pollut.,  51, 203-215.

Lydersen, E., Polèo, A.B.S., Muniz, I.P., Salbu, B., and Bjørnstad, H. (1990). The effects of naturally occurring high and low molecular weight inorganic and organic species on the yolk-sack larvae of Atlantic salmon (Salmo salar L.) exposed to acidic aluminium-rich lake water. Aquat. Toxicol., 18, 219-230.

Lydersen, E. and Salbu, B. (1990). Studies of aluminium in fresh waters. In : B.J. Mason (ed.) The Surface Waters Acidification Programme (SWAP). Royal Soc. London, Cambridge University Press,  245-250.

Salbu, B., Riise, G., Bjørnstad, H.E. and Lydersen, E. (1990). Intercomparison study on the determination of total  aluminium, and aluminium species in natural fresh  waters. In : B.J. Mason (ed.) The Surface Waters Acidification Programme (SWAP). Royal Soc. London, Cambridge University Press, 251-255.

Salbu, B., Bjørnstad, H.E., Lydersen, E. and Pappas, A.C. (1987). Determination of radionuclides associated with colloids in natural waters. J. Radioanal. Nucl. Chem.,  115, 113-123.

Lydersen, E., Bjørnstad, H.E., Salbu, B. and Pappas, A.C (1987). Trace element speciation in natural waters using hollow-fiber ultrafiltration. In: L. Ladner (ed.) Lecture Notes in Earth Science, Vol.11, Springer-Verlag, Berlin Heidelberg, 85-97.

Salbu, B., Bjørnstad, H.E., Lindstrøm, N.S., Lydersen, E., Brevik, E.M., Rambæk,J.P. & Paus, P.E. (1985). Size fractionation techniques in the determination of elements associated with particulate or colloidal material in natural fresh waters. Talanta, 32,  907-913.