Brit Lisa Skjelkvåle,^* Tom Andersen,^** Eirik Fjeld,^*** Jaakko Mannio,^**** Anders Wilander,^***** Kjell Johansson,^****** Jens Peder Jensen,^******* Tatyana Moiseenko<sup>********


*</sup>Brit Lisa Skjelkvåle is a research scientist and Unit Head (acidification and liming) at the Norwegian Institute for Water Research (NIVA). She holds a PhD in geology from the University of Oslo. Her special interest is effects of air pollution on freshwater acidification. Her address: Norwegian Institute for Water Research, P.O. Box 173 Kjelsås, N-0411 Oslo, Norway. brit.skjelkvaale@niva.no
^**Tom Andersen is a research scientist at the Norwegian Institute for Water Research (NIVA). He holds a PhD in biology from the University of Oslo. His special interest is the application of ecological theory and mathematical/statistical methods in the analysis of field data. His address: Norwegian Institute for Water Research, P.O. Box 173 Kjelsås, N-0411 Oslo, Norway. tom.andersen@niva.no
^***Eirik Fjeld is a research scientist at the Norwegian Institute for Water Research (NIVA). He holds a MSc in freshwater zoology. His special interest is contamination of freshwater ecosystems and fish population ecology. His address: Norwegian Institute for Water Research, P.O. Box 173 Kjelsås, N-0411 Oslo, Norway. eirik.fjeld@niva.no
^****Jaakko Mannio is a research scientist at the Finnish Environment Institute. His special interest is in airborne contamination of upland lakes and catchments. His address: Finnish Environment Institute, P.O. Box 140, FIN-00251 Helsinki, Finland. jaakko.mannio@vyh.fi
^*****Anders Wilander is a senior scientist at the Department of Environmental Assessment at the Swedish University of Agricultural Sciences, Uppsala. He holds a PhD in limnology. His main interest is surface water acidification. His address: Department of Environmental Assessment, SLU, Box 7050, SE-750 07 Uppsala, Sweden. anders.wilander@ma.slu.se
^******Kjell Johansson is professor at the Department of Environmental Assessment at the Swedish University of Agricultural Sciences, Uppsala, and at the Swedish EPA, Stockholm. His main interest is effects of heavy metals on the environment. His address: Dept. of Environmental Assessment, SLU, Box 7050, SE-750 08 Uppsala, Sweden. kjell.johansson@ma.slu.se
^*******Jens Peder Jensen is a senior advisor at the National Environmental Research Institute, Silkeborg, Denmark. His special interest is in the ecology of shallow lakes and freshwater eutrophication. His address: National Environmental Research Institute. Department of Lake and Estuarine Ecology. P.O. Box 314. Vejlsøvei 25, DK-8600 Silkeborg, Denmark. jpj@dmu.dk
^********Tatyana Moiseenko is professor at the Institute of Water Problems in Moscow. Her special interest is problems connected with water resources management and pollution in the Arctic. Her address: Institute of Water Problems, 3 Cenbkina Street, Moscow, Russian Federation. tatyana@iwapr.msk.su