Liming strategies and effects: the Lake Stora Härsjön case study

The first data available on Lake Stora Härsjön came from the 1930s (Institute of Freshwater Research, Drottningholm) and show that the lake was not affected by acidification at the time. The real documentation of water chemistry and biological conditions in Lake Stora Härsjön began in 1971, when the lake was already severely acidified. The lake was limed in the autumn and winter of 1977/78 and developments since then have been monitored in the form of various study projects. The results, which encompass water chemistry, phytoplankton and zooplankton, benthic fauna and fish, have been presented in a number of reports (Aimer 1972, Dickson et al 1973, Andersson 1977, Alenäs 1979, 1986, Aimer and Hansson 1980, Alenäs et al 1982, Eriksson et al 1983, Hörnström and Ekström 1983, 1986, Hörnström et al 1984, Appelberg et al 1990, Enderlein and Appelberg 1992, Appelberg and Aldén 1992). Lake Stora Härsjon has been part of the ISEL (Integrated Studies on the Effects of Liming) programme since 1989 and reports are submitted annually (Appelberg and Aldén 1992).