Effects of liming on phyto- and zooplankton communities in mountain lakes

摘要

Liming of acidified lakes in Norway has been carried out on a large scale for the last 20 years. The main goal has been to secure the survival and reproduction of fish populations. Effects on whole lake systems have been briefly studied in Norway. Swedish projects however, show a clear increase in both number of phytoplankton species and biomass after liming (Larsson 1995). Later, Persson & Appelberg (2001) showed that after prolonged liming both number and biomass of phytoplankton was lowered and concluded that the long term effect was oligotrophi-cation. The reaction of zooplankton to liming is less clear. Although Degermann et al. (1995) showed that liming usually resulted in increased zooplankton density and biomass, they also found evidence to the contrary.