Impact of hypolimnetic aeration on abiotic and biotic conditions in a small kettle lake

Abstract

In a small highly eutrophic lake (Weßlinger See, near Munich, F.R. Germany, a hypolimnetic “Limno”; aeration was installed in May 1981. One year before and during the therapy, limnochemical and phytoplankton parameters were recorded twice a month. Chemical parameters indicate a slight but significant reduction of nutrient release from the sediment. Hypolimnetic aeration also increased metalimnetic eddy diffusion of nutrients, especially phosphorus compounds. This internal fertilization increased biomass of filamentous cyanophytes which was recorded by phytoplankton countings rather than by chemical monitoring including pigments.