Phytoplankton from Swedish lakes EL Lake Assjön 1961-1962.

Quantitative and qualitative analyses of phytoplankton in Lake Assjön, southern Sweden, were carried out during the period May 1961 to July 1962, incl. Some physical and chemical data from the period are given. The list of species includes ca. 100 taxa dominated by the group Chrysophyceae. The total volume of phytoplankton was low throughout the period: only once a value of 400 ∙ 10⁶μ3/1 was exceeded. This was obtained in July when Dinobryon spp. and small flagellates predominated. In the spring of 1961 relatively high volumes of diatoms were recorded. As to total volumes some comparisons were made with corresponding values from Lake Vättern and from some lakes within the drainage area of Lake Mälaren. The phytoplankton of Lake Assjön is also compared with that of Lake Södra Vixen which has about the same trophic level. Comparisons were also made with data from six other lakes situated close to Lake Assjön: all these lakes were investigated in May 1961. The total phytoplankton volume in lakes of the type described in this paper exceeds a value of 1,000 ∙ 10⁶μ3/1 (1 mm3/1); as a rule values lower than 500 ∙ 10⁶μ3/1 are obtained. [ABSTRACT FROM AUTHOR]