Växtplankton i Storvänern 2024

At the beginning of the year the seasonal average biovolumes for 2024 were close to normal levels for the 1979-2024 survey period, although they were lower than in 2023. As usual, the species composition was dominated by diatoms in the lake in April and May, except at Dagskärsgrund, which also had an unusually high proportion of cyanobacteria already in May. In June, the biovolumes varied more between the three sampling sites. At Megrundet, the total biovolume was the highest recorded for the entire lake this sampling season. August biovolumes were higher than the previous year across the entire lake and also higher than the respective period average. Diatoms and chryptophytes dominated throughout the lake. Status assessments of water quality with regard to nutrient impact give a high ecological status for the total biovolume both for the last three years and for the entire period from 1979. The plankton trophic index PTI generally gives a slightly worse status than the total biovolume.