An introduction to the limnology of the Friesian lakes

Between November 1970 and November 1972 nine sampling trips were carried out in the Friesian Lake District. Fourteen lakes were sampled. The chemical composition of the lake water, chlorophyll-a content and the species composition and population densities of zooplankton and benthos were determined simultaneously. Results are discussed in relation to the hydrology of the Lakes system and the morphometry of the individual lakes. The lakes showed a high degree of similarity.