SOIL DIATOMS IN SOME AGRICULTURAL LAND OF POTSDAM, GERMANY

The native algal flora of an agricultural soil near Potsdam, Germany, was examined parallel to studies on herbicide influence on soil algae. Soil samples were taken every four to eight weeks from September 1994 to September 1995. Algal densities were determined from cultures on a gar. Cell densities varied between 34,000 and 161,000 cells per g dry weight of soil, of which up to 15.7% were found to be diatoms. Five di atom taxa could be distinguished: Navicula atomus, N. lacunolaciniata, N. cf. mutica, Hantzschia amphioxys and Nitzschia palea. The most abu ndant taxon was Navicula lacunolaciniata, a very small and finely stru ctured species known from highly organically polluted rivers, which ha s not been found in soils before. The other taxa are all known as typi cal soil algae with high tolerance towards nutritional enrichment, esp ecially nitrogen and phosphorus.