Die tiefenabhängige Entwicklung des Protozoenaufwuchses auf künstlichem Substrat in der Donau I. Die Frage der Tiefenschichtung
[The Protozoa communities on artificial substrates at three levels in the River Danube I. The question of stratification]
Bereczky, Magdolna Cs.; Oertel, Nándor; Nosek, János N.
published: Oct 18, 1983
The Protozoa communities and several physico-chemical variables were studied in the River Danube at Göd (river km. mark 1669, near Budapest) in autumn 1979 and late spring 1980. Samples were taken at three levels (surface, middle and near the bottom) on the 2nd, 4th, 8th, 16th and 32nd days after the exposure of glass slides in metal baskets. Some slides were coated with ovalbumin and some were untreated. The organisms were identified and counted both alive and fixed. Water temperature, dissolved oxygen, conductivity, pH and oxido-reduction potential (ORP) were recorded using a Model 6-D Water Quality Analyser. To evaluate the results, several statistical methods were applied (e.g. Manova, curve fitting, path- and cluster analysis). In the Protozoa community two layers, one near the surface, the other in the water of the middle and lowermost zones, could be distinguished. Certain stratification was established in the physico-chemical parameters too, influenced first of all by stream-flow regime. The highest stratification was indicated in the case of ORP. The stratification of the Protozoa community was influenced by the seasons, too. The layer near the surface seems to be a less stable environment than the lower one.