Auswirkungen von Mischwasserimmissionen auf die Mikroorganismen der heterotrophen Aufwuchsgemeinschaft des Isebekkanals (Hamburg)

AbstractInvestigations of the heterotrophic aufwuchs community on artificial substratum (glass-slides) were conducted in the Isebekkanal (Hamburg) through the seasons from spring to winter in 1997. On principle the poor water quality in the Isebekkanal is influenced by diluted sewage water during heavy rainfalls. According to this the artificial substrates were positioned mediate to the outflows of sewage pipes and allowed to be colonized for 14 days. Variations in the distribution of species are described in respect to sewage effluent. A total of 139 protozoan and metazoan taxa were identified; 55% of the total species number belong to the ciliates. Differences in individual abundances and species diversity were sometimes great, especially after cloud bursts with simultaneous overflows from the sewage system. Similarity between the aufwuchs communities at each station and selected sampling data was calculated (Bray-Curtis-Index). The samples from the dead-end of the Isebekkanal are well separated from those of the mouthregion. The distinct separation of the channel sections is mainly caused by differences in species composition and individual abundances due to the variable high organic loading. On the basis of heterotrophic aufwuchs grown on glass-slides, it is possible to compile reliable information regarding water quality