Vergleichende untersuchung des peptonabbaus und der damit verknüpften ciliatenbesiedlung in strömenden und stagnierenden modellgewässern

Summary The decomposition of peptone and the associated species numbers and individual counts of ciliates has been investigated in flowing (current speed 40 cm/sec) and stagnant model ecosystems. In order to imitate the ecological conditions in natural waters receiving sewage small quantities of peptone were added at regular intervals.The most important environmental factors such as pH, dissolved oxygen, NH₄ ⁺-, NO₃ ^--levels, and the organisms occurring in the free water as well as in the periphyton community on microscopic slides, were investigated for three weeks. Both the population dynamics of organisms and the environmental conditions within the ecosystems are figured (Figs. 1–6).The ecosystem with flowing water, and the aerated stagnant model showed high contents of O₂ and fast mineralisation of peptone up to the NO₃ ^--level. The unaerated model showed a retarded decomposition of peptone and accumulation of ammonia.The unaerated stagnant ecosystem showed the highest individual counts of bacteria and ciliates, while in the flowing model a limited number of organisms only was found.Most of the differences between flowing and stagnant waters are due to the varying O₂-level. Only two species were directly inhibited by the current speed tested in these experiments.

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Zoologisches Institut der Universität Bonn Hydrobiologische Arbeitsgruppe (Leiter: Prof. Dr. H. Bick)

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Mit Untersützung der Weltgesundheitsorganisation.

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Herrn Prof. Dr. Rolf Danneel zum 70. Geburtstag gewidmet.

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Anschrift der Verfasser: PProf. Dr. H. Bick und Diol. Biol. W. Schmerenbeck, Hydrobiologische Arbeitsgruppe am Zoologischen Institut der Universität, D05300 Bonn 1, Poppelsdorfer Schlo\.