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The World of Protozoa, Rotifera, Nematoda and Oligochaeta

Ref ID : 813

Karl Otto Rothhaupt; A model approach to the population dynamics of the rotifer Brachionus rubens in two-stage chemostat culture. Oecologia (Berlin) 65:252-259, 1985

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A model, based on energy-flow considerations, is presented which describes the population dynamics of Brachionus rubens in the second stage of a two-stage algal-rotifer chemostat. The rotifers are food limited with substrate-inhibition occurring at high algal densities. The model shows two stable states: steady state with constant density of rotifers and washout of the animals. Which one of the stable states is reached depends on the initial conditions. Empirical data are in general agreement with the model. Deviations may be explained by the fact that the data underlying the model calculations are based on a different food alga (Chlorella vulgaris) than the one used in the experiments (Monoraphidium minutum). The observed population growth rate reaches a maximum value of 0.84 (1/day) at algal densities of 3-4x10E6 cells/ml. It decreases at higher algal densities. The egg ratio is related linearly to algal density without being reduced at high algal densities.