Population ecology of rotifers as a bioassay tool for ecotoxicological tests in aquatic environments.

The population dynamics of the monogonont rotifer Brachionus rubens were used under controlled experimental conditions as a sensitive bioassay for toxic substances in sublethal doses. Even slight reductions in organism fertility and life expectancy were reflected at the integrated level of population dynamics. Serving as bioindicators for the standard test are the population parameters "intrinsic rate of natural increase" (r), "carrying capacity" (k), "frequency" (f), and "pregnancy" of the density oscillations (p). The optimal spreading power (steepest slope of the response curves) lies at different concentration areas for each parameter, so that they can be used specifically in standard tests.