Аннотация:Bioindication, a method for the assessment of the quality of the natural environment with allowance for the state of the biota, is widely used to assess the impact of various factors on an ecosystem. Two problems remain relevant: on the one hand, the adequate selection of biological indicators of the ecosystem state with the greatest bioindicative potential, and, on the other, the establishment of the numerical boundaries of the norm for the indicators. A laboratory algocenosis has been created to study the bioindicational potential of hydrobiological and biophysical indicators. It consists of representatives of various classes of microalgae and cyanobacteria: Anabaena variabilis, Pleurochloris magna, Ankistrodesmus falcatus, and Stichococcus bacillaris. Salts of copper and zinc and diuron were used as effective toxicants. The method of local ecological norms was used for the analysis of the experimental data. The method is based on a computer analysis of the interrelated distribution of biological and physicochemical characteristics, i.e., on the search for boundaries of the factor and indicator norms for which suitable values of the indicator correspond to acceptable values of the factor and unacceptable values of the factor correspond to unsuitable indicator values. The paper analyzes data on 27 bioindicators: various fluorescence indicators, spectral characteristics; number and average volumes of cells of each type; parameters of the rank distribution of the number of species in the sample; evenness indices; nonparametric indices of species diversity; and the phytoplankton saprobity index. The boundaries of each indicator norm have been calculated; the most significant factors, as well as the boundaries of those factors' norm, have been revealed and determined. The bioindicators were compared by the average strength of connection with factors, the number of found significant factors, and their geometric mean value.