Mutual Influence of Cyanobacteria and Green Algae in Cocultures Using the Example of <i>Dolichospermum spiroides</i>, <i>Planktothrix agardhii</i>, and <i>Chlorella vulgaris</i>

The excessive intake of biogenic elements into water bodies leads to the active development of planktonic algae, water bloom pathogens, which mostly include cyanobacteria. In vitro studies have allowed us to test a working hypothesis on the absence of any inhibitory effect of metabolites of the Chlorella vulgaris BIN strain on the CALU 799 Dolichospermum spiroides (Klebhan) Wacklin, L. Hoffmann Komárek and CALU 1749 Planktothrix agardhii (Gomont) Anagnostidis Komárek cyanobacterial cultures in working concentrations of 1 : 1, 10 : 1, 100 : 1, and 1000 : 1 (cyanobacteria : chlorella). In a series of experiments, no effect of chlorella culture on the viability of cells of the studied cyanobacteria has been detected. However, high cyanobacteria densities (concentrations of 1 : 1, 10 : 1, 100 : 1, and 1000 : 1) are associated with an increase in the number of dead chlorella cells. The toxic effect of the CALU 799 D. spiroides strain is more pronounced in comparison with that of CALU 1749 Planktothrix agardhii.