Interrelations of epibiontic microalgae and crustacean zooplankton under conditions of a blooming eutrophic water body

The possibility of symbiotic, mutualistic (++) interrelations between epibiontic microalgae (Characidiopsis ellipsoidea, Colacium vesiculosum) and cyclopoids (Cyclops vicinus, Mesocyclops leukarti) in the Bugach recreational reservoir with a bloom of cyanobacteria is demonstrated. Overgrown cyclopoids, compared to those free from microalgae, have advantages in oxygen supply, which may be insufficient in the period of intensive algal bloom. Calculations have shown that oxygen requirements of cyclopoids may be fully satisfied due to C. vesiculosum photosynthetic activity in the dysphotic zone if the density of overgrowth exceeds 1000 algal cells per individual. There is no significant correlation between the natural mortality of crustaceans and the indices of their overgrowth by microalgae.