Abstract
Abstract The spatial distribution of species richness of phytoplankton was studied along the Balkhash Lake water area during the summer of 2004. With statistically weak connections of phytoplankton with environmental parameters, three-dimensional graphs revealed a complex character of its spatial variability in the gradient of environmental factors. Macrophytes had a stimulating effect on the species richness of planktonic algae. We found a correlation between species richness of Cyanobacteria, Chrysophyta, Euglenophyta and Dinophyta and the ionic composition of water. The important role of temperature was traced. Species richness of algal communities increased with increasing temperature in the gradient of nutrients and correlated with the abundance of macrophytes.