This article presents the results of a study into the species diversity of representatives of the clade Chlorella in Lake Otstoynik (Tolyatti, Samara oblast). This reservoir was used until 1996 for the disposal of nitrogen-tuck production waste but is currently at the stage of self-healing. In the course of the work, 15 strains of microalgae with Chlorella-like morphology were studied. Based on the results of molecular genetic analysis using the internal transcribed spacers ITS1 and ITS2, it was found that only three strains were true representatives of the genus Chlorella. Microalgae from the genera Brachionococcus, Lobosphaeropsis, Micractinium, and Meyerella were also found. In addition, two strains belonged to species that are still formally classified as Chlorella, but their actual taxonomic status needs to be clarified. This study has once again clearly shown that valid identification of Chlorella-like microalgae is not possible using only light microscopy methods. Methods of molecular genetic analysis must be used to study the true species’ richness.
E. S. Krivina (2025) studied this question.