The results of this experiment were similar to other studies which demonstrated that cyanobacteria are more sensitive to H2O2 than green algae and diatoms (Matthijs et al., 2012; Sinha et al., 2018). Cyanobacteria do not produce sufficient enzymes to eliminate reactive oxygen species (ROS) generated after the application of H2O2, causing the oxidation of lipids and proteins in the cells, leading to loss of cellular membrane integrity, inactivation of enzymes, and, ultimately, leading to cell death (Sinha et al., 2018). The main enzymes responsible for ROS degradation are ascorbate peroxidase, not present in cyanobacteria cells, and the haem peroxidase family found only in some cyanobacteria (Bernroitner et al., 2009)