Investigation the effect of microalgae and cyanobacteria exposed to different stress conditions (Salt Lake Basin, Turkey) on the growth performance of Daphnia magna

In this study, the changes in the biochemical composition of Phormidium lucidum isolated from the water samples taken from Lake Bolluk (Salt Lake Basin, Turkey) to be used as an alternative to the nutrients used in the development of Daphnia magna and its effect on the development and growth performance of Daphnia magna were investigated. In order to determine the changes in the biochemical composition of Phormidium lucidum under different stress conditions, experiments were carried out on BG11 media prepared at different pH values (7.18, 8.15, 9.17 and 10.26), temperatures (10, 20, 25 and 30 oC), light intensity (1200, 2400, 3600 and 4800 lux) and nitrogen concentrations (0.25, 0.5, 1.0 and 1.5 g/L). At the end of the 2-week incubation period for Phormidium lucidum, the ideal stress condition was determined to be pH 7.18, 20 oC, 3600 lux and 0.25 N medium by measuring the total protein, total lipid and chlorophyll-a amount. In the study, fatty acid profile analysis of Phormidium lucidum developed in a medium containing pH 7.18, 20 oC, 3600 lux and 0.25 N was performed. In order to determine the effect of nutrient composition on optimum growth rates of Daphnia magna, five different food groups containing various concentrations of Chlorella vulgaris and Phormidium lucidum were prepared in groups of three. The best growth rate for Daphnia magna was obtained at the end of the 13th day in the medium containing 100% Phormidium lucidum. The results of this study revealed that Phormidium lucidum can be used as an alternative to foods such as bacteria, yeast and commercial feeds used for Daphnia magna.