Investigation of the Flora and Diversity of Phytoplanktonic Algae in Yamchi Dam, Ardabil Province

Phytoplanktons are primary producers in aquatic ecosystems, and form part of the basis of the food webs in these ecosystems. Yamchi dam was constructed on Balikhlu River (northwest of Iran). Considering that there was no study of phytoplankton in Yamchi dam, While phytoplanktons are important in understanding the biological function of lakes and detect changes in them, this investigation was carried out to study the floristic composition of phytoplanktons in this lake. In total, 62 Phytoplankton taxa were identified. These belong to 50 genera, 39 families and 9 classes of the algae. Among classes identified in this study, most species were designated to 3 classes: Bacillariophyceae with 23 sp. Chlorophyceae with 12 sp. and Cyanophyceae with 10 sp. Bacillariaceae and Scenedesmaceae each with 6 sp. are the largest families and Nitaschia with 4 sp. is the largest genus identified in the lake, respectively. In the present study, the highest value of diversity was observed in late spring and summer months, which was due to the conditions suitable for growth and co-occurrence of green algae and cyanobacteria, rather than the good quality of water in these months. The lowest values of the diversity index were calculated in the autumn, that the growth condition was suitable for diatoms, with the dominant species of Stephanodiscus neostraea.