Ecology, Distribution and Composition of Diatoms in Taleghan Reservoir

Diatoms have been used as important biological indicators of water ecosystems all around the world, mastering and monitoring of their communities are crucial, because some diatom species may cause sudden/severe blooms, also endangering water safety, quality, odor and taste also cause problems for water treatment plants. Taleghan reservoir (Dam Lake) is one of the most important drinking water sources of Tehran, so it is a worthy ecosystem. Mastering domination of Bacillariophytes (Diatoms), species diversity, spatial, temporal dispersions, also some physical, chemical parameters were investigated. Sampling was performed bimonthly, during an annual program, winter of 1393 to winter of 1394, at three stations in three replicates. Based on this study, 20 genus/species were identified. Cyclotella ocellata, Cyclotella antique as centric diatoms and Synedra ulna as pennate diatoms were three dominant species during all sampling periods. Based on these three dominant species, pH (7.4±0.3) and bicarbonate (170±23mg.l-1) Taleghan reservoir was demonstrated to have calcareous basin and slightly alkaline water, based on dbRDA and MDS analysis, the most important influencing factors on the diatom distribution were exhibited depth, SiO2 and HCO32-/PO3-. Also, based on total density of diatoms, this dam lake can be classified as oligotrophic condition.