Study on Microscopic Algae in the Iranian waters of the Caspian Sea during 2010-2011

Ongoing study of the Caspian Sea ecology is necessary, particularly identifying the distribution of species, density of biomass, and regional variations in Microscopic Algae. Due to various physical and chemical factors of rivers ended to the sea, and different topography, the initial productions in different seasons are different. The study was conducted during 2010-2011 through spring, summer, autumn and winter, in 32 stations from 8 transects (Astara, Anzali, Sefidrood, Tonekabon, Noshahr, Babolsar and BandarTurkman). In each transect 5 stations in different depths of 5 m, 10 m, 20 m, 50 m and 100 m were defined that the seasonal sampling were performed from the depth of zero (surface), 10 m, 20 m, 50 m and 100 m by Ruttner Water Sampler. Based on the results, 7 branches of Bacillariophyta, Pyrrophyta, Cyanophyta, Chlorophyta, Euglenophyta, Xantophyta, and Chrysophyta and 137 Microscopic Algae species were identified. Among them, 72 species belonged to the Bacillariophyta, 21 species to the Pyrrophyta, 20 species to Cyanophyta, 15 species to Chlorophyta, 7 species of Euglenophyta, 1 species of Chrysophyta, and 1 species of the Xantophyta. The dominant branches of Microscopic Algae were Pyrrophyta, Cyanophyta, and Bacillariophyta, and Shannon index was different for the seasons.