Population structure study of Anzali wetland phytoplankton

Phytoplankton groups are very important producers in the Anzali lagoon that have a significant role in the quality of water and the need to be constantly study their sequence and density. The survey was conducted in six workstations March 1389-Feb 2012. Samples were taken for a liter of water with plicae (P.V.C) and fixed with formalin to 4% ratio. Five ml of the sample after becoming homogeneous, was sequestration for 24 hours in the laboratory and identified and counted by invert microscope. Based on the results of this reviews 67 genus (22, 26, 9, 5, 1, 2, 1, and 1 genus respectively of the Bacillariophyta, Chlorophyta, Cyanophyta branches, Cryptophyta, Euglenophyta Chrysophyta, Pyrrophyta, the Xanthophyta) were identified. The results showed that the phytoplankton density was the most in Sorkhankol and Komeh Aghajani stations with annual average of 24387483±5643414 and 20381250 ± 5488084 per liter respectively. The Bacillariophyta ( particularly Cyclotella) was dominant in all of stations but high density of blue green algae (Cyanophyta) in Komeh aghajani station from July to mid-October have caused the annual average of these phylum is more than Bacillariophyta. In General, the average density of phytoplankton was the highest in summer than other seasons and was the lowest value in the fall. The number of the genus identified in this survey is less than previous studies. Compare this survey with the last studies reviews shows that diversity is reduced in the current situation in the Anzali than previous studies. According to the statistical analysis of the Kruskal Wallis, the density of phytoplankton had no significant differences in the different months, stations and seasons (p>0.05) but the phytoplankton phylums have significant differences (p