This study examines the relationship between phytoplankton population and some important physicochemical variables in the Bukan Dam Reservoir. The sampling was performed monthly from 8 sampling sites from April 2008 to February 2009. Phytoplankton counts were made by inverted microscope. | Research Article Turk J Bot 35 (2011) 77-84 © TÜBİTAK doi: Seasonal changes in phytoplankton community structure in relation to physico-chemical factors in Bukan dam reservoir (northwest Iran) Ali MOHSENPOUR AZARI1,3, Fereidun MOHEBBI1, Alireza ASEM2,4 1 Iranian Artemia Research Center, 368, Urmia - IRAN 2Fisheries Department, Afagh High Education Center, Urmia - IRAN 3Student of Department of Invertebrates, Faculty of Zoology, University of Baku - AZARBAIJAN 4Protectors of Urmia Lake National Park (NGO), Urmia - IRAN Received: Accepted: Abstract: This study examines the relationship between phytoplankton population and some important physicochemical variables in the Bukan Dam Reservoir. The sampling was performed monthly from 8 sampling sites from April 2008 to February 2009. Phytoplankton counts were made by inverted microscope. Totally, 55 phytoplankton taxa were identified and included Chlorophyta, Bacillariophyta, Dinophyta, Cyanobacteria, Euglenophyta, Chrysophyta and Cryptophyta. Correlations between some important physicochemical factors and total phytoplankton number were calculated. Results 2 indicated that phytoplankton total number positively correlated with NH3 (R = ) and negatively correlated with 2 Secchi disc depth (R = ). Key words: Iran, Bukan, reservoir, phytoplankton, physicochemical factors Introduction One of the most important living organisms in the aquatic ecosystem is phytoplankton. Phytoplankton, the primary producer, plays an important role in the material circulation and energy flow in the aquatic ecosystem. Its presence often controls the growth, reproduction capacity, and population characteristics of other aquatic organisms (Ariyadej et al., 2008). Changes in the phytoplankton of freshwater lakes have long been recognised as providing a good indicator of the trophic status and environmental quality of the system (Reynolds, 1996). Increased growth of certain groups of
