Cyanobacterium Microcystis aeruginosa Bloom in Aras Dam Reservoir


1 Iranian Artemia Research Center, P.O.Box 368. Urmia, Iran,

2 Iranian Artemia Research Center, P.O.Box 368. Urmia, Iran

3 Agricultural and Natural resources Research Center of West Azarbaijan, Urmia, Iran

4 Afagh High Education Center, Urmia, Iran


Occurances of cyanobacterial bloom typically appear in eutrophic lakes which either have been
affected by anthropogenic nutrient loading or are naturally rich in nutrients. Microcystis blooms have been reported all over the world in freshwater ecosystems mainly due to increased population which results in increased the waste water production. The aim of this study was to recognize the basic reasons of Microcystis aeruginosa bloom in Aras reservoir. Water temperature, pH, DO, EC, TN, N-No2, N-No3, P-Po4, chl a and the number of Microcystis colonies were determined. The effects of these parameters on the microcystis increased growth was examined. Though we could not strictly relate a few other factors to this phenomenon, higher water temperature, pH and DO in the sampling site i.e. 27° C, 9.16 and 17.2 mg/L respectively, surely favored the M.aeruginosa bloom. In brief, preventing or reducing the nutrients flow into the reservoir should be considered as a priority in order to reduce Microcystis scum forming colonies.