Environmental and Identification Study of Algae Present in Three Drinking Water Plants located on Tigris River in Baghdad

Planktonic algae dominate the surface of standing waters where light is bright enough for them to produce food by photosynthesis. from September 2011 to August 2012, samples of water were taken monthly from three drinking water treatment stations located on Tigris River in Baghdad City at three sites included river intake, sedimentation tank and walls of sedimentation tank. Seven species of blue-greens were isolated from the river intake of the studied stations which belonged to four cyanobacterial orders: Oscillatoriales, Chroococales, Stigonematales and Nostocales. These genera were dominated in three stations in most of the study period. There were varied results as to the dominancy of algae according to samples collection sites. A total of 268 algal taxa were identified, 161 taxa belonged to Bacillariophyceae (diatoms), 58 taxa to chlorophyceae and 49 taxa to cyanophyceae. The total count of attached cyanophaceae was the hgihest compard with Bacilariophyceae, while total count of cyanophyceae in sedimentation tank was the lowest.