Abstract
Eutrophication and chemical pollution due to human activities have seriously affected coastal ecosystems during the last three decades. El-Gameel coastal water is one of typical example suffering from such pollution problems. This study was carried out to determine the water quality by studying environmental variables as well as phytoplankton abundance and community structure at five Sites along El-Gameel coast including; El-Gameel airport, El-Gameel inlet, El-Fardous , El-Manasra, and El-Debba. These Sites were under impact of different pollutants due to the domestic and industrial waste effluents discharging. One hundred thirty phytoplankton species were identified from six algal classes. Bacillariophyceae was the most dominant class (75 species, 57.03%), followed by Dinophyceae (20 species, 15.1%), Cyanophyceae (15 species, 12.2%), Chlorophyceae (13 species, 10.2%), Euglenophyceae (4 species, 3.13%) and finally Silicoflagellates (3 species, 2.34%). The results of physico-chemical properties, as well as from predominant high organic tolerant phytoplankton species include Fragilaria construens, Nitzshia closterium, Diatoma vulgares, Oscillatoria spp., Scenedesmus spp. reflect the effect of contaminants on the coast. The highest species richness (90 taxa) was found at El- Gameel inlet (Site II) and the lowest (41 taxa) was recorded at El-Fardous (Site III). Species diversity showed that Sites 1 and V had an average value of 1.6 and 1.97, respectively, indicating moderate pollution, whereas the average values of 1.03, 0.69, and 0.91 at Sites II, III, and IV, respectively, indicating heavy pollution.

Key words: El-Gameel coast, Phytoplankton, Pollution indicators, water quality