Indian Journal of Ecology

Fresh water systems monitoring is the most important issues in Iraq, while it suffers from water shortage and quality altering. The Diyala river is the major tributary of the Tigris river within Diyala Province-Iraq. The physicochemical properties and epipelion community were studied in Diyala River over four seasons. These physicochemical parameters include temperature, light penetration, water flow, electric conductivity (water and sediment), salinity, total dissolved solids, pH(water and sediment), dissolved oxygen, biological oxygen demand, total organic carbon, total nitrogen, total phosphours, and reactive silicate. While the biological parameters were chlorophyll a, phaeophytin a, total number and classification of algae. A total of 182 taxa of epipelion algae was identified. Diatoms were the dominant group of 104 taxa followed by Cyanophyceae (48 taxa), Chlorophyaceae (21 taxa), Euglenophyceae (7 taxa) and Dinophyceae (2 taxa). The higher number of total algae was recorded in the upper reach site (493.96x10³/cm²) while (420.89x10³/cm²) at the middle reach site and (453.45x10³/cm²) in the lower each site. The concentration of chlorophyll-a is ranged from 2.0 mg/dm² to 8.4mg/dm². This study concluded that the water quality of Diyala river was changed and suffered from pollution in terms of Epipelion community.