Variations in Nitrate and Phosphate Contents of Waters in the Southwest Caspian Sea

Science and technological developments provide new opportunities to exploit aquatic resource. Hence, it is important to understand biotic and abiotic conditions of aquatic ecosystems. Objective of this Paper is to report findings of the study of nitrate and phosphate contents of water and effects of other physicalchemical parameters in the southwest regions of the Caspian Sea in the spring and summer of 2008. It focuses on the evaluation of nitrate and phosphate concentrations and compares the variations of these parameters with those of previous surveys. Fourty eight Water samples were collected from 18 stations along 6 transects: Astara, Lisar, Anzali, Kiashahr, Chamkhaleh and Chaboksar. Water samples were collected below 10 m depths in western parts of the southern coasts of the Caspian Sea. Temperature, pH and salinity of water were measured and recorded in situ. No significant differences were detected between concentrations of nitrate, phosphate and other parameters studied in the water column at different depths and stations in the six transects. Comparison of results obtained from the present study with those of previous surveys indicated that increasing trends in concentrations of nitrate and phosphate are probably caused by discharge of untreated domestic sewage and the discharge of pesticides from agricultural activities into rivers.