Affiliations: Department of Desert Studies Center and Sawa Lake, Al-Muthanna University, Samawah, Iraq
| [a] Department of Biology, College of Science, Muthanna University, Samawa, Iraq
Abstract: This study is conducted in order to investigate the trophic state index of Euphrates River flowing through the Samawa city. The present study includes monthly samples collected from three sites (S1: before the Euphrates river enter Samawa center, S2: is located in the Centre of Samawa city, S3: is located at the south of the second site) during the period from April to September, 2020. The study included measurement of some physical and chemical parameters such as Secchi disc, Chlorophyll-a- and total phosphorus. The results showed that TSI (Chl-a) ranging between 4.97-39.39, TSI (SD) ranged between 45.94-81.84, TSI (TP) between 5.81-21.82 and CTSI between 26.18-45.87 with maximum value in September and lowest value in July. The average physiochemical parameters (+-standard deviation) were 7.32 (0.42), 2627.22 (583.94), 5.69 (1.06), 9.5 (3.43), 5.15 (2.05), 1.70 (0.96), 0.57 (0.27), 157.5 (11.69), 1323.88 (259.41), respectively for pH, EC, DO, BOD5, NO3, NO2, PO4, TA, and TDS. Euphrates River is classified as mesotrophic by the CTSI. Statistical analysis showed that positive correlation (p-value 0.01) between the index and (Chl-a-, TP, SD, pH and total alkalinity) while other parameters did not have any correlation with the index. TSI can be used as a baseline for trophic comparisons between the numerous chemical and biological elements of rivers that are connected to trophic status.
Keywords: Carlson’s trophic state index, Secchi disc, total phosphorus, chlorophyll-a, physio-chemical parameters
