Investigating the trophy condition of Miankala lagoon using TSI and TRIX index

The present study was conducted with the aim of investigating the water quality characteristics and nutritional status of Miankaleh wetland using Carlson Trophy Index (TSI) and TRIX. Measurement of parameters has been done during 6 seasons and 8 sampling periods in 6 stations of Dahane-ye-chopoghli, Bandar-e-Gaz, Gharehsu, Galogah, Ismaeilsay and Miyan ghaleh. Based on the presented results, Dahane-ye-chopoghli, and Gharehsu stations respectively have the highest amounts of phosphate (0.12 mg/l), nitrate (11.04 mg/l), the lowest DO (87 mg/l) and the highest BOD (mg/l 14/77) which indicates the unfavorable condition of the wetland in terms of quality. Calculation of index (TSI) based on (TP) shows that Miankale wetland is in hypertrophic condition (70-80) in four stations and in eutrophic condition (60-70) in Bandar-e-Gaz and Ismaeilsay stations. On the other hand, based on (TN), except for Galogah station,, the rest of the stations are in acute hypertrophic condition (80-100). In general, based on the total TSI index (29.62), the status of the wetland is in the eutrophic range (60-70). The main cause of these conditions is the discharge of sewage and drains from different units on the edge of the lagoon, which contain large amounts of nitrate and phosphate compounds. Therefore, emphasizing the correct and balanced use of chemical fertilizers in accordance with soil needs in order to reduce the load of micronutrient elements should be planned.