Investigation of Trophic Status of Kanibarazan Wetland of Mahabad Using Sediment Bioavailable Phosphorous and Carlson Index (TSI)

Kanibarazan wetland is one of the most important satellite wetlands in the South of Lake Urmia, which due to biodiversity; it has been promoted as a wildlife refuge and Ramsar site. In this research, 15 stations were selected in the Kanibrazan wetland of Mahabadfor sampling of water quality parameters in 4 seasons of 2015 and a systematic sampling was carried out. Additionally, 6 bed sediment samples were collected to determine the bioavailable phosphorous content of the wetland during the summer season. Water quality parameters in this study included: nitrogen, phosphorus, transparency, chlorophyll a, biological oxygen demand (BOD), chemical oxygen demand (COD) and bacterial load in the wetland determined by standard laboratory methods. The results for BOD and COD showed that in all seasons the values of these parameters were much higher than the standards. The results also showed that TSI (TNs) was high in the first and second seasons and the increase in TSI (TP) and TSI (SD) values in the autumn and winter seasons were compared to the previous seasons. The average bioavailable phosphorous content in sediment samples was 29.4 mgkg-1 which indicates high risk of the phosphorous release from the bottom sediments to the overlying water and accelerating of the eutrophication process. In addition, the significant (r = 79, P < 0.01) correlation between Colwell-P of sediments and single-cell algae indicated Colwell-P can be used as a bioavailable phosphorous indicator in Kanibrazan wetland. Finally, based on the trophy indices, it was observed that the conditions of the wetland in the spring, summer, autumn and winter seasons are located in the state of Mild Mesotrophic, Oligotrophic, Mesotrophic and Acute Mesotrophic, respectively, and it can be stated that the status of the wetland is passing to the nutritional stage, due to lack of water supply with quantity and quality, especially in summer.