Abstract:

Based on the monthly monitoring data of five samples of water quality in Songya Lake National Wetland Park from June 2018 to May 2019, the spatial and temporal distribution characteristics of water quality in Songya Lake Wetland were analyzed, and the eutrophication status of water quality in this area was evaluated by the modified Carlson trophic state index (TSI). The results showed that: (1) the average content of dissolved oxygen in Songya Lake Wetland was 8.93 mg/L, which was in the oxygen-rich state, and the average pH was 8.2, which was basically weakly alkaline; (2) the average concentration of total nitrogen and total phosphorus was 0.98 mg/L and 0.062 mg/L, respectively, the variation trend of total nitrogen was basically the same as that of ammonia nitrogen, presenting a seasonal variation trend of higher in summer and lower in winter, and there was a large difference in chlorophyll-a concentration among the sampling points; (3) there were differences of the eutrophication status of water quality in the five sampling sites of Songya Lake, the degree of eutrophication from light to heavy was: 2# water management area B< 3# water management area C< 1# wetland water outlet < 4# Reed Square< 5# lake central island, sample 2# showed middle nutrition, while the rest were eutrophication; (4) the seasonal change characteristics of eutrophication status of wetland water quality in Songya Lake were: summer> autumn> winter> spring, and the difference of comprehensive nutritional status index in four seasons was not obvious (P<0.05); (5) the comprehensive nutritional status index of Songya Lake wetland was significantly and positively correlated with DO, pH and TP (P<0.01), and significantly and negatively correlated with Chla (P<0.05), but not with TP and NH₃-N.

Key words: Songya Lake, wetland park, water environmental characteristics, water quality indicators, nutritional status, evaluation of eutrophication