Study On Purification Capacity Of The Emergent Plant Communities In Water Of Taihu Lake

Aquatic plants as an important regulator of the lake ecosystem, play an important role in fixing sediment, preventing sediment resuspension, water purification and so on. Based on the Taihu Lake region, a comprehensive survey conducted on the sample records of plant communities and community structure analysis, and dynamic indicators of water quality and sediment were determined to finalize the advantages of emergent plant communities Phragmites australis and Arundo donax communities in the study.The subject in the middle of the Repulse Bay at Lake Wu set of five samples, statistical aquatic plant species, determination of biomass and community structure of aquatic plants, water quality analysised of pH, turbidity, DO, CODcr, TN, TP and heavy metals, and sediment quality analysis of TN, TP, phosphorus, potassium and heavy metals. Phragmites australis and Arundo donax on water culture were recorded and measured the accumulation of nitrogen and phosphorus, nitrogen and phosphorus removal and phosphorus removal capacity, further study of its water purification capacity.The results showed that the pollution of Taihu Lake area sampling method for the sewage pollution, leading to acidic pH, water, water turbidity increased, the reducing pollution was the main way to pollution, showed a decline in DO and increase of CODcr. The water quality of Phragmites australis and Arundo donax in communities where the plots than other plots have significantly improved.Dynamic indicators of sediment in plots had no significant differences. The one which had an excellent community structure of aquatic plant communities had a significant effect on the absorption on nitrogen and phosphorus content of sediments. It can inhibit the release of sediment nutrients. High nitrogen and phosphorus content of the sediment will stress the growth of aquatic plants, destroyed the aquatic plant community structure.Hydroponic experiment results showed that Phragmites australis and Arundo donax both have a better absorption on nitrogen and phosphorus, but they had no significant effect on the removal of CODcr. Purified from the Comprehensive Evaluation, the purification capacity of Arundo donax better than Phragmites australis, but we also found that Phragmites australis have a higher growth increment than Arundo donax, and had a strong adaptability from the water culture experiments.