Study On Common Purification Capacity Of The Aquatic Plant And Communities In Taihu Lake

Based on theTaihu Lake region, a comprehensive survey conducted on the sample recordsof plant communities and community structure analysis, and dynamic indicators of waterquality and sediment were determined. Finally, on the basis of the field survey, Hydroponicexperiments were conducted to investigate ten hydrophytes’ removal effect on nitrogen andphosphorus in eutrophic water, including the dominant species in six plots of Phragmitesperfoliatum, Zizania latifolia, Typha orientalis, Eichhornia crassipes, Potamogetonmalaianus, Ceratophyllum demersum and Lemna minor,combined with the other dominantspecies of Hydrilla verticillata, Vallisneria natans and Pistia stratiote in Taihu basin. The mainfinding are as follows:（1） The major communities in Zhushan lake are growing well, but the single communitystructure are slight, the biomass is still low overall and the level productivity of ecosystemneeds to be improved. From the shore to the lake, the plant species richness index reduced,Shannon-wiener diversity index and Pielou evenness index first decreased then increased, whileSimpson dominance index first increased then decreased.（2） According to the determination of the total nitrogen and total phosphorus content ofeach sampling plot can reflect the presence or absence of aquatic plant and the different aquaticplant community structure have the different nitrogen and phosphorus. In addition, removalcapacities of the life forms of aquatic plant communities are significant difference. Overall,the emergent plant and submerged plants have the better removal capacities.（3） The average total nitrogen content of the sediment is0.874g·kg^-1, and the average totalphosphorus and available phosphorus is5.086g·kg^-1and472.3mg·kg^-1. By contracted thesediment in different community structure, the aquatic plants all have the good removalcapacities, among them Phragmites perfoliatum has the best deposition and removal capacities.（4） Hydroponic experiments Results indicated that all of the ten species showed excellentnitrogen and phosphorus removal capacities. The removal capacities of total nitrogen:Phragmites perfoliatum＞Zizania latifolia＞Vallisneria natans＞Typha orientalis＞Potamogeton malaianus＞Ceratophyllum demersum＞Eichhornia crassipes＞Hydrillaverticillata＞Pistia stratiote＞Lemna minor. The removal capacities of total phosphorus:Vallisneria natans＞Zizania latifolia＞Phragmites perfoliatum＞Ceratophyllum demersum＞Typha orientalis＞Potamogeton malaianus＞Hydrilla verticillata＞Eichhornia crassipes＞Pistia stratiote＞Lemna minor. Overall, the emergent plant and submerged plants have thebetter removal capacities. Therefore，the eutrophication governance in Taihu lake, recovery andreconstruction emergent plant and submerged plants is the effective measure, includingPhragmites perfoliatum, Zizania latifolia, Vallisneria natans, Potamogeton malaianus,Ceratophyllum demersum, et al.