REMOVAL EFFICIENCY OF PHOSPHORUS IN HYPERTROPHIC LAKE DONGHU WATER BY COMMON SUBMERGED MACROPHYTES

With an artificial imitation,five dominant hydrophytes,Ceratophyllum demersum,Elodea canadensis,Potamogeton crispus,Myriophyllum spicatum and Vallisneria spiralis,were used to investigate removal efficiency of phosphorus in hypertrophic Lake Donghu water at different weather conditions.The results showed that all the submerged macrophytes grew well and the growth rate of Ceratophyllum demersum,with 128.88%,58.33% in the Spring and Summer experiment respectively,was the highest.And all the submerged macrophytes absorbed total phosphorous in water effectively and the removal rate of Ceratophyllum demersum with 91.75%,92.44% in the Spring and Summer experiment respectively,was the best.At the same time,these submerged macrophytes can maintain the concentrations of various phosphorus forms in low levels,mainly by uptaking the phosphorus from overlying water and inactivating the release of phosphorus in the sediment.In conclusion,Ceratophyllum demersum could remove the phosphorus from hypertrophic water effectually and grow well.Also,with high tolerance of contamination it may be used as one of the pioneer species for macrophyte recovery in hypertrophic shallow lakes.