4种水生植物除磷效果及系统磷迁移规律研究

Research on removal efficiency of phosphorus by four aquatic macrophytes and rule of phosphorus migration in systems

[目的]研究不同生态类型水生植物对水体总磷的去除效果及系统磷迁移规律。[方法]选取4种不同生态类型水生植物,分别为漂浮植物凤眼莲、水浮莲和挺水植物香蒲以及沉水植物轮叶黑藻,结合滇池富营养化湖水及底泥,构建静态模拟生长体系。[结果]4种水生植物对富营养化湖水、底泥具有一定的耐受能力。试验80 d后,凤眼莲、水浮莲和香蒲对水体总磷的去除率分别为95.0%、94.3%和92.0%。凤眼莲系统中水体磷浓度大幅度降低,底泥中的磷素逐渐释放,凤眼莲所吸收磷素来源于水体和底泥;水浮莲所吸收磷素主要来源于水体;香蒲鲜质量增加极少,在降低水体总磷浓度的同时,促使底泥总磷含量略微增加,从表观上看,水体为其吸收磷素的主要来源;轮叶黑藻植株部分发生腐烂,对水体总磷的去除率仅为62.9%,低于对照,但对底泥中总磷吸收良好,底泥是其吸收磷素的主要来源。[结论]凤眼莲、水浮莲和香蒲能有效降低水体总磷;凤眼莲和轮叶黑藻能够吸收底泥中的磷素;当水体总磷浓度较低时,底泥中的磷素会释放至水中。

[Objectives]Removal efficiency of phosphorus by aquatic macrophytes of different ecological types and rule of phosphorus migration in the systems were discussed in the paper. [Methods]Static simulation experiments were carried out utilizing eutrophic water and sediment from the Dianchi Lake together with four aquatic macrophytes of different ecological types,including the floating plants water hyacinth and water lettuce,the emergent plant typha and the submerged plant hydrilla. [Results]The four water macrophytes showed considerable tolerance capacity to eutrophic water and sediment. After 80 days,the removal rate of total phosphorus（ TP） in water were 95. 0%,94. 3% and 92. 0% respectively. In water hyacinth system,while the concentration of TP in water significantly decreased,the phosphorus in sediment gradually released,so phosphorus absorbed by water hyacinth came from water and sediment. In water lettuce system,the main source of phosphorus absorbed by the plant was water. In typha system,though the plant biomass increased very little,the plant also reduced the concentration of TP in water and prompted a slight increase of phosphorus content in sediment,and then,from the table new phosphorus absorbed by the plant mainly came from water. In hydrilla system,due to part rot of the plant,the removal rate of TP in water was 62.9% below the control treatment,but the plant showed a good absorption capacity to phosphorus in sediment,so sediment was the main source of phosphorus absorbed by the plant. [Conclusions]Water hyacinth,water lettuce and typha could effectively reduce the concentration of total phosphorus; water hyacinth and hydrilla could assimilate phosphorus in sediment. When the concentration of total phosphorus in water was low,the phosphorus in sediment could release to the water.