菹草、伊乐藻对沉积物磷形态及其上覆水水质的影响

采集武昌南湖湖水、沉积物进行沉水植物的盆栽试验,试验设置沉积物未施磷处理和施100mg/kg磷处理,分别对应沉积物低内源磷和高内源磷状态,同时种植菹草、伊乐藻,以研究沉积物中磷形态及上覆水水质的变化特点.研究从2007年9月15日开始,历时160d.结果表明,高内源磷沉积物处理后,上覆水中水溶性总磷含量在沉水植物的作用下明显降低;种植沉水植物可使水体总磷、总氮、叶绿素a含量显著降低,且伊乐藻对总磷的净化效果优于菹草;沉水植物对高内源磷沉积物的上覆水中叶绿素a的控制比对低内源磷条件下的效果更好;无论沉积物是否输入磷,在盆栽条件下,上覆水中叶绿素a随时间的变化均能较好地用一级动力学模型来描述;上覆水TDP、TP与沉积物中Ca_(10)-P之间有极显著正相关;种植菹草或伊乐藻的沉积物中Ca_(10)-P与上覆水中TDP和TP的相关系数分别为0.990(P≤0.01)和0.977(P≤0.05).

Effect of Potamogeton crispus and Elodea nuttallii on phosphorus fractionation of sedi-ment and overlying water quality

Using water and sediment of Lake Nanhu, Wuchang of Wuhan City, we designed a group of pot experiments including a control and a treatment that added 100mg/kg phosphorus to the sediment. Submerged macrophytes Potamogeton crispus, Elodea nuttallii were planted in the sediment on September 15, 2007. After 160 days observation, the concentration of the total soluble phosphorus(TDP) in the overlying water responded to the sediment with high phosphorus content and reduced obviously. The treatments all caused total phosphorus(TP) , total nitrogen(TN), and content of chlorophyll-a(Chl. A) in the overlying water obviously reduced. The effect of E. Nuttallii on the total phosphorus was better than that of P. Crispus, and the submerged macrophytes on controlling Chl. A of the overlying water in high phosphorus of the sediments were more efficient than those in the low phosphorus. In the submerged macrophytes cultivation experiment, whether or not applying phosphorus to the sediment the change of Chl. A a- long with cultivated time of the plants could be fitted better with the first order kinetic equation. TDP and TP of overlying water were significantly correlated with Ca-P of sediment, and the correlation coefficient of TDP of overlying water with Ca10-P of sediment under growth of P. Crispus and E. Muttallii was 0.990 (P≤0.01) and 0.977 ( P≤0.05).