多年生漂浮植物对富营养化水体的响应及净化效果研究

研究了喜旱莲子草、穗状狐尾藻、黄花水龙3种植物在富营养化水体中的生长响应及对水体的净化效果.结果表明,试验确定了穗状狐尾藻最佳生长阈值:N 0.05～0.1 mg/L,P 0.01～0.02 mg/L;黄花水龙:N 0.1～0.2 mg/L,P 0.005～0.01 mg/L.试验结果进一步确定了穗状狐尾藻、黄花水龙阈值氮磷比例范围分别为2 :1～10:1,10: 1～20:1.在试验第35 d时,穗状狐尾藻对总氮、总磷和叶绿素a去除率分别达到了90.5%,88.0%,90.0%,效果最佳;黄花水龙对NO_3~-N、NH_4-N去除效果最好.分别为85.0%,43.5%.对水体中氮的去除主要是微生物和植物吸收共同作用完成.试验进行到35 d时,所用供试植物体内最大积累量占水体初始总氮量的10.36%,仅占水体氮去除的一小部分;通过有植物处理和无植物处理(即对照)对水体中营养盐去除效果的比较得出:3种供试植物对水体氮代谢微生物有正激发效应.而对磷代谢微生物均有负激发效应.

Response and Purification of Perennial Floating Plants in Eutrophic Waterbody

The response to eutrophic water, purification effectiveness of three floating p[ants(Alternanthera philoxeroides, Myriophyllum spicatum, Jussiaea stipulacea) were studied. The thresholds of N, P levels and N/P ratios for the plants to grow were found. The thresholds of N, P levels and N/P ratio for Myriophyllum spicatum, were N 0. 05～0. 1 mg/L, P 0. 01～0. 02 mg/L, and 2 : 1 -10 : 1, respectively. While those for Jussiaea stipulacea Ohwi were N 0. 1～0. 2 mg/L, P 0. 005～0. 01 mg/L, and N/P ratio 10: 1～20:1 respectively. The results showed that Myriophyllum spicatum had a better removal of TN and TP from the eutrophic water, with the removal rates being:TN:90. 5%,TP:88. 0%,Chl -a:90. 0%. Whereas Jussiaea stipulacea had better removal of nitrate and ammonia from the water, with the removal rate being NO_3- N:85. 0% and NH_4-N:43. 5%. The removal of nitrogen were ascribed to interaction of microorganism with plant, as the highest plant accumulation of nitrogen accounted for only 10. 36% of the total concentration of the original eutrophic water body. These three plants had positive effect on the plant-enhanced microbial removal of nitrogen, because the plants had stimulative effect on nitrogen metabolic microorganism. However, the plants had negative effect on phosphorus metabolic microorganisms.