沉水植物重建对富营养水体氮磷营养水平的影响

Effects of rehabilitation of submerged macrophytes on nutrient level of a eutrophic lake

利用富营养浅水湖泊 (武汉东湖 )中所建立的大型实验围隔系统 ,研究了沉水植物对水体N、P营养水平的影响 .结果表明 ,沉水植物重建后N、P营养水平显著降低 .在研究期间 ,水生植物围隔总N和总P水平均显著低于对照围隔和大湖水体 ,而且水生植物围隔的总P含量一般维持在 0 .1mg·L- 1 左右 ,季节性波动远低于对照围隔和大湖水体 .水生植物围隔水体中氨态氮和亚硝态氮含量较低 ,而硝态氮含量与对照围隔和和大湖水体差别不大 .由此可见 ,恢复以沉水植物为主的水生植被 ,可以有效地降低N、P营养循环速度 ,控制浮游植物过度增长 。

The effects of rehabilitation of submerged aquatic vegetation on nutrient level of eutrophic waters were investigated by using large scale enclosure system installed in a hyper eutrophicated lake, Lake Donghu of Wuhan. The concentrations of total nitrogen (TN) and total phosphorus (TP) of the enclosures with artificially recovered submerged macrophytes were significantly lower than those of the macrophyte free control enclosure and the lake water, and the TP of macrophyte enclosure was found to be around 0.1 mg·L -1 and relatively stable. The concentration of ammonia and nitrite of the macrophyte enclosures were lower than those of the control and the lake water. However, the nitrate concentrations did not differ among the various water bodies. It was demonstrated that re establishment of submerged macrophytes could efficiently reduce the nutrient level and thus control the overgrowth of the undesirable algae and improve water quality in the eutrophic lakes.