浮叶植物重建对富营养化湖泊氮磷营养水平的影响

Effects on nutrient level of a eutrophic lake with reconstructing of floating-leaved aquatic vegetation

利用太湖五里湖污染底泥,在不破坏表层沉积物形态和结构的情况下,利用大口径的采样器采集沉积物柱状样,研究浮叶植物荇菜(Limnanthemun nymphoides)在此底泥上适应性生长情况及其对水体以及沉积物中氮磷的影响.结果表明,在培养实验过程中,荇菜生长使上覆水体中的氮、磷营养水平逐渐降低,藻类的生长明显受到克制,水体透明度增加,水质逐渐改善.通过植物根系对沉积物和间隙水中营养盐的直接吸收,使表层(0～5 cm)沉积物与间隙水中氮磷营养盐的水平在实验结束后有明显下降,对于控制沉积物内源营养盐释放有重要的作用.因此,恢复以水生植物为主的水生生态系统是重建富营养湖泊生态系统和控制湖泊内源负荷的重要措施.

Effect on nitrogen and phosphorus concentration in the overlying water and interstitial water with growing of floating-leaved aquatic vegetation was studie by using intact sediment cores in Lake Taihu of Jiangsu. The result showed that Limnanthemun nymphoides can apparently decrease the concentrations of total nitrogen and total phosphorus in overlying water, control the growth of agal and improve water quality. The nitrogen and phosphorus in the sediments and interstitial water within 5cm depth gradually decreased along with the root system absorption, and nitrogen and phosphorus release were apparent depressed with the Limnanthemun nymphoides growth. So, reestablishment of floating macrophytes was also a significant method to reconstruct the eutrophic lake ecosystem and control inner loading release.