穗花狐尾藻和金鱼藻对白洋淀水质影响的原位围隔试验

在白洋淀建成14个原位围隔(9 m2/个),分别按10、20和30株/m2的密度种植穗花狐尾藻、金鱼藻,研究不同密度穗花狐尾藻和金鱼藻在调控水体富营养化方面的效能与稳定性.结果表明:穗花狐尾藻和金鱼藻能有效控制浮游植物的生物量并改善水体SD(透明度),其中密度为10株/m2穗花狐尾藻(平均长度为83 cm,平均湿质量为37.1 g)和密度为20株/m2金鱼藻(平均长度为68 cm,平均湿质量为31.2 g)的围隔控制效果明显,水体中ρ(TN)和ρ(TP)都明显下降,SD增加,浮游植物多样性明显增加,水体营养状态指数(TSIM)明显下降;但高密度沉水植物可能造成水体ρ(Chla)和营养盐含量的反弹.研究证明,种植合理密度的穗花狐尾藻、金鱼藻有利于改善白洋淀水质. 

Situ Enclosure Study on the Effect of Different Planting Densities of Myriophyllum Spicatum and Ceratophyllum Demersum on Water Quality in Baiyangdian Lake

Fourteen situ enclosures(9 m2 each) with different planting densities(10,20 and 30 individual plants/m2) of Myriophyllum spicatum and Ceratophyllum demersum were established to investigate the effects of plant density on control of eutrophication.The results showed that planting Myriophyllum spicatum and Ceratophyllum demersum can effectively decrease the phytoplankton biomass and improve water transparency,especially in the enclosures with 10 plants/m2 of Myriophyllum spicatum(average length 83 cm and average fresh mass 37.1 g) and 20 plants/m2 of Ceratophyllum demersum(average length 68 cm and average fresh mass 31.2 g).In these enclosures,ρ(TN) and ρ(TP) decreased significantly,water transparency and phytoplankton biodiversity increased distinctly,and eutrophication index decreased obviously.However,the submerged macrophytes with high densities could possibly cause the concentrations of chlorophyll a and nutrients to rebound.Therefore,it was concluded that rational density planting of Myriophyllum spicatum and Ceratophyllum demersum could contribute to water quality improvement in Baiyangdian Lake.