凤眼莲对不同程度富营养化水体氮磷的去除贡献研究

Role of Eichhornia crassipes uptake in the removal of nitrogen and phosphorus from eutrophic waters

  • 摘要: 采用人工模拟方法, 研究了凤眼莲在不同程度富营养化水体中对N、P的吸收和去除作用。结果表明, 凤眼莲在总氮(TN)、总磷(TP)初始浓度分别为2.06~20.08 mg·L-1和0.14~1.43 mg·L-1的4种富营养化水体中均可正常生长, 近1年的试验中, 凤眼莲总生物量累计增加41.03~47.12 kg·m-2, 平均生物量增长率为0.096~0.262 kg·m-2·d-1。凤眼莲地上部N和P平均含量分别为24.16~34.15 mg·g-1和3.46~6.90 mg·g-1; 地下部N和P平均含量分别为11.76~18.45 mg·g-1和6.02~8.50 mg·g-1。凤眼莲在4种富营养化水体中的N和P吸收量累计分别为43.06~71.16 g·m-2和8.68~16.63 g·m-2, 且随水体初始N、P浓度的升高而增加, 并与自身生物量呈极显著正相关(P<0.01)。在N、P负荷较低的水体(Ⅰ和Ⅱ)中, 凤眼莲吸收对N、P的去除贡献均超过100%, 表明凤眼莲吸收利用了底泥中部分N和P; 而在N、P负荷较高的水体(Ⅲ和Ⅳ)中, 凤眼莲吸收对N、P的去除贡献也均超过42.32%和83.79%。因此, 本试验条件下凤眼莲吸收在水体N、P去除中起主要作用。

     

    Abstract: Stimulation experiments were carried out to study nitrogen and phosphorus uptake and removal ability of Eichhornia crassipes from varying degrees of eutrophic waters for the period from Nov. 2007 to Oct. 2008. The results show that E. crassipes grows normally in different degrees of eutrophic waters with initial concentrations of 2.06~20.08 mg·L-1 TN and 0.14~1.43 mg·L-1 TP. Accumulated E. crassipes biomass in eutrophic waters increases by 41.03~47.12 kg·m-2, at a mean growth rate of 0.096~0.262 kg·m-2·d-1 for the period of study. Nitrogen and phosphorus concentrations in E. crassipes aboverground part are 24.16~34.15 mg·g-1 and 3.46~6.90 mg·g-1 respectively. Those in the belowground part are 11.76~18.45 mg·g-1 and 6.02~8.50 mg·g-1 respectively. Total nitrogen and phosphorus uptaken by E. crassipes are 43.06~71.16 g·m-2 and 8.68~16.63 g·m-2 respectively. Meanwhile, accumulated assimilation of nitrogen and phosphorus increases with increasing initial nitrogen and phosphorus concentration in eutrophic waters. There is a significant positive correlation between accumulated nitrogen and phosphorus assimilation with E. crassipes biomass. In eutrophic waters Ⅰ and Ⅱ with lower nitrogen and phosphorus load, contribution of E. crassipes uptake to nitrogen and phosphorus removal is above 100% indicating some uptake of nitrogen and phosphorus from the sediment by E. crassipes. In eutrophic waters Ⅲ and Ⅳ with higher nitrogen and phosphorus load, contribution of E. crassipes uptake to nitrogen and phosphorus removal is above 42.32% and 83.79% respectively. E. crassipes uptake is therefore a major pathway of nitrogen and phosphorus removal in eutrophic waters.

     

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