铜绿微囊藻生长的营养动力学

应用Monod方程考察氮、磷营养盐对铜绿微囊藻生长的影响.分别计算得到铜绿微囊藻对总磷的半饱和常数Ks_P与对总氮的半饱和常数Ks_N.结果表明:Ks_N>Ks_P,说明总磷对铜绿微囊藻生长的影响大于总氮.铜绿微囊藻的现存量(X)与特定增长率(μ)随着总磷或总氮浓度的升高而升高,但都存在拐点.当总磷或总氮为单一限制性底物时,铜绿微囊藻特定增长率快速增加的总磷与总氮浓度区间分别为:0.005～0.2mg/L与0.01～2mg/L;由于铜绿微囊藻对氮磷亲和力(半饱和常数)的不同,氮磷比对铜绿微囊藻生长的影响并不表现在一个确定值上,也不能用某一确定比例来衡量一个特定水环境中影响铜绿微囊藻生长的限制性营养元素,而应结合氮、磷浓度与氮磷比进行综合考察确定.

Dynamic Studies on the Effect of Nutrients on the Growth of Microcystis aeruginosa

The effects of nitrogen and phosphorus on the growth of Microcystis aeruginosa were investigated by using the Monod equation. The semi-saturation constants of Microcystis aeruginosa to TP (KsP) and TN (KsN) were calculated. The results show that KsN is higher than KsP. This indicates that the effect of TP on the growth of Microcystis aeruginos is further more significant than that of TN. Further analysis finds that extant quantity (X) and special growth rate (micro) of Microcystis aeruginosa increase with TP or TN, and there exists a point of inflection. When the concentrations of TP and TN ranged from 0.005mg/L to 0.2mg/L and from 0.01mg/L to 2mg/L respectively with TP or TN as the single limiting substrate, the growth rate of Microcystis aeruginosa increased rapidly. Because Microcystis aeruginosa exhibits different affinity with TP and TN (according to the semi-saturation constants), the effect of N/P ratio on the growth of Microcystis aeruginosa does not demonstrate at a constant value. No constant ratio can be used to determine the limiting nutrient elements on the growth of Microcystis aeruginosa in any aquatic environment. The effect of N/P ratio on the growth of Microcystis aeruginosa depends on both the N and P concentrations and the N/P ratio.