模拟自然水体中藻-溞-草间的相互作用研究

为了解氮磷浓度对生物操纵效果及同时恢复水生植被的影响,以小球藻、大型溞和金鱼藻分别作为浮游植物、浮游动物和大型沉水植物的代表,模拟自然条件研究了不同氮磷浓度对三者生长和相互作用的影响.结果表明:金鱼藻和小球藻共培养时,在氮浓度介于2.92～12.60mg·L-1、磷浓度介于0.06 ～0.85 mg·L-1,金鱼藻增长不明显,甚至出现负增长；而小球藻的增长率则远高于金鱼藻.小球藻和大型溞共培养时,氮、磷浓度分别为1.26～ 10.53 mg·L-1和0.04～1.16 mg·L-1时均占据优势,对小球藻的抑制效果显著,抑藻及氮磷去除效果明显好于金鱼藻和小球藻共培养,而且磷的去除效果优于氮.三者共培养时,在氮浓度介于3.15 ～23.92 mg·L-1、磷浓度介于0.07 ～0.64 mg·L-1时,大型溞与金鱼藻的增长率都较高,而小球藻则维持在较低的增长水平,水质改善效果较好；当氮、磷浓度分别升至25.95 mg·L-1和1.18 mg·L-1时,大型潘和金鱼藻的增长率均下降,水质变差.大型溞和金鱼藻的联合控藻效果好于其单一的控制效果,该效果明显受到氮磷浓度的影响.

Study on the interactions among Chlorella vulgaris, Daphnia magna and Ceratophyllum demersum in simulated natural water

In order to determine the influences of nitrogen and phosphorus concentrations in the biomanipulation and restoration of aquatic vegetation, Chlorella vulgaris, Daphnia magna and Ceratophyllum demersum, the representative of phytoplankton, zooplankton and submerged macrophyte, were used to study the effects of nitrogen and phosphorus concentration on their growths and interactions in the natural water. The results showed that C. demersum had no obvious growth or negative growth when C. demersum and C. vulgaris were cultured together, and nitrogen and phosphorus concentration ranges were 2.92~12.60 mg·L^-1, 0.06~0.85 mg·L^-1, with C. vulgaris growing better than C. demersum. When D. magna and C. vulgaris were cultured together at nitrogen and phosphorus concentrations of 1.26~10.53 mg·L^-1 and 0.04~1.16 mg·L^-1, respectively. D. magna inhibited the growth of C. vulgaris. The removal rates of nitrogen and phosphorus were greater than those of co-culture of C. demersum and C. vulgaris, and the removal rate of phosphorus was higher than that of nitrogen. When the three organisms were cultured together at nitrogen and phosphorus concentrations of 3.15~23.92 mg·L^-1 and 0.07~0.64 mg·L^-1, respectively, D. magna and C. demersum showed a higher growth rate, while C. vulgaris had a lower growth rate, and the water quality became better. However, when nitrogen and phosphorus concentrations were 25.95 mg·L^-1 and 1.18 mg·L^-1, respectively, their growth rates became lower and the water quality became worse. The combined inhibition of D. magna and C. demersum on C. vulgaris was more effective than the independent inhibition. The effect of algae control was obviously influenced by the concentration of nitrogen and phosphorus in water.