pH值对淡水藻类生长和种类变化的影响

Effects of pH on Growth and Species Changes of Algae in Freshwater

利用水族箱微宇宙研究了淡水藻类在不同pH下的生长和种类变化。结果表明,在pH8.0～pH9.5的范围内,pH8.5下藻类生长状况最好,pH9.5下生长最差;试验范围内蓝藻占绝对优势,但不同处理间种类差别不明显;蓝藻中湖泊鞘丝藻对pH适应范围最广,皮状席藻偏好pH8.5以上的环境;pH8.5的水体固碳能力最强,酸碱度稳定性最高,人为改变pH会使藻类生长受到抑制。

Growth and species changes of algae at different pH values were studied with aquarium microcosms. For the four treatments, pH value in the experimental water was adjusted with either 0.5 mol·L-1 NaOH or 0.5 mol·L-1 HCl every day. The experiment was divided into two phases, the first phase was kept for 30 days, and the second was lasted for 53 days. We have discovered that in the experiment, pH 8.5 was the best optimum value for algae growth, while pH 9.5 was the worst. In the pH range of 8.5 to 9.5, dominant species almost all belonged to cyanophyceae. There was little difference of dominant species among the four treatments. As the main dominant species, Lyngbya limnetica can adapt a wide range of pH value, while Phormidium corium prefers to a pH > 8.5. The capacity of carbon fixation was related closely to pH value of the water. At pH 8.5, the largest amount of inorganic carbon was fixed, while the fixation amount was leastat pH9.5. Carbonate balance in water was often disturbed by absorption of CO2 by algae, thus pH value fluctuates with the growth status of algae. In our experiment, water pH value is stable at 8.5. If the pH value were changed to a level far from the stable value artificially, growth of algae should be inhibited and the algal bloom might be controlled.