干旱季节水库水质pH值增高原因探析

Expiore the Uprising of pH Value in Lake Water on Dry Season

随着水库蓄水量的减少,水生生物快速大量生长,破坏了水体中碳酸氢盐的水解平衡,伴随生物利用水中二氧化碳进行光合作用的过程,水中氢氧根离子含量增加,氢氧根离子又使碳酸氢根的电离平衡向生成碳酸根离子方向移动,导致水中碳酸根离子浓度增大,总碱度增加,同时湖库底质盐碱土和草甸土的碳酸氢盐以及碳酸盐的平衡释放也使水体的碳酸氢盐得到外源补充。周而复始使水体的碳酸盐碱度和总碱度不断增加,pH也逐步增高。在相对往年引入嫩江水容量较少的情况下,干旱、高温、少雨、水体表面的物理蒸发和生物蒸腾作用,水库水容量急剧减少,上述情况进一步加剧。并通过对水库出口的碱度进行修正,推算出水体的生物量,和理论生物量计算值相符合。

Along with the capacity of reservoir reducing, a large number aquatic organisms grow up quickly, and then they destroy the hydrolysis equilibrium of bicarbonate salt. With the process of organisms using CO2 photosynthesis, the hydroxide ion of water have been increasing. And the hydroxide ion make ionization equilibrium of bicarbonate progress toward producing carbonate, then result in the concentration of carbonate ion and total alkaline increasing. At the same time the equilibrium releasing of bicarbonate salt and carbonate in reservoir sediment saline - alkali soil and meadow soil make replenish bicarbonate salt by for- eign aid, once again make the concentration of carbonate ion and total alkaline increase, pH value uprise step by step. Under this circumstance of diversion capacity of Nenjiang River is little opposite to past years, dry, high temperature, few rain, physics yap- orate of water surface and organism＇s transpiration, the capacity of reservoir reduces rapidly, above - mentioned conditions further aggravate aspect. After alkaline of reservoir＇s outlets have been corrected, the calculated biomass of reservoir＇s water body which are in good agreement with the theoretical results.