氯化物水型盐碱池塘缓冲能力研究

Study on buffer capacity of water (Cl_Ⅱ^(Na) and Cl_Ⅱ^(Na) )in saline-alkaline pond

用生氧量生物测验法对 4口缓冲物质含量不同的氯化物水型 (ClⅡNa)盐碱池塘水的缓冲能力进行研究。结果表明 ,浮游植物的光合作用 (净产氧量 )与池水 pH升高密切相关。这类盐碱池塘 pH较高的原因是总CO2 或Ca2 + 含量相对较低所致 ,向池水中添加相对缺乏的缓冲物质可大幅度地减小光合作用引起的 pH的上升。当池水中总CO2 含量相对不足时 ,通入CO2 比加入含HCO3- 的缓冲溶液能更有效地提高其缓冲能力。文中拟合了不同缓冲剂含量的池塘水中由于光合作用所引起的OH- 增量与总CO2 和Ca2 + 浓度之间的回归模型。还探讨了池塘水的 pH与总CO2 、Ca2 + 浓度和浮游植物密度的相互关系 。

The experiment was conducted with 4 ponds (Cl Ⅱ Na ) in June, July and August, 1997. The results show that the increase of [OH -] (or pH value) in pond water correlated closely with the photosynthesis rate of photoplankton; the buffer capacity was controlled by the concentrations of total CO 2 and Ca 2+ ; the increment of pH value caused by photosynthesis was greatly reduced by adding a certain kind of buffer, which was relatively deficient, into pond water. When total CO 2(or ALK) content was relatively lower,mixing CO 2 into water was more effective to promote the water buffer capacity than adding HCO 3 -. The reason why pH values of pond water in saline-alkaline land were relatively higher was that the content of total CO 2 or Ca 2+ was too lower. A multiple regression was developed to simulate the relationship between the increment of[OH -] based on the same photosynthesis rate and [Ca 2+ ] or total CO 2 in pond water. Also a similar model was developed to simulate the relationship among the pH value,the contents of Ca 2+ or total CO 2 and the relative biomass of algae (as absorbance at 400 nm wave length with 3cm cell).