水华生消模拟及其溶解氧变化过程分析

Simulation for Algal Bloom Occurrence&Disappearance and Its Variation Process of Dissolved Oxygen

分别控制不同初始pH值、水温、光照强度和光照时间等条件,模拟微囊藻水华生消过程。叶绿素a含量变化结果表明:水体初始pH值为8左右时水华暴发强烈,其叶绿素a峰值最高,达199.17 mg/m3;水温高于24℃可促进微囊藻细胞酶活性,使其快速繁殖致水华暴发,叶绿素a峰值超过500 mg/m3;光照强度大、光照时间长的处理组藻细胞光合作用旺盛、水华强烈暴发,其叶绿素a峰值分别为1 065.007 mg/m3和740.561 mg/m3,显著高于其他处理。实验过程中水体溶解氧与叶绿素a含量变化趋势一致,其主要受水华生消过程中藻细胞光合作用产氧影响。基于浮游植物生长动力学的溶解氧动态模型参数拟合结果表明该实验条件下溶解氧预测可用指数模型表达。

Microcystis blooms were simulated in the experiments through controlling the initial pH value, water temperature, illumination intensity and time respectively. Analysis of chlorophyll a concentration showed that when the initial pH value was about 8, Microcystis bloom occurred with the highest peak of chlorophyll a as 199.17 mg/ma. Water temperature higher than 24 ℃ could enhance Microcystis cells to grow fast with strong enzymatic activity, which led to bloom, with the peak of chlorophyll a more than 500 mg/mz. Illumination intensity and time have the similar positive effects on Microcystis growth and bloom; wherein peaks of chlorophyll a are 1 065.007 mg/m3 and 740.561 mg/ma respectively, higher than others. The variation of dissolved oxygen corresponded to that of chlorophyll a in the experiments, which indicated that the dissolved oxygen was mainly affected by photosynthesis of algae. The dynamic model for dissolved oxygen based on the growth kinet- ics of phytoplankton could be displayed by the exponential model, which could he used to forecast the dissolved oxygen.