夏季香溪河库湾溶解氧与叶绿素a日间垂向分布特征及影响因子初探

Vertical Distribution of Dissolved Oxygen and Chlorophyll-a and Its Influencing Factors in Xiangxi River Reservoir Bay in Summer

为了解三峡水库水华爆发时空特征,于2020年6月在三峡库区香溪河库湾未发生水华的条件下通过日间高频次连续加密监测,分析溶解氧、叶绿素a等指标的时空变化,甄别藻类生长特性。结果表明,温跃层和表中层倒灌异重流的存在阻碍了垂向水动力交换,进而促使水体表底均存在氧跃层;夏季连续的晴天可能会导致07:00~11:00、14:00~17:00爆发水华的几率增加;水华爆发存在滞后性,仅通过单层水体藻密度无法表征藻类生长状况,需通过藻类垂向迁移范围内的平均藻密度作进一步水华预警判断。

In order to understand the temporal and spatial characteristics of blooms in the Three Gorges Reservoir,the temporal and spatial changes of dissolved oxygen,Chlorophyll-a and other indicators were analyzed,and the growth characteristics of algae was screened,which can provide reference for the early warning of blooms under the condition that no blooms occurred in Xiangxi River bay of the Three Gorges Reservoir in June 2020.The results show that the thermocline and the surface layer of the inverted weight current block the vertical hydrodynamic exchange,and then promote the presence of oxygen thermocline at the bottom of the water surface.Consecutive sunny days in summer may increase the chance of bloom outbreaks from 7:00 to 11:00 and from 14:00 to 17:00.There is a lag in bloom outbreak.Algae growth cannot be characterized only by the density of algae in monolayer water,so it is necessary to use the average density of algae in the vertical migration range for further bloom warning.