广东省公平水库与星湖生态特征的对比分析

Comparison of ecological characteristics between Gongping Reservoir and Xinhu Lake,Guangdong Province

在采样和测定分析的基础上,对营养盐水平和水深较为接近的公平水库和星湖的生态特征进行对比分析。结果表明,公平水库和星湖的生态特征差异显著,其主要原因是两者水动力过程的不同。公平水库水力滞留时间是星湖的1/2,水柱全年混合较好,而星湖在夏季则有明显分层现象。公平水库总氮、总磷浓度的最高值出现在丰水期的7月,枯水期明显低于丰水期,营养盐主要来源于外源,而星湖主要受内源循环的控制,总氮和总磷浓度的最高值出现在丰水期刚开始的4月,7月总氮、总磷浓度有所下降,在分层现象消失的10月,总磷浓度明显升高。公平水库水滞留时间短,水位波动较大,不利于蓝藻形成优势,其浮游植物的群落结构类型表现为硅藻绿藻蓝藻型,星湖水滞留时间长,水体相对稳定,为蓝藻占优势提供了条件,浮游植物群落结构类型表现为蓝藻绿藻硅藻型。

Based on sampling and analysis of ecological Characteristics,we compared the physical factors,nutrients and phytoplankton structure of Gongping Reservoir and Xing Lake,which were similar in trophic level and water depth.The results suggested that there were significant differences in ecological processes between the reservoir and the lake,which was mainly attributed to the difference in hydrodynamics.The water retention time at Gongping Reservoir was half of that at Xing Lake,and the water column of Gongping Reservoir was well mixed over the year,while Xing Lake was stratified in summer.The nutrient concentration in Gongping Reservoir,which was affected mostly by watershed inputs,was higher in flooding season than in dry season, with highest value occurred in July.However,in Xing Lake,affected mostly by inter-cycle,the nutrient concentrations were high near the end of the dry season,but fell in July and the concentration of TP went up when the stratification disappear.The difference of retention time also resulted in different dominant phytoplankton groups.Xing Lake was dominated by Cyanobacteria for its longer retention time and steady water column,while Gongping Reservoir was dominated by Bacillariophyta.