利用2015年4~9月对滇池从北到南4个部位的水体水温(Temperature或Temp)、溶解氧(DO)、pH值、叶绿素a(Chl-a)、藻蓝蛋白(Phycocyanin或PC) 和电导率(Conductivity或CD)浓度等监测数据,分析了各参数从旱季向雨季转化以及雨季的特征和空间变化;通过表征蓝藻的藻蓝蛋白浓度和所有藻类的叶绿素浓度之比计算获得了水体中的蓝藻相对数量指数(Cyanophyte Relative Quantity Index, CRQI),并估算了蓝藻在湖泊中的相对数量。结果表明:滇池水温经4~5月增温后在6月达到最高值,之后7~9月在保持一定稳定性的背景下逐步降温,水体温度的变化过程不但会受到水深的影响,表现出在快速升温期不同部位升温速度不同、表层水温快的特点。实测数据分析发现,以叶绿素a值所代表的真核生物在4月快速增加并达到最大值,但以藻蓝蛋白所指示的蓝藻却在9月暴发,这与湖泊表层和底层水温一致、溶解氧含量丰富、pH值达最高并均一及水体盐度较低等因素直接相关。

In order to understand the seasonal change tendencies of the water quality of the Lake Dian (Dianchi), the monitoring data from April to September 2015 at four sites distributed in the central part from North to south were analyzed, these data includes the profiles of the water temperature (Temperature or Temp.), Dissolved Oxygen content (DO), pH values, Chlorophyll-a (Chl-a), Phycocyanin (PC) and Conductivity (CD). At the same time, the Cyanophyte Relative Quantity Index (CRQI) was calculated based on the contents of Phycocyanin and Chlorophyll-a. The results demonstrate that along with the air temperature increase, the water temperature also increased step by step from April and May, and reach the maximum in June, from July to September, the water temperature kept relatively stable and decrease steadily. It also shows that the water temperature is not only various with different water depth, but also show that the temperature increase at different speed, even generally show that the surface temperature increase more rapidly than the deep water. The water temperature and its changes may adjust the air temperature of Kunming strongly and therefore, it is important for the forming of the Four Springs City of Kunming. We found that the amount of eukaryotes represented by Chlorophyll-a increased quickly and reach the highest level in the April, but the blue-green algae, which represented by the Phycocyanin is blooming in the September. This might imply that when the blue-green algae dominated the algae, the algae blooming occur. This is of great importance to understand the algae blooming processes in Lake Dian. We hope the further monitoring will provide us more detailed and useful information. Mean while, the changes of DO, pH and CD all have shown their unique that inspire us to continue the lake water monitoring. This monitoring work also proves that the single site measurements cannot provide any reliable and useful information about the lake water quality. More detailed and sustained monitoring works need to be done before we have a fully understanding on the changes of the lake water quality.