阳宗海水质参数季节性变化特征及趋势 Seasonal Variation Characteristics and Trend of Water Quality Parameters in Lake Yangzong

为了解深水型湖泊水质参数的季节性变化特征和水质状况的变化趋势，于2013~2016年不同月份对阳宗海水体水温(Temperature或Temp)、溶解氧(DO)、pH值、电导率(Conductivity或CD)、叶绿素a(Chl-a)和藻蓝蛋白(Phycocyanin或PC)浓度进行连续监测。本文根据监测数据，分析了各参数的时空变化规律；通过表征蓝藻的藻蓝蛋白浓度和表征所有藻类的叶绿素浓度之比求出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：阳宗海春、夏、秋季水温热分层明显，冬季水温混合，湖泊最低温度高于4˚C，属于暖单循环湖；阳宗海水温的分层和混合影响着其他各水质参数的分层和混合，各水质参数的变化趋势基本一致；阳宗海蓝藻相对指数在春、夏、冬季较高，2016年4月年蓝藻相对数量指数高于2015年4月有所升高，尤其是有河流注入的南部湖区大幅升高，表明人类活动对水质恶化有一定的影响；阳宗海电导率的变化受汛期降水的影响较大，电导率较高的季节蓝藻相对数量指数较高，因此电导率可以作为指示淡水湖泊中指示营养状况的指标。 In order to understand the seasonal variation characteristics and trend of water quality parameters in Lake Yangzong, water temperature, dissolved oxygen (DO), pH, conductivity, chlorophyll-a and phycocyanin were monitored from 2013 to 2106 in different seasons. In these parameters, the phycocyanin mainly exists in the cyanobacteria, while Chlorophyll-a is found in all algae. So, the ratio of phycocyanin and chlorophyll-a can be used to represent the relative amount of cyanobacteria in water. Seasonal variation characteristics of water quality parameters and cyanophyte relative quantity index (CRQI) showed that: Lake Yangzong belongs to warm monomictic lakes, the minimum water temperature is higher than 4˚C, thermal stratification phenomenon was observed in spring, summer and autumn, and the water mixed in winter; thermal stratification and mixture had influences on vertical distribution of other water quality parameters, variation trends of all parameters are basically consistent; Cyanophyte Relative Quantity Index (CRQI) in spring, summer and autumn is higher than winter, and increased in April 2016, which was higher than that in April 2015. In particular, there is a sharp increase in the southern region of the lake, where rivers brought a lot of sewage. This indicates that human activities have contributed to the deterioration of water quality.