香溪河库湾不同季节叶绿素a浓度影响因子分析

Seasonal Distribution of Chlorophyll-a in Xiangxi Bay of Three Gorges Reservoir and Relationship to Environment Factors

研究叶绿素a浓度与环境因子之间的相关关系,为香溪河水质预警、水华防治等水环境保护工作提供科学依据。监测点为香溪河库湾XX06站点,2015年每日1次定点采样,监测指标为氮磷营养盐、叶绿素a浓度、水温、溶解氧、pH、浊度、混合层深度、真光层深度、表底温差、水位及流量等。使用SPSS20.0对环境因子指标和叶绿素a进行person相关性分析。叶绿素a浓度季节性变化显著,夏季最高、春秋季次之、冬季最低,全年平均值为14.38μg/L,变化范围为0.36～108.00μg/L。总氮、总磷和叶绿素a的浓度水平均指示香溪河水体处于富营养化状态。叶绿素a浓度春季与水温、pH、混合层深度正相关,与浊度、总氮、真光层深度负相关;夏季与水温、pH、滞留时间、混合层深度正相关,与总氮负相关;秋季与水温、混合层深度正相关,与浊度、真光层深度负相关;冬季与各环境因子具有一定的相关性,但相关性不显著。

The impoundment of Three Gorges Reservoir drastically altered the hydrodynamics and aquatic environment of reservoir tributaries and algal blooms have become increasingly frequent in the tributary bays. Based on the monitoring data in 2015, the spatial-temporal characteristics of chlorophyll-a （chl-a） and correlations between chl-a concentration and environmental factors were investigated in Xiangxi Bay. The average chl-a concentration was 14.38 μg/L, ranging from 0.36μg/L to 108.00 μg/L. There was an obvious temporal variation in chl-a, with highest concentrations in summer and lowest in the winter. In spring, chl-a concentration was positively correlated with water temperature, pH and mixing depth, and negatively correlated with the turbidity, total nitrogen and eu- phoric depth. In summer, chl-a concentration was positively correlated with water temperature, pH, water retention time and mixing depth, and negatively correlated with the total nitrogen. In autumn, chl-a concentration was posi- tively correlated with water temperature and mixing depth, and negatively correlated with turbidity and euphotic depth. In winter, chl-a did not correlate significantly with environmental factors. The concentrations of total nitrogen, total phosphorus and chlorophyll-a all indicated that Xiangxi Bay was eutrophic.