Spatial distribution of chlorophyll-a and its relationships with environmental factors in Qinhuai River, Nanjing

近年来,流动的河流开始陆续暴发藻类水华,河流的水华现象是继湖泊水华现象之后又一倍受关注的科学问题.秦淮河水体污染严重并于2010年8月和9月间暴发水华.采用2010年8月15日和9月8日的秦淮河野外调查数据,对秦淮河水体叶绿素a的空间分布特征及其与环境因子的相关关系进行研究.结果表明,从上游到下游,秦淮河水体叶绿素a含量的分布表现出一定的空间差异性,平均值为73.7μg/L,其中马木桥样点的叶绿素a含量最高(184.52μg/L);秦淮河水体氮磷比为26.86,水体叶绿素a浓度的对数与TP的对数呈正相关,与氮磷比的对数呈负相关,表明磷可能是秦淮河蓝藻生长的主要影响因子;河流水体叶绿素a浓度与pH和DO呈极显著正相关,与NO2--N呈显著相关,而与NH4+-N、NO3--N和TN无显著相关.;In recent years, algae bloom is common in the flowing waters, which has been one of the top scientific problems after the algae bloom in lakes. Due to the water pollution, phytoplankton blooms arose in Qinhuai River between August and September, 2010. Based on the conventional monitoring data in August 15 and September 8, 2010, this paper studied the spatial distribution characteristic of chlorophyll-a and its relationships with environmental factors. Results showed that chlorophyll-a concentration appeared obvious spatial difference from upstream to downstream, with a mean value of 73.7 μg/L and the maximum value occurred in Mamuqiao(184.52 μg/L). The ratio of TN/TP was 26.86, and the logarithmic correlation between chlorophyll-a and TP was positive, but the logarithmic correlation between chlorophyll-a and the TN/TP ratio was negative. It suggested that phosphorous might be the main impact factor for blue-green algae. Significantly positive correlation was found between chlorophyll-a and pH and DO, and significantly positive correlation was found between chlorophyll-a and NO2--N, but no significant correlation between chlorophyll-a and NH4+-N, NO3--N and TN.