Correlation between chlorophyll-a concentration and environmental factors in shallow lakes in plain river network areas of Suzhou

运用回归统计方法,研究苏州平原河网区60个浅水湖泊水体叶绿素a与水温、pH、DO、CODMn、TN、TP等环境因子的相关性,建立相应的回归方程,同时分析了湖泊水体叶绿素a的时空分布特征.研究表明,平原河网区浅水湖泊水体叶绿素a含量具有一定的时空差异性,冬季叶绿素a平均含量比夏季低,但冬、夏季叶绿素a含量空间分布具有一定相似性,整个区域呈现较明显的东高西低的分布趋势;湖泊水体叶绿素a含量与理化环境因子水温、pH、DO、CODMn呈显著正相关,水温可能是平原河网区浅水湖泊浮游植物生长的限制性因子;叶绿素a与NO2--N呈显著正相关,与NH4+-N无明显负相关,与NO3--N无显著正相关,与TN无显著相关,而叶绿素a的对数与TP的对数呈一定的正相关,与TN/TP的对数呈显著负相关,平原河网区浅水湖泊可能是一定程度的磷限制性湖泊.;The correlation between chlorophyll-a concentration and some environmental factors (water temperature, pH, DO, CODMn, TN and TP) in sixty shallow lakes in plain river network areas of Suzhou was studied by regression statistical method, and the spatial and temporal distribution characteristics of chlorophyll-a were also analyzed. The results indicated that there were some differences in the spatial and temporal distribution of chlorophyll-a in shallow lakes. In winter, the average concentration of chlorophyll-a was lower than that in summer. The temporal distribution of chlorophyll-a in winter and summer also had some similar pattern decreasing from east to west. Significantly positive correlations were found between chlorophyll-a concentration and water temperature, pH, dissolved oxygen, permanganate indexes. Water temperature was possibly the main limited factor of phytoplankton growth. At the same time, significantly positive correlation was found between chlorophyll-a and nitrite nitrogen, but not for ammonia nitrogen, nitrate nitrogen, total nitrogen. However, positive logarithmic correlation was found between chlorophyll-a and total phosphorus, and negative logarithmic correlation was found between chlorophyll-a and the ratio of total nitrogen to total phosphorus. The results suggestted that phosphorus might be the limited factot in the shallow lakes to some extent.