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

Abstract

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.