Eco-model based analysis of Lake Taihu cyanobacteria growth factors

Based on an eco-model,we analyzed the monthly monitoring data of Lake Taihu from April 2009 to November 2010,and found that the growth rates of Lake Taihu cyanobacteria showed significant both temporal and spatial differences.The growth rates of cyanobacteria were low from January to April,and from October to December,while high level from June to September.But the growth rates in May showed annual difference.Furthermore,the growth rates in western lakeshore were higher than those in the central lake.The growth of cyanobacteria from surface water to one-meter depth was active.Growth of cyanobacteria was mainly controlled by water temperature,illumination and phosphorus concentration.These three limiting factors showed significant seasonal variation and interchanged with the others.In the surface water,temperature and phosphorus were the main limiting factors,while temperature,phosphorus and illumination at the depth of half a meter,and illumination below one-meter depth.The result showed that phosphorus concentration in summer and fall was the major limit on nutrient phosphorus,and also limit on nitrogen in some areas.