Eco-model based analysis of Lake Taihu cyanobacteria growth factors

Abstract

基于生态模型对2009年4月-2010年11月太湖监测数据进行逐月解析,结果显示太湖蓝藻生长率在时间与空间上都表现出显著的差异性,1-4月及10-12月蓝藻生长率表现为低水平,6-9月为高水平,5月年际差异较大,湖西岸相对于湖中区蓝藻生长率优势较明显,水面至水深1 m之间为蓝藻生长活跃区域.蓝藻的生长与消亡主要受水温、光照、磷三种影响因子控制,这三种因子表现出较明显的季节性特点,并且对蓝藻生长率的影响具有相互交替作用的动态变化特征,其中水面附近为温度及磷限制,水深0.5 m处为温度、磷及光限制交替作用,水深1 m及以下为光限制.计算结果表明在研究时段内营养盐总体表现为磷限制,夏秋季局部水域也存在氮限制.;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.