南太湖近岸水域叶绿素a含量与氮磷浓度的关系

2007年6月-2008年4月对南太湖近岸水域进行了4次生态环境调查,在此基础上,对叶绿素a含量（Chl.a）与总氮（TN）、总磷（TP）浓度及氮磷比（N/P）的关系进行了统计分析。结果表明：南太湖水体中Chl.a含量与TN浓度的关系存在显著的季节差异,在蓝藻水华大范围爆发的2007年6月和2008年4月2者呈极显著的正相关,而2007年10月和2008年1月2者无显著性关系;Chl.a含量与TP浓度在4次调查中皆无显著相关关系;岭回归分析显示,N/P 10～25是南太湖水体中附着藻类的最佳生长范围,此时总氮、总磷浓度及氮磷比与Chl.a含量呈显著的正相关,4者的多元回归关系为Chl.a=-0.0012＋0.0064 TN＋0.0215 TP＋0.0005N/P（R=0.543,P〈0.023）。总体来说,南太湖水体中的总氮、总磷浓度及氮磷比皆在藻类生长的适宜范围内,氮磷浓度处于较高水平,已经不是藻类生长的限制因素,在不同水温、光照等环境因子的作用下,加上本水域复杂的水文和季风共同影响下形成了蓝藻水华爆发的季节性差异。

Relationships between Chlorophyll-a Content and TN, TP Concentrations in Coastal Waters of South Taihu Lake

During four cruises conducted from June, 2007 to April, 2008, the relationships between the chlorophyll-a （Chl. a） content and concentrations of total nitrogen （TN）, total phosphorus （TP） and the ratio of TN vs TP （N/P） were investigated. The results showed that both Chl. a content and TN concentration varied significantly in seasons. The Chl. a content had significant relations with the TN concentration during the cyaobacterial boom in June, 2007 and April, 2008, while had no significant relations in October, 2007 and January, 2008. In addition, the Chl. a had no significant relations with the concentrations of TP among the four seasonal cruise investigations, respectively. Using ridge regression analysis method, we found that the optimal ratio of N/P for the growth of cya- obacterial alge ranged from 10 to 25, of which the Chl. a related with TN, TP and N/P significantly, and the multi- ple regression equation was Chl. a = -0. 0012 ＋0. 0064 TN ＋0. 0215 TP ＋0. O005N/P（R =0. 543, P 〈0. 023）. In all, the current concentrations of N and P have positive effect on the algal growth, and neither of them has the potential of being the limited factor for algae bloom. The algae bloom in the south of Taihu Lake may be regulated and controlled by other environmental factors such as water temperature, sun light, hydrological and monsoon. And the seasonal variations of algae bloom could be affected conjunctly by these factors above.