太湖水体叶绿素a含量与氮磷浓度的关系

Relationships between chlorophyll-a content and TN and TP concentrations in water bodies of Taihu Lake,China

基于太湖水体1993—2002年5—9月监测资料,进行了叶绿素a含量与总氮(TN)、总磷(TP)浓度关系的分区统计分析,探讨了太湖藻类生长的TN、TP适宜浓度。结果表明:太湖叶绿素a含量与TN、TP浓度的关系存在显著的空间差异;在梅梁湾和西北区,当TN、TP浓度较低时,叶绿素a含量与TN、TP浓度呈正相关;当TN、TP浓度较高时(梅梁湾TN、TP浓度分别超过5.4和0.31mg.L-1;西北区分别超过4.5和0.27mg.L-1),叶绿素a含量与TN、TP浓度呈负相关;在湖心区和贡湖区,叶绿素a含量与TN、TP浓度呈正相关,尤其当TP浓度超过0.1mg.L-1时,叶绿素a含量随TP浓度增加而上升;在东太湖和湖东滨岸区,随TN、TP浓度的升高,叶绿素a含量变化较小;在西南区,叶绿素a含量与TN浓度无显著相关关系,与TP浓度呈正相关;太湖藻类生长的适宜浓度是TN<5.4mg.L-1,TP为0.1～0.31mg.L-1。

Based on the monitoring data from May to September in 1993-2002, this paper studied the relationships between the chlorophyll （Chl-a） content in algae and lower the total nitrogen （TN） and total phosphorus （TP） concentrations in water bodies of Taihu Lake, with the favorable TN and TP concentrations for algae growth discussed. The results showed that the relation-ships between Chl-a content and TN and TP concentrations were quite different in the monitoring zones. The Chl-a content increased with increasing TN and TP concentrations when they were lower than 5.4 and 0. 31 mg · L^-l in Meiliang Bay and lower than 4. 5 and 0. 27 mg · L^-l in the northwest part of the Lake, but decreased with increasing TN and TP concentrations when they were higher than 5.4 and 0. 31 mg· L^-l in Meiliang Bay and higher than 4.5 and 0. 27 mg· L^-1 in the northwest part of the Lake, respectively. In Gonghu Bay and in the central part of the Lake, Chl-a content had positive correlations with TN and TP concentrations, and increased very fast when the TP concentration was higher than 0. 1 mg · L^-1. In Dongtaihu Bay and in the east part of the Lake, Chl-a content varied little with the changes of TN and TP concentrations ; while in the southwest part of the Lake, Chl-a content increased with increasing TP concentration, but had no significant correlation with TN concentration. The favorable water body＇ s TN and TP con-centrations for algae growth in Taihu Lake were 〈 5.4 and 0. 1-0. 31 mg· L^-1. respectively.