巢湖叶绿素a浓度的时空分布及其与氮、磷浓度关系

摘要

基于巢湖水体2002～2007年水质监测资料,对叶绿素a浓度的分布、动态及与TN、TP的关系进行了统计分析.巢湖叶绿素a浓度与TN、TP的浓度分布存在明显的空间差异,西半湖叶绿素a浓度全年高于20μg/L,TN为1.94～3.84mg/L,TP为0.20～0.42mg/L;东半湖叶绿素a浓度全年小于5.5μg/L,TN为0.95～1.83mg/L,TP为0.08～0.14mg/L.在东半湖,叶绿素a含量与TN呈不明显的正线性关系,当TP浓度较低时,叶绿素a随TP的增加小幅上升,但是当TP>0.15mg/L时,叶绿素a随TP的增加而明显上升;在西半湖,当水体TN<5.8mg/L或者TP<2.0mg/L时,叶绿素a含量与TN、TP关系为正线性关系,当TN在5.8～9.4mg/L或者TP介于0.2～0.3mg/L间时,叶绿素a含量与TN、TP关系为不显著的负线性关系,当TP浓度>0.3mg/L时,叶绿素a含量与TP关系又为正线性关系.西半湖叶绿素a浓度的变化可能是藻类生物活动与沉积物及水体中营养盐的相互作用结果.在治理巢湖富营养化时,应优先控制西半湖的磷元素.%Based on the monthly monitoring data in 2002 -2007 , the spatial and temporal dynamics of chlorophyll a ( Chl - a) concentrations and its relationships with total nitrogen (TN) and total phosphorus (TP) concentrations in water bodies of lake Chaohu were studied. The results showed that parameters like Chl-a content , TN and TP concentrations were quite different in the monitoring zones.In the westem area of the lake, the content of Chl-a was above 20μg/L all the year, and concentrations of TN and TP were 1. 94 -3. 84 and 0. 20 - 0. 42mg/L, respectively. While in the eastem area of the lake , the content of Chl-a was below 5. 5μg/L all the year,and concentrations of TN and TP were 0. 95 - 1. 83 and 0. 08 - 0. 14mg/L, respectively. In the eastem area of the lake, Chl-a content had positive correlations with TN and TP concentrations , and increased very fast when the TP concentration was above 0. 15mg/L. The Chl-a content increased with increasing of TN and TP concentrations when they were below 5. 8 and 0. 2mg/L in the western area of the lake, but decreased with increasing of TN and IP concentrations when they were 5. 8 - 9. 4 and 0. 2 - 0. 3mg/L, respectively. It increased with increasing TP concentrations when it was above 0. 3mg/L. The change of Chl-a content maybe modulated with algal biological activity and nutrients in the water and the sediment. It demonstrated that decrease inputs of phosphorus and internal phosphorus in the western area of the lake could efficiently reduce the nutrient level and improve water quality in lake Chaohu.