东洞庭湖区芦苇群落生长对水质的影响

Effect of Phragmites Communis Growth on Water Quality in East Dongting Lake Area

为了解东洞庭湖区芦苇生长期对水质的影响,分期对芦苇分布的3个群落(A、B、C区)进行现场调查与水质采样测试.采用相关分析法分析芦苇生长区水体主要污染因子相互关联及污染成因,同时运用综合污染指数法、综合营养状态指数法评价芦苇不同生长期水体的污染状况、富营养化程度及其变化趋势.结果表明:芦苇生长区水质主要污染物为N、P,其中A区污染相对较重,腐解期对A区N、P含量影响较大;B、C区水质与主湖体水质差异较小.综合营养状态指数与综合污染指数表明,A区水体富营养化及综合污染最重.BOD_(5)/COD_(Mn)值表明,A区污染较重可能与芦苇腐解等外源污染较重及局部水体扩散能力较差有关.研究显示,东洞庭湖区芦苇腐解对局部水质存在不同程度的影响,尤其湿地核心区受A区来水影响较大.

In order to investigate the effect of phragmites communis growth stages on water quality in East Dongting Lake Area,the field investigation and water quality sampling test of three phragmites communis community(areas A,B and C)were carried out by stages.The correlation analysis method was used to analyze the correlation and pollution causes of main pollution factors in phragmites communis growing area.Meanwhile the pollution status,eutrophication degree and change trend of phragmites communis growth stages on water bodies were evaluated by comprehensive pollution index and trophic level index.The results show that the main pollutants of water quality in phragmites communis growing area are nitrogen and phosphorus,the pollution in area A is relatively heavy,and the decomposition period has a great impact on the content of nitrogen and phosphorus in area A.The water quality of areas A and B is close to that of the main lake.Trophic level index and comprehensive pollution index shows that the eutrophication and comprehensive pollution in area A are the most serious.Correlation analysis and BOD_(5)/COD_(Mn) ratio shows that the heavy pollution in area A may be related to the heavy external pollution such as phragmites communis decomposition and the poor diffusion capacity of local water bodies.The research shows that phragmites communis decomposition in East Dongting Lake Area has varying degrees of impact on local water quality,especially the wetland core area is greatly affected by the water from area A.