太湖大浦湖区环境变化的沉积物同位素响应特征  

LAKE ENVIRONMENTAL CHARACTERISTICS RECOREDED BY ISOTOPES IN SEDIMENTS OF DAPU AREA IN LAKE TAIHU

作　　者：徐龙生[1,2] 吴敬禄[1] 

机构地区：[1]中国科学院南京地理与湖泊研究所湖泊与环境国家重点实验室,南京210008 [2]中国科学院大学,北京100049

出　　处：《海洋地质与第四纪地质》2013年第2期137-142,共6页Marine Geology & Quaternary Geology

基　　金：国家基础研究发展规划项目(2008CB418005);国家自然科学基金项目(41073010;40673015)

摘　　要：在137 CS年代学分析的基础上,通过对太湖大浦湖区钻孔沉积物的有机质碳、氮同位素(δ13 C、δ15 N)、总有机碳(TOC)、总氮(TN)、总磷(TP)等指标分析,开展了大浦湖区水体富营养化过程的同位素示踪研究。结果表明,随着湖泊水体从低营养向富营养演化,沉积物有机质δ13 C、δ15 N有明显的规律性变化。20世纪50年代以前,湖泊初级生产力低,水环境好,受人类活动影响弱,湖泊沉积记录表现为δ13 C偏高、δ15 N偏低以及较低含量的TOC、TN、TP;到1990s,湖泊环境出现显著的变化,湖泊初级生产力大幅提高,湖泊水环境恶化,营养化水平迅速提高,以致到达富营养阶段。相应地,湖泊沉积物有机质δ13 C快速下降而δ15 N升高,两者呈明显的反相关系(R=-0.81),而草型湖区东太湖δ13 C和δ15 N组合变化则呈明显正相关(R=0.96),反映了不同湖区同位素对环境变化的响应差异。据此,初步建立了藻型和草型湖泊富营养化过程的稳定碳氮同位素示踪模式。Through the determinations of δ13C,δ15N,total organic C,total N,total P in sediments of Dapu area in the Taihu Lake,this paper analyzed the eutrophication process of this area.The results showed that δ13C,δ15N in sediments had a significant change in patferns with the water evolution from low nutrition to eutrophication.Before 1950s,primary productivity of the lake was low and the water environment was good.Moreover,the impact of human activities was weak,and the lake sediments record showed a high value of δ13C and low values of δ15N,TOC,TN,TP.In 1990s,the lake environment changed significantly and the primary productivity increased substantially.As the result,the water environment deteriorated and the nutrition level increased rapidly resulting in eutrophication.Accordingly,the value of δ13C decreased rapidly,but δ15N increased,and the correlation showed significant reverse（R=-0.81）.However,the correlation between δ13C and δ15N was significantly positive（R=0.96）.This phenomenon reflected that the isotopic elements of different lakes responded differently to environmental changes,and the eutrophication patterns of grass-type lake and algae-type lake were initially established.

关 键 词：沉积物 稳定同位素 富营养化 太湖 

分 类 号：P951[天文地球—自然地理学]