Dissolved inorganic carbon and its isotopic differentiation in cascade reservoirs in the Wujiang drainage basin  

作　　者：YU YuanXiu LIU CongQiang WANG FuShun WANG BaoLi LI Jun LI SiLiang 

机构地区：[1]State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China [2]Institute of Applied Radiation, School of Environmental and Chemical Engineering, Shanghai University, Shanghai 201800, China [3]Graduate University of Chinese Academy of Sciences, Beijing100049, China

出　　处：《Chinese Science Bulletin》2008年第21期3371-3378,共8页

基　　金：the Ministry of Science and Technology of China (Grant No. 2006CB403205);the National Natural Science Foundation of China (Grant Nos. 90610037, 40571158 and 40721002)

摘　　要：Three cascade reservoirs,built in different periods of time in the Wujiang drainage basin,were inves-tigated in this study.Samples were taken at the surface and also at 20,40,60,80 m depths in front of the dams in April,July,October of 2006 and January of 2007.Chemical parameters were calculated and the concentrations of dissolved inorganic carbon DIC and its isotopic composition(δ13CDIC) were de-termined.In surface waters,the δ13CDIC values are high in summer and autumn and low in winter and spring,while the DIC concentrations are relatively low in summer and autumn and relatively high in winter and spring.In the water column,the DIC concentrations increase while δ13CDIC values decrease with water depth.DIC in various reservoirs is significantly different in isotopic composition from that in natural rivers,but is close to that in natural lakes.In addition,in surface waters,the δ13CDIC values tend to become lower whereas the nutrition level tends to become higher with increasing age of the reser-voirs.The conclusion is that after dam blocking,changes took place in the hydrochemical properties of river water,and the impounding rivers developed toward lakes and swamps.In addition,differentiation in DIC isotopic composition may be used to some extent to trace the evolution process of a reservoir.Three cascade reservoirs, built in different periods of time in the Wujiang drainage basin, were investigated in this study. Samples were taken at the surface and also at 20, 40, 60, 80 m depths in front of the dams in April, July, October of 2006 and January of 2007. Chemical parameters were calculated and the concentrations of dissolved inorganic carbon [DIC] and its isotopic composition （δ613CDIC） were determined. In surface waters, the δ613CDIC values are high in summer and autumn and low in winter and spring, while the DIC concentrations are relatively low in summer and autumn and relatively high in winter and spring. In the water column, the DIC concentrations increase while δ613CDIC values decrease with water depth. DIC in various reservoirs is significantly different in isotopic composition from that in natural rivers, but is close to that in natural lakes. In addition, in surface waters, the δ613CDIC values tend to become lower whereas the nutrition level tends to become higher with increasing age of the reservoirs. The conclusion is that after dam blocking, changes took place in the hydrochemical properties of river water, and the impounding rivers developed toward lakes and swamps. In addition, differentiation in DIC isotopic composition may be used to some extent to trace the evolution process of a reservoir.

关 键 词：无机物 碳同位素 进化方式 水库 

分 类 号：P64[天文地球—地质矿产勘探]