Interception, degradation and contributions of terrestrial organic carbon obtained from lignin analysis in Wujiang River, southwest China  

作　　者：Xin Lin Yujie Wang Jinhua Zhang Ming Yang Xueping Chen Fushun Wang Jing Ma 

机构地区：[1]School of Environmental and Chemical Engineering,Shanghai University,Shanghai 200444,China

出　　处：《Acta Geochimica》2021年第6期857-870,共14页地球化学学报（英文）

基　　金：funded by the National Key Research and Development Program of China(2016YFA0601003);additional supporting was provided by the National Natural Science Foundations of China(Nos.21477072 and 41573064).

摘　　要：Understanding the fate of terrestrial organic carbon(OC)in a cascade impoundment system is critical for recognizing the role of carbon sink for reservoirs.Surface sediments collected from eight cascade reservoirs across the Wujiang River,southwestern China,were analyzed for elemental and stable carbon isotopic(δ^13C)composition,and lignin phenols(∑8 andΛ8)to investigate the spatial distribution,contribution,origin and degradation of sedimentary terrestrial OC.The values of total organic carbon(TOC)and∑8 exhibited a remarkable reduction along the upstream-downstream transect suggesting the trapping effect of cascade-damming.A relatively broad range ofδ^13C(-26.61 to-25.54%,95%CI)and C/N(6.80-18.20)indicated mixed allochthonous/autochthonous OC sources in surface sediments.The quantitative simulation indicates that the OC of the sediments mainly was derived from terrestrial organic matter.Soilderived OC rather than C_(3)vascular plant-derived OC makes a major contribution to sedimentary terrestrial OC in reservoirs on karst terrain.As evidenced by lignin compositions andδ^13C,the predominant vascular plant origins of terrestrial OC along the Wujiang River are non-woody angiosperm C_(3)plants.The aged reservoirs showed a trend of increasing contribution of autochthonous OC,which potentially weaken the role of carbon sink for reservoirs.The relationship between runoff inputs,watershed area/water surface area ratios,and water residence time and Λ8 were explored,indicating the natural and anthropogenic influences on terrestrial OC remains very complex in a cascade-damming river.

关 键 词：Lignin phenols Terrestrial organic carbon Cascade impoundment 

分 类 号：P59[天文地球—地球化学]