摘要
长江流域面积巨大,岩性多变,加之三峡大坝等重大水利工程的影响,干流河水的水化学成因存在较大争议。此外,以往研究中流域矿物风化过程的碳汇通量估算一般基于阳离子来源分析,但该算法通常涉及多种矿物端元的参数选取,结果具有不确定性。本次研究对长江干流水化学的时空演变进行了整体分析,并基于上游河水样品含量的校正与计算,提出了一种计算矿物风化过程碳汇通量的新方法。研究结果表明,蒸发盐溶解、循环盐作用、矿物风化及硫酸盐溶解是控制长江干流河水离子组成的主要水文地球化学作用,而人类活动主要影响了离海距离3000 km以内河水含量;长江上游干流硅酸盐风化消耗CO_(2)速率为1.16×10^(5) mol/(km^(2)·a),碳酸盐风化消耗CO_(2)速率为4.75×10^(5)mol/(km^(2)·a)。本研究有助于加深对长江干流主要水文地球化学作用的认识,丰富和完善碳循环研究理论。
Because river water in the Yangtze River watershed with a huge area is influenced by variable lithologies and large-scale water projects such as the Three Gorges Dam,the hydrochemical origins of the main stream are still controversial.Furthermore,previous estimations on the carbon sink in the watershed caused by mineral weathering are mostly based on the mass-balance calculations of cations,but this method generally involves the selection of parameters of various mineral end-members,which causes the uncertainty of results.In this study,the temporal and spatial evolutions of hydrochemistry of the main stream are determined,and a new method for the determination of CO_(2) consumption rates during mineral weathering processes are proposed based on the mass-balance calculations of HCO_(3)^(-) of the upper reaches.The results show that dissolution of evaporites,circulating salts,minerals weathering and sulfate dissolution are the main hydrogeochemical reactions controlling the ionic compositions of river water of the mainstream of the Yangtze River,while human activities mainly control the contents of in the river water within 3000 km from the estuary.The CO_(2)consumption rates of silicate weathering and carbonate weathering in the upper reaches of the Yangtze River are 1.16×10^(5)mol/(km^(2)·a)and 4.75×10^(5)mol/(km^(2)·a),respectively.This study may provide a better understanding of the major hydrochemical processes,enriches and promotes the theory of carbon cycle.
作者
张鸿
周权平
姜月华
金阳
杨国强
顾轩
梅世嘉
王晓龙
ZHANG Hong;ZHOU Quanping;JIANG Yuehua;JIN Yang;YANG Guoqiang;GU Xuan;MEI Shijia;WANG Xiaolong(Nanjing Center,China Geological Survey,Nanjing,Jiangsu 210016,China;Key Laboratory of Watershed Eco-Geological Processes,Ministry of Natural Resources,Nanjing,Jiangsu 210016,China;Graduate School of Chinese Academy of Geological Sciences,Beijing 100037,China;State Key Laboratory of Lake Science and Environment,Nanjing Institute of Geography and Limnology,Chinese Academy of Science,Nanjing,Jiangsu 210008,China)
出处
《水文地质工程地质》
CAS
CSCD
北大核心
2022年第1期30-40,共11页
Hydrogeology & Engineering Geology
基金
中国地质调查局地质调查项目(DD20190260)。
关键词
长江干流
三峡大坝
多元统计分析
水化学成因
大气CO_(2)消耗
mainstream of the Yangtze River
Three Gorges Dam(TGD)
multivariate statistical analysis
hydrochemical origin
CO2 consumption
