外源酸作用下流域岩石风化与碳汇效应--以漾弓江为例  

Rock weathering and carbon sink effects under exogenous acid action:A case study of the Yanggong river

作　　者：李雪艳 李灿锋 杨克好 陈瑞 熊银洪 王兴荣 王传宇 LI Xueyan;LI Canfeng;YANG Kehao;CHEN Rui;XIONG Yinhong;WANG Xingrong;WANG Chuanyu(Kunming General Survey Center for Natural Resources,China Geological Survey/Technology Innovation Center for Natural Ecosystem Carbon Sink,Ministry of Natural Resources,Kunming,Yunnan 650100,China)

机构地区：[1]中国地质调查局昆明自然资源综合调查中心/自然资源部自然生态系统碳汇工程技术创新中心,云南昆明650100

出　　处：《中国岩溶》2024年第4期742-752,共11页Carsologica Sinica

基　　金：中国地质调查局地质调查项目(ZD20220135)。

摘　　要：流域岩石风化是重要的碳源/汇过程,也是全球碳循环中的重要环节。外源酸参与流域岩石风化,影响碳元素的地球化学循环和流域碳源/汇效应。漾弓江属长江上游金沙江水系,流域岩石风化过程和碳汇效应尚不清楚。在2023年旱季和雨季分别采集了漾弓江的干流和主要支流的水样品(地表水点9个、地下水点6个),对主要离子浓度进行检测,并利用水化学平衡法和Galy估算模型分析该流域的岩风化类型,估算了碳酸与硫酸共同作用下的岩石风化CO_(2)消耗量。结果表明:(1)漾弓江流域水系离子成分主要源于硅酸盐岩和碳酸盐岩风化,水化学类型为HCO_(3)-Ca型或HCO_(3)-Ca·Mg型。(2)硫酸和碳酸共同参与了漾弓江流域的岩石风化过程。在不考虑硫酸作用时,漾弓江流域岩石风化的大气CO_(2)消耗量为38.35 t CO_(2)·km^(−2)·a^(−1),而当考虑了硫酸参与时,岩石风化碳汇量降至25.54 t CO_(2)·km^(−2)·a^(−1),扣除约33%,大大提高了计算精度。(3)漾弓江流域岩石风化的大气CO_(2)消耗量为4.27×10^(4) t CO_(2)·a^(−1),是一个碳汇过程。硫酸参与流域岩石的风化改变了区域碳循环,这是全球碳循环模型不可忽略重要环节。Rock weathering in the river basin is not only an essential carbon source and sink mechanism,but also an important link in the global carbon cycle.Rivers are indispensable components of water bodies,and the hydrochemistry of rivers is a representation of the degree to which weathering and denudation occur at the surface of the river basin.Therefore,it is possible for us to collect information on rock weathering in the river basin by conducting an analysis of the chemical compositions of rivers.In turn,the analytical results can be used for the estimation of weathering rates and the amount of carbon dioxide that is consumed by the Earth's atmosphere.The presence of exogenous acids in the process of rock weathering in the river basin has an impact on the geochemical cycling of carbon as well as the carbon source/sink effect.The chemical weathering rate of carbonatite is accelerated by sulfuric acid,but the weathering does not consume atmospheric carbon dioxide.As a result,the effect of sulfuric acid on carbonatite weathering should be taken into consideration when the amount of atmospheric carbon dioxide that is consumed by rock weathering in the basin is calculated.The Yanggong river is a part of the Jinsha river system located in the upper reaches of the Yangtze river.The process of rock weathering and the influence of carbon sinks in the Yanggong river basin are not yet fully understood.As a result of climate warming,the considerable increase in water output from the high-altitude area of this basin has accelerated the water cycle there.This will undoubtedly exert a strong influence on rock weathering rates and geochemical cycling processes that occur within the Yanggong river basin.In addition,a large number of coal layers are distributed in this basin,so the sulfuric acid produced by sulfide oxidation or the dissolution of carbonate rocks by sulfuric acid caused by human activities would also alter rock weathering rates in this basin.For this reason,it is necessary for us to do more research in order to quanti

关 键 词：岩石风化 碳汇效应 硫酸 碳酸盐岩 

分 类 号：X141[环境科学与工程—环境科学]