亚热带季风区边缘坡立谷河流水化学特征及外源水的增汇效应:以广西马山县清波河流域为例  

Hydrochemical characteristics and karst carbon sink effect of border polje river in subtropical monsoon region:A case study of the Qingbo River in Mashan County,Guangxi

作　　者：张春来[1,2,3] 杨慧 黄芬[1,2,4] 邱成[5] 朱同彬 ZHANG Chunlai;YANG Hui;HUANG Fen;QIU Cheng;ZHU Tongbin(MNR and Guangxi Key Laboratory of Karst Dynamics,Institute of Karst Geology,Chinese Academy of Geological Sciences,Guilin 541004,China;International Research Centre on Karst Under the Auspices of UNESCO/National Center for International Research on Karst Dynamic System and Global Change,Guilin 541004,China;School of Environmental Studies,China University of Geosciences(Wuhan),Wuhan 430074,China;Pingguo,Guangxi Karst Ecosystem,National Observation and Research Station,Pingguo 531406,China;Guangxi Zhuang Autonomous Region Institute of Measurement and Testing,Nanning 530200,China)

机构地区：[1]中国地质科学院岩溶地质研究所自然资源部、广西岩溶动力学重点实验室,广西桂林541004 [2]联合国教科文组织国际岩溶研究中心/岩溶动力系统与全球变化国际联合研究中心,广西桂林541004 [3]中国地质大学(武汉)环境学院,湖北武汉430074 [4]广西平果喀斯特生态系统国家野外科学观测研究站,广西平果531406 [5]广西壮族自治区计量检测研究院,广西南宁530200

出　　处：《地学前缘》2024年第5期377-386,共10页Earth Science Frontiers

基　　金：国家自然科学基金广西联合基金项目(U22A20619);国家重点研发计划项目(2023YFD1902801);广西重点研发计划项目(桂科AB22035004);广西自然科学基金项目(2023GXNSFAA026465);中国地质调查局地质调查项目(DD20230547);自然资源部自然资源科技战略研究项目(2023-ZL-23)。

摘　　要：雨热同期的亚热带季风气候促进了岩溶碳汇的发生,受外源水补给的边缘坡立谷是岩溶区碳酸盐岩溶蚀作用强烈的区域,对该区不同类型水的水化学特征研究有助于加深对岩溶固碳作用规律的认识。本文运用数理统计、Piper三线图、Gibbs图和主要离子比值等多种方法,对亚热带典型边缘坡立谷的河流水化学特征、成因及其碳汇效应等进行了分析。结果显示:(1)边缘坡立谷的河水类型主要有外源水、外源水补给的地表河、外源水补给岩溶地下河和岩溶地下水等,其总离子浓度呈递增趋势,岩溶地下水的Ca 2+浓度平均值为91.06 mg/L,分别是外源水补给地下河水、外源水补给地表水和外源水的2.3、4.3和12.4倍,其中外源水补给的地表河水化学离子浓度变化较大;(2)外源水进入岩溶区后,Ca 2+和HCO-3浓度逐渐升高,方解石饱和指数逐渐偏正。在亚热带季风区大量降雨导致的水循环加快的情况下,外源水对碳酸盐岩具有较强的侵蚀性;但外源水无论以补给岩溶地下河还是以地表水进入岩溶区后,其与碳酸盐岩的反应时间或接触面积不足,影响了岩溶碳汇增汇的提升。The concurrent occurrence of rainfall and heat in the subtropical monsoon climate promotes the formation of karst carbon sinks.Border poljes,recharged by allogenic water,are regions with strong carbonate rock dissolution in karst areas.Studying the hydrochemical characteristics of different water types in these regions helps deepen the understanding of karst carbon sequestration processes.This paper employs statistical methods,Piper diagrams,Gibbs diagrams,and major ion ratios to analyze the hydrochemical characteristics,origins,and carbon sink effects of rivers in a typical subtropical border polje.The results show that:(1)The main types of river water in the border polje are allogenic water,surface rivers recharged by allogenic water,karst underground rivers recharged by allogenic water,and karst groundwater.The total ion concentration shows an increasing trend.The average concentration of Ca 2+in karst groundwater is 91.06 mg/L,which is 2.3,4.3,and 12.4 times that of underground rivers recharged by allogenic water,surface water recharged by allogenic water,and allogenic water,respectively.(2)After the allogenic water enters the karst area,the concentrations of Ca 2+and HCO-3 gradually increase,and the calcite saturation index shifts positively.In the context of an accelerated water cycle due to heavy rainfall in the subtropical monsoon region,the reaction time of allogenic water with carbonate rocks is insufficient after entering the karst area to strengthen erosion.Whether it is direct infiltration of allogenic water,or karst underground rivers or surface water recharged by allogenic water,it has significant potential for increasing the carbon sink.

关 键 词：边缘坡立谷 水化学 岩溶碳汇 外源水 增汇 

分 类 号：P592[天文地球—地球化学] P595[天文地球—地质学]