粤北水边河流域钙元素迁移的基岩制约作用  

Restriction of bedrock to calcium ion migration in the Shuibian river basin of northern Guangdong Province

作　　者：涂旭 魏兴琥[1] 曾发明 TU Xu;WEI Xinghu;ZENG Faming(School of Food Science and Engineering,Foshan University,Foshan,Guangdong 528000,China;School of Environmental and Chemical Engineering,Foshan University,Foshan,Guangdong 528000,China;Foshan Ecological Carbon Sequestration Engineering Research Center,Foshan,Guangdong 528000,China)

机构地区：[1]食品科学与工程学院,佛山科学技术学院,广东佛山528000 [2]环境与化学工程学院,佛山科学技术学院,广东佛山528000 [3]佛山市生态固碳工程技术研究中心,广东佛山528000

出　　处：《中国岩溶》2024年第1期105-113,共9页Carsologica Sinica

基　　金：国家自然科学基金项目(42007177,41571091)。

摘　　要：岩石风化是控制流域水体水化学特征的关键因素之一。为探索岩溶流域中不同基岩风化作用对地表水化学的影响,本文选择粤北典型岩溶流域(水边河)为研究对象,以水体[Ca^(2+)]变化和钙迁移机制为研究主线,通过连续5年的系统调查及采样分析,揭示不同岩性风化对干流水体中Ca^(2+)输送通量的贡献率和岩溶流域钙元素迁移的影响机理。结果表明:(1)不同基岩支流的水体[Ca^(2+)]差异明显,特别是在干季,碳酸盐岩支流水体的[Ca^(2+)]分别是花岗岩、砂岩和砾岩支流的3.8倍、4.7倍、14.9倍;(2)不同基岩支流汇入干流后,水化学变化具有滞后性,并且呈现季节性差异。其中,碳酸盐岩支流汇入后,干流水体的[Ca^(2+)]会滞后升高,而其他支流会稀释[Ca^(2+)],产生稀释作用,其效果在湿季比干季更明显;(3)通过统计分析得出,碳酸盐岩支流在流域土地面积占比为28%,而其对流域水体中[Ca^(2+)]的贡献率达到83%,说明岩溶流域中碳酸盐岩的风化的制约着钙元素的迁移过程;(4)2016-2020年间,水边河向连江输送的钙通量平均值为7.2×10^(4) t·a^(-1),其中,湿季平均输送量为5.8×10^(4) t·a^(-1),干季平均为1.4×10^(4) t·a^(-1);但岩溶水体中钙元素迁移不仅仅有水体溶解的Ca^(2+),还有沉积态钙迁移和水生生物的钙迁移过程,而农业活动及酸雨等过程可导致水体中[Ca^(2+)]发生明显变化,因此,农业活动和酸雨等对钙迁移的影响需要多加关注。As a highly researched topic in hydrochemistry,rock weathering is a key factor in controlling the hydrochemical characteristics in a watershed.In karst watersheds,the weathering of carbonate rocks has a significant impact,leading to high levels of Ca^(2+)and Mg^(2+)cations,as well as HCO_(3)-watersheds,the dominant cations are Na^(+)or K^(+),with lower levels of Ca^(2+),and the main anions are Cl^(-),NO_(3)^(-),and others.Calcium is a vital element that plays a crucial role in the structure and functioning of karst ecosystems.Therefore,understanding the differences in Ca^(2+)concentrations and the interactions between external water and karst water is essential for accurately assessing the hydrochemical impact of bedrock on karst watersheds.The Shuibian river is a typical karst river located in the northern part of Guangdong Province,China.It spans a distance of 78 kilometers with an average gradient of 1.8‰.Its geographical coordinates are E112°42'13.511"-E113°15'3.730",and N24°21'28.22"-N23°55'34.61".The total area of its basin is approximately 857 square kilometers.The region where the river is situated falls under a subtropical monsoon climate,characterized by hot and humid summers.The prevailing warm and moist airflow comes from the south in summer.The average annual temperature ranges from17.5℃to 20.7℃,and the average annual precipitation is between 1,830-1,879 mm.The climate exhibits distinct wet and dry seasons.The wet season lasts from March to September,accounting for over 70% of the annual rainfall,while the dry season occurs from October to February,with less precipitation.The research area is predominantly composed of four different types of bedrock:sandstone,carbonate rock,granite,and conglomerate.To explore the impact of weathering processes of these various bedrock types on the chemical composition of surface water in karst regions,this study focuses on a representative karst watershed called the Shuibian river in northern Guangdong Province.The main objective of this study is to investi

关 键 词：岩溶流域 钙迁移通量 基岩类型 钙离子浓度 外源水 

分 类 号：P342[天文地球—水文科学]