摘要
岩石风化产生的碳汇是全球碳循环的重要组成部分,文中对清水江流域主要离子组成进行分析测定,通过主成分分析、化学物质平衡法和扣除法估算流域岩石风化速率及对大气CO_2的消耗量.结果表明,流域河水溶质主要来源于碳酸盐岩和硅酸盐岩风化,并以碳酸盐岩风化为主.碳酸盐、硅酸盐、大气CO_2对河水溶质的贡献率分别为58.28%、17.38%、17.74%.流域岩石化学风化速率为109.97 t·(km^2·a)^(-1),与乌江接近,高于全球流域均值.流域岩石风化对大气CO_2的消耗通量为7.25×10~5mol·(km^2·a)^(-1),岩石风化对大气CO_2的消耗量为12.45×10~9mol·a^(-1),其中,碳酸盐岩风化消耗量占63.13%,为7.86×10~9mol·a^(-1),硅酸盐岩风化消耗量占36.87%,为4.59×10~9mol·a^(-1).SO_4^(2-)、F^-、NO_3^-的相关分析及空间分布特征表明,人为活动对清水江流域河水溶质的影响不容忽视,其贡献率为4.87%.
Carbon sink produced during rock weathering is critical to global carbon cycles. In this work,the major ion chemistry and ion sources of Qingshuijiang River Basin were investigated. The principal component analysis,mass balance approach and deduction method were applied for estimating the weathering rate and atmospheric CO2 consumption via the chemical weathering of rocks. The results demonstrated that the chemical weathering of carbonate and silicate rocks within the drainage basin was the main source of the dissolved chemical substances in the Qingshuijiang River Basin,prior to carbonate rock weathering. Some 58. 28% of the total dissolved chemical substances were derived from the chemical weathering of carbonate rock,17. 38% from the dissolution of silicate rock,and 17. 74% from atmospheric CO2 contribution rates. The chemical weathering rate of this catchment was estimated to be109. 97 t·（ km^2·a）^-1,which was comparable to Wujiang River Basin,but higher than the average of global rivers. Furthermore,the atmospheric CO2 consumption rate was estimated to be 7. 25 × 10^5mol·（ km^2·a）^-1. The CO2 flux consumed by the rock chemical processes within this catchment was 12. 45 × 10^9mol·a^-1,of which about 63. 13%（ 7. 86 × 10^9mol·a^-1） was resulted from carbonate weathering and 36. 87%（ 4. 59 × 10^9mol·a^-1） from silicate weathering. The CO2 consumed by rock chemical weathering in the Qingshuijiang River reduced the atmospheric CO2 level and constituted a significant part of the global carbon budget. Correlation and spatial distribution analysis of SO4^（2-）,F-,NO3^-showed that anthropogenic activities contributed remarkably to dissolved solutes and associated CO2 consumption worldwide,and anthropogenic inputs probably contributed some 4. 87% to the dissolved solutes in the Qingshuijiang River.
出处
《环境科学》
EI
CAS
CSCD
北大核心
2016年第12期4671-4679,共9页
Environmental Science
基金
国家自然科学基金项目(42603123)
中国博士后科学基金项目(2014M562388)
水利部公益性行业科研专项(201401050)
关键词
碳汇
化学风化
贡献率
水化学
清水江
carbon sink
chemical weathering
contribution rate
water chemistry
Qingshuijiang River
作者简介
吕婕梅（1988～），女，博士研究生，主要研究方向环境地球化学，E-mail：lvjm0728@163．com
通讯联系人，E-mail：anyl@gzu．edu．cn
