| 漓江流域丰水期外源酸对岩溶化学风化碳汇的影响 |
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| 引用本文：杜文越,王琪,蒲俊兵,于奭.2022.漓江流域丰水期外源酸对岩溶化学风化碳汇的影响[J].地球学报,43(4):449-460. |
| DOI：10.3975/cagsb.2022.041101 |
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| 基金项目:国家自然科学基金项目(编号: 42177075);广西重点研发专项(编号: 2021AB28002);中国地质调查局地质调查项目(编号: DD20190452) |
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| 中文摘要:于2020年4月对漓江流域主要干/支流进行采样及监测, 结合Gibbs图、离子比值、Galy模型和同位素特征值方法, 分析流域内水化学特征及外源酸对流域岩溶碳汇的影响。结果显示: (1)受碳酸盐岩风化影响所控制, 漓江水体主要水化学类型为HCO3-Ca; [Ca2++Mg2+]/[HCO– 3]的当量比均值为0.87, [Ca2++Mg2+]/ [HCO– 3+SO2– 4+NO– 3]的当量比均值为1.07, 指示碳酸盐岩风化过程受到外源输入的硫酸和硝酸影响; (2)漓江流域最终出口(阳朔断面)的碳汇通量为974.86×103 mol·(km2·a)–1。各支流碳汇量占总出口比例的波动较大, 比例最小为小溶江, 只占总通量1.44%, 而贡献比例最大则为良丰河35.74%, 甘棠江和良丰河贡献比例合计达57.04%。(3)流域内各支流CO2消耗量的占比均值为10.02%, 存在显著的空间变化, 受不同流域的地质分布和流量的影响明显。(4)外源酸风化碳酸盐岩的DIC贡献率介于13%~55%之间, 空间变化上, 大榕江和桃花江的贡献比例较大, 均高于50%, 而外源酸对阳朔断面DIC贡献率低至13%。 |
| 中文关键词:岩溶碳汇 水化学 岩石化学风化 外源酸 |
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| Effect of Exogenous Acids on the Karst Chemical Weathering and Carbon Sink in Lijiang River during the Wet Season |
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| Abstract:To analyze and evaluate the chemical characteristics of water and the influence of allogenic acids on the karst carbon sink of Lijiang River, the main stream sections and tributaries at the catchment were sampled and monitored by combining the Gibbs diagram, ion ratio, Galy model, and isotope characteristic values in April 2020. The results showed that (1) controlled by weathering of carbonate, the hydrochemistry of Lijiang River included HCO3-Ca, and the average equivalence ratio of [Ca2++Mg2+]/[HCO– 3] and [Ca2++Mg2+]/[HCO– 3+SO2– 4+NO– 3] were 0.87, 1.07, respectively. This indicates that the weathering process of carbonate is influenced by the allogenic sulfuric and nitric acid. (2) The carbon sink flux at the final outlet (Yangshuo section) of Lijiang River is 974.86×103 mol·(km2·a)–1. The proportion of carbon fluxes in the total exports fluctuated greatly between different tributaries, with Xiaorong River and Liangfeng River accounting for 1.44% and 35.74%, respectively. The Gantang River and Liangfeng River accounted for 57.04%. (3) The average proportion of CO2 consumption in the tributaries within the basin is 10.02% with significant differences in spatial variation, and is obviously influenced by geological distribution and flow rate of different basins. (4) The DIC contribution rate of chemical weathering process between carbonate and allogenic acid ranged from 13% to 55%. In terms of spatial variation, the DIC contribution rate of Darong River and Taohua River was higher than 50%, whereas the DIC contribution rate of allogenic acid is lower than 13% in the Yangshuo section. |
| keywords:karst carbon sink water chemistry rock chemical weathering allogenic acids |
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