Sensitivity of chemical weathering and dissolved carbon dynamics to hydrological conditions in a typical karst river.
Sensitivity of chemical weathering and dissolved carbon dynamics to hydrological conditions in a typical karst river.
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DOI：
10.1038/srep42944
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发表时间：
2017-02-21
影响因子：
4.6
通讯作者：
Liu CQ
中科院分区：
文献类型：
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作者：
Zhong J;Li SL;Tao F;Yue F;Liu CQ
为了更好地理解水文条件控制大型河流化学风化和碳动力学的机制，我们研究了溶解无机碳（DIC）的水化学和碳同位素组成的基础上高频采样在中国西南部的乌江流域的碳酸盐地区。主要溶解溶质的浓度并不严格遵循稀释过程，随着流量的增加，和非地球化学过程导致浓度-流量关系的变化。溶解溶质的时间变化与风化特征和雨季水文条件密切相关。溶解碳的浓度和碳同位素组成随流量的变化而变化，表明水文条件和地球化学过程控制溶解碳的动态。生物CO2排放和土壤CO2强烈的碳酸盐风化作用是丰水期各种水文条件下碳变化的主要原因。通过混合模型计算得到的DICbio（DIC来源于生物）浓度随流量的增加而增加，表明DICbio入流是这条典型岩溶河流中DIC恒化行为的主要驱动力。这项研究强调了化学风化和碳动力学对河流系统水文条件的敏感性。
To better understand the mechanisms that hydrological conditions control chemical weathering and carbon dynamics in the large rivers, we investigated hydrochemistry and carbon isotopic compositions of dissolved inorganic carbon (DIC) based on high-frequency sampling in the Wujiang River draining the carbonate area in southwestern China. Concentrations of major dissolved solute do not strictly follow the dilution process with increasing discharge, and biogeochemical processes lead to variability in the concentration-discharge relationships. Temporal variations of dissolved solutes are closely related to weathering characteristics and hydrological conditions in the rainy seasons. The concentrations of dissolved carbon and the carbon isotopic compositions vary with discharge changes, suggesting that hydrological conditions and biogeochemical processes control dissolved carbon dynamics. Biological CO2 discharge and intense carbonate weathering by soil CO2 should be responsible for the carbon variability under various hydrological conditions during the high-flow season. The concentration of DICbio (DIC from biological sources) derived from a mixing model increases with increasing discharge, indicating that DICbio influx is the main driver of the chemostatic behaviors of riverine DIC in this typical karst river. The study highlights the sensitivity of chemical weathering and carbon dynamics to hydrological conditions in the riverine system.