| 典型喀斯特河流水-气界面二氧化碳交换特性及其营养调控因素 |
| 摘要点击 2208 全文点击 604 投稿时间：2020-06-16 修订日期：2020-08-02 |
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| 中文关键词 喀斯特河流 二氧化碳排放 营养元素 耦合关系 碳循环 |
| 英文关键词 karst rivers carbon dioxide emissions nutrients environmental coupling carbon cycle |
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| 中文摘要 |
| 为探索喀斯特河流水-气界面二氧化碳（CO2）交换特性及其营养控制因素，以我国典型喀斯特河流——芙蓉江为研究对象，探索了区域气象水文参数、碳酸盐平衡参数、营养元素及总有机碳（TOC）的空间变化特征，同时分析了CO2分压（pCO2）的空间变化调控因素，pCO2与总氮（TN）、总磷（TP）和TOC及其化学计量比的耦合关系，对比了该研究河流与世界河流的CO2排放情况.结果表明，芙蓉江水-气界面CO2交换速率（k）在2.71~13.0 m·d-1范围内，pCO2在78.5~21491.2 Pa范围内，且支流高于干流；河流表层水体TOC、TN和TP分别为（302.8±50.1）、（128.9±67.9）和（0.65±0.98）μmol·L-1，整体表现为磷限制营养状态；河流pCO2与磷及其相关的化学计量比显著耦合，说明微生物新陈代谢是河流CO2饱和的主要原因；芙蓉江水-气界面CO2排放通量（F）为（534.5±801.4） mmol·（m2·d）-1，高于一些世界河流，具有巨大的CO2排放潜力. |
| 英文摘要 |
| To explore water-air carbon dioxide (CO2) exchange and its nutritional controls in karst rivers, water sampling and analyses were conducted in the Furong River as a representative karst river system. Regional hydrometeorological characteristics, carbonate system parameters, total organic carbon (TOC), nutrients and their stoichiometric ratios, and the riverine pressure of aqueous CO2 (pCO2) and its couplings to trophic status were analyzed. The results showed that gas transfer velocity of CO2 (k) varied between 2.71 and 13.0 m·d-1. Riverine pCO2 varied from 78.5 Pa to 21491.2 Pa and was significantly higher in the tributaries than the main stem. Riverine TOC, total nitrogen (TN), and total phosphorus (TP) concentrations were (302.8±50.1), (128.9±67.9), and (0.65±0.98) μmol·L-1, respectively, demonstrating the trophic status of P-limitation. Riverine pCO2 was tightly linked to P-related parameters, suggesting that in-situ metabolism triggered aquatic CO2 supersaturation. Water-air CO2 flux (F) averaged (534.5±801.4) mmol·(m2·d)-1 in the Furong River, which is higher than most of the world's rivers, and thus indicates high potential CO2 emissions. |
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