Dynamics of CO2 in a karst catchment in the southwestern plateau, China
Dynamics of CO2 in a karst catchment in the southwestern plateau, China
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西南高原喀斯特流域CO2动态
DOI：
10.1007/s12665-014-3591-0
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发表时间：
2015-03
期刊：
影响因子：
--
通讯作者：
Shilu Wang*, Kevin M. Yeager, Guojiang Wan, et al
中科院分区：
文献类型：
--
作者：
Shilu Wang*, Kevin M. Yeager, Guojiang Wan, et al
人们日益认识到，包括河流和湖泊在内的内陆沃茨在陆地输出的有机碳的运输、矿化和埋藏方面发挥着重要作用。然而，在许多地区，溶解无机碳（DIC）占主导地位的碳输出集水区。由于有机碳和无机碳的生产过程和周转时间不同，河流和湖泊排放的CO2可能对全球碳循环产生不同的影响，这取决于其来源。本文测定了中国西南高原碳酸盐岩流域泉水、河水和湖水的pCO 2和溶解氧浓度，并比较了过量CO2与O2消耗的比值（ΔCO2/ΔO2）。结果表明，与土壤CO2排放相比，地下水CO2逃逸（2.0 g C m− 2 year −1）在陆地碳损失方面微不足道。在河流中，由于过饱和的方解石沉淀是在某些季节产生CO2的重要机制。在湖泊中，HCO 3-在有利于光合作用的季节中为有机物生产和方解石沉积贡献了约75%的总碳供应。ΔCO2/ΔO2高的季节是湖泊CO2排放的主要时期，多余的CO2可能是由HCO 3 −滴定H+产生的。因此，湖泊CO2逃逸主要由pH值控制，而不是呼吸作用。泉水、河水和沃茨主要处理从集水区输出的DIC，其中HCO 3 −主要来自土壤CO2的碳酸盐风化，具有非常高的ΔCO2/ΔO2，可能来自有机质分解、根呼吸（自养）和酸溶解。因此，淡水CO2排放是集水区土壤CO2向大气的返回途径，而不是净初级生产力和净生态系统生产力。
Inland waters, including rivers and lakes, are increasingly recognized as playing significant roles in the transport, mineralization and burial of organic carbon exported from land. However, in many areas, dissolved inorganic carbon (DIC) dominates the carbon export from catchments. Owing to different production processes and turnover times of organic versus inorganic carbon, CO2 emitted from rivers and lakes may have different impacts on global carbon cycling depending on its origin. Here, pCO2 and dissolved oxygen concentrations were determined, and the ratios of excess CO2 to O2 depletion (ΔCO2/ΔO2) were compared in spring water, river water and lake water in a carbonate catchment located in the southwestern plateau region of China. Results show that groundwater CO2 evasion, at 2.0 g C m−2year−1, is insignificant in terms of terrestrial carbon loss compared with soil CO2 emission. In the rivers, calcite precipitation due to oversaturation is an important mechanism for CO2 production in some seasons. In the lake, HCO3− contributed approximately 75 % of the total carbon supply to organic matter production and calcite deposition during seasons favoring photosynthesis. The seasons which had high ΔCO2/ΔO2 are the main periods of CO2 emission from the lake, and the extra CO2 may be produced from HCO3− titration by H+. Thus, lake CO2 evasion was controlled primarily by pH, not respiration. The spring, river, and lake waters mainly process DIC exported from the catchment, of which HCO3− is primarily derived from carbonate weathering by soil CO2 that, with extraordinarily high ΔCO2/ΔO2, may originate from sources including organic matter decomposition, root respiration (autotrophic), and acid dissolution. Therefore, freshwater CO2 emission is a return pathway of catchment soil CO2 to the atmosphere more than that of net primary production and net ecosystem production.
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影响因子：
3.6
作者：
E. S. Lee;M. Hendry;P. Hollings
通讯作者：
E. S. Lee;M. Hendry;P. Hollings
影响因子：
--
作者：
E. Davidson;R. O. Figueiredo;D. Markewitz;A. Aufdenkampe
通讯作者：
E. Davidson;R. O. Figueiredo;D. Markewitz;A. Aufdenkampe
影响因子：
4
作者：
K. Sand‐Jensen;P. Staehr
通讯作者：
K. Sand‐Jensen;P. Staehr
影响因子：
3.4
作者：
K. C. Rice;J. Herman
通讯作者：
K. C. Rice;J. Herman
华南西江流域河流水地球化学：化学风化和二氧化碳消耗
影响因子：
3.4
作者：
Liu Cong-Qiang;Xu Zhifang
通讯作者：
Xu Zhifang