Continuous measurement and modeling of CO2 losses from a peatland stream during stormflow events
Continuous measurement and modeling of CO2 losses from a peatland stream during stormflow events
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DOI：
10.1029/2008wr007284
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发表时间：
2008-12-13
影响因子：
5.4
通讯作者：
Billett, M. F.
中科院分区：
文献类型：
--
作者：
Dinsmore, K. J.;Billett, M. F.
虽然已知排干泥炭地和湿地系统的溪流在二氧化碳中相对于大气是过饱和的，但对响应极端水文事件的短期时间变异性知之甚少。在这里，我们使用水下非弥散红外(NDIR)传感器对苏格兰泥炭地溪流中18次风暴期间的二氧化碳浓度进行连续测量。个别风暴表现出3种不同类型的磁滞回线。我们认为，环路形式的差异可能是由于土壤水分相对贡献的差异或贡献集水源区域的差异所致。在整个研究期间，我们发现了负的浓度-排放关系，这表明在低流量条件下，富含CO2的深层泥炭/地下水是水生CO2的主要来源。通过剔除稀释的影响和估计二氧化碳的添加和损失，我们还表明了地表泥炭二氧化碳输入到溪流和暴雨期间逃逸损失的重要性。通过将数据集分为“暴风雨”和“枯水期”，得到了二氧化碳时间变异性的最佳模型。在研究期间，下游二氧化碳出口以暴雨事件为主(71%)，突出了准确计算高流量二氧化碳来源的重要性。
While streams draining peatland and wetland systems are known to be supersaturated in CO2 with respect to the atmosphere, relatively little is known about short-term temporal variability in response to extreme hydrological events. Here, we use submerged, nondispersive infrared (NDIR) sensors to make continuous measurements of CO2 concentrations during 18 storm events in a Scottish peatland stream. Individual storms exhibited 3 distinct types of hysteresis loop. We suggest that differences in loop form may be due to differences in the relative contributions of soil water or differences in the contributing catchment source area. We found a negative concentration-discharge relationship over the full study period, suggesting that CO2-rich deep peat/groundwater was the major source of aquatic CO2 under low flow conditions. By removing the effect of dilution and estimating additions and losses of CO2, we also show the importance of both surface peat CO2 inputs into the stream and evasion loss during stormflow. The best model of temporal variability in CO2 was achieved by separating the data set into "stormflow'' and "dry periods.'' Downstream CO2 export during the study period was dominated by stormflow events (71%), highlighting the importance of accurately accounting for high-flow CO2 sources.