Whole-Lake CO2 Dynamics in Response to Storm Events in Two Morphologically Different Lakes
Whole-Lake CO2 Dynamics in Response to Storm Events in Two Morphologically Different Lakes
复制标题
两个形态不同的湖泊对风暴事件的全湖二氧化碳动态响应
DOI：
10.1007/s10021-014-9799-8
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发表时间：
2014
期刊：
影响因子：
3.7
通讯作者：
P. Giorgio
中科院分区：
文献类型：
--
作者：
D. Vachon;P. Giorgio
在静默系统中，风暴事件后水文可能会发生巨大变化，可能会改变碳预算。特别是，在此类事件发生后，观察到地表水二氧化碳分压 (pCO2) 迅速增加。有几个过程可以解释湖泊二氧化碳动力学的这些变化，包括垂直混合、新陈代谢的增加和外部负荷的增加。为了评估这些不同过程的相对重要性，我们利用加拿大魁北克两个具有不同形态的湖泊的湖泊代谢和每日二氧化碳质量平衡预算的同时估计，重建了全湖每日二氧化碳预算。我们发现风暴事件导致全湖二氧化碳质量发生可变但显着的变化。此类事件通过引起湖泊新陈代谢的变化间接影响二氧化碳动态，并通过流入的雨水输入二氧化碳直接影响二氧化碳动态。风暴强度（就降水总量而言）影响这两个过程之间的平衡，但最终结果取决于湖泊形态测量。我们的结果表明，当风暴强度足以推动湖水更新率超过 1% day−1 时，外部二氧化碳负荷成为主导过程，压倒内部二氧化碳生产。然而，水文周转较慢的湖泊更容易受到内部调节的影响，并且可能在风暴事件后简单地将二氧化碳从下层水层重新分配到上层水层。因此，我们的结果表明，气候事件对流域-湖泊-大气联系的加强受到湖泊形态测量的强烈调节。在预测未来气候变化对区域碳预算和排放的影响时应考虑这些特征。
In lentic systems, hydrology can be dramatically altered after storm events, potentially modifying the carbon budget. In particular, rapid increases in the surface water carbon dioxide partial pressure (pCO2) have been observed following such events. Several processes may explain these shifts in lake CO2 dynamics, including vertical mixing, increases in metabolism, and increases in external loading. To evaluate the relative importance of these various processes, we reconstructed the whole-lake daily CO2 budget using concurrent estimates of lake metabolism and daily CO2 mass balance budgets in two lakes with distinct morphometries located in Québec, Canada. We found that storm events caused variable, but significant, changes in whole-lake CO2 mass. Such events influenced CO2 dynamics indirectly by inducing shifts in lake metabolism, and directly by importing CO2 by the inflowing storm waters. Storm intensity (in terms of total amount of precipitation) influences the balance between these two processes, but the final outcome depends on lake morphometry. Our results suggest that when storms are intense enough to drive lake water renewal rate beyond 1% day−1, external CO2 loadings became the dominant process, overwhelming internal CO2 production. Lakes with slower hydrological turnover, however, are more susceptible to internal regulation and may simply re-allocate CO2 from the hypolimnion to the epilimnion following a storm event. Our results thus suggest that this tightening of the watershed-lake-atmosphere linkage by climatic events is strongly modulated by lake morphometry. These features should be considered when predicting the impact of future climate change on regional C budgets and emissions.