Variable flushing mechanisms and landscape structure control stream DOC export during snowmelt in a set of nested catchments
Variable flushing mechanisms and landscape structure control stream DOC export during snowmelt in a set of nested catchments
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可变冲刷机制和景观结构控制一组嵌套集水区融雪期间 DOC 输出流
DOI：
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发表时间：
2010
期刊：
影响因子：
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通讯作者：
B. McGlynn
中科院分区：
文献类型：
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作者：
V. Pacific;K. Jencso;B. McGlynn
融雪过程中河流溶解有机碳的动态变化一直是研究的重点，并提出了许多来自河岸和高地地区的溶解有机碳的动员和输送机制。然而，景观结构控制DOC输出河岸和高地景观要素仍然知之甚少。我们调查了流和地下水DOC动态三个样带和7个相邻的，但不同的集水区与一系列的景观特征在融雪（4月15日至7月15日）在北方落基山脉，蒙大拿州。我们观察到一系列的DOC出口动态河岸和高地景观设置和不同程度的水文之间的连接流，河岸，高地区。DOC从河岸带输出需要一个水文连接在河岸流界面，并发生在景观位置与各种上坡累积面积（UAA）和湿度状态。与此相反，动员DOC从高地出现局限于整个高地河岸流连续的水文连接的地区，这通常只发生在高UAA的地区，和/或在高湿度的时候。此外，DOC丰富的河岸和湿地区的相对程度强烈影响流域DOC输出。河流DOC累积输出量最高的是河岸到高地面积比例较大的集水区，在整个研究期间范围为6.3至12.4 kg ha−1。这项研究表明，水文连通性和DOC源区的时空交叉驱动流DOC输出。
Stream DOC dynamics during snowmelt have been the focus of much research, and numerous DOC mobilization and delivery mechanisms from riparian and upland areas have been proposed. However, landscape structure controls on DOC export from riparian and upland landscape elements remains poorly understood. We investigated stream and groundwater DOC dynamics across three transects and seven adjacent but diverse catchments with a range of landscape characteristics during snowmelt (April 15–July 15) in the northern Rocky Mountains, Montana. We observed a range of DOC export dynamics across riparian and upland landscape settings and varying degrees of hydrologic connectivity between the stream, riparian, and upland zones. DOC export from riparian zones required a hydrologic connection across the riparian–stream interface, and occurred at landscape positions with a wide range of upslope accumulated area (UAA) and wetness status. In contrast, mobilization of DOC from the uplands appeared restricted to areas with a hydrologic connection across the entire upland–riparian–stream continuum, which generally occurred only at areas with high UAA, and/or at times of high wetness. Further, the relative extent of DOC-rich riparian and wetland zones strongly influenced catchment DOC export. Cumulative stream DOC export was highest from catchments with a large proportion of riparian to upland area, and ranged from 6.3 to 12.4 kg ha−1 across the study period. This research suggests that the spatial/temporal intersection of hydrologic connectivity and DOC source areas drives stream DOC export.