HYDROLOGICAL CONTROLS ON DISSOLVED ORGANIC-CARBON DURING SNOWMELT IN THE SNAKE RIVER NEAR MONTEZUMA, COLORADO
HYDROLOGICAL CONTROLS ON DISSOLVED ORGANIC-CARBON DURING SNOWMELT IN THE SNAKE RIVER NEAR MONTEZUMA, COLORADO
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DOI：
10.1007/bf00024390
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发表时间：
1994-01-01
期刊：
影响因子：
4
通讯作者：
MCKNIGHT, DM
中科院分区：
文献类型：
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作者：
HORNBERGER, GM;BENCALA, KE;MCKNIGHT, DM
定量了解控制水源中溶解有机碳(DOC)变化的因素具有科学意义，至少有两个原因。首先，为了从根本上理解这些系统，需要量化Lottic系统的总体碳预算。其次，DOC与其他溶解物质(特别是重金属)相互作用很强，在污染物的传输中起着重要作用。在科罗拉多州蒙特祖马附近的Snake River，1980年至1986年的DOC测量显示，DOC浓度从融雪期很早的峰值迅速下降。DOC峰值浓度出现在溪流峰值流量前一个月左右。DOC随时间的下降近似成指数下降，这表明简单的冲洗机制可以解释这种响应。我们研究了解释蛇河DOC变化的水文机制，方法是使用TOPMODEL模拟集水区的水文响应，并通过一个简单的模型来选择预测的流量，该模型可以解释DOC的时间变化。从概念上讲，DOC模型代表了一个陆地(土壤)水库，DOC在枯水期积聚，然后被渗入的融水冲走。该模型再现了观测到的蛇河DOC变化的主要特征，从而为定量联系水文过程与旱地流域碳循环奠定了基础。模型结果表明，在洪峰流量期间，蛇河流域的土壤中有很大一部分对河流中的DOC有贡献。我们的工作是首次尝试定量描述源流中DOC动态的水文控制。通过对通过不同DOC源区的水通量和可在这些区域累积的DOC的量施加质量平衡约束，通过该模型来研究这些控制。
A quantitative understanding of the factors controlling the variation of dissolved organic carbon (DOC) in headwater streams is of scientific concern for at least two reasons. First, quantifying the overall carbon budgets of lotic systems is needed for a fundamental understanding of these systems. Second, DOC interacts strongly with other dissolved substances (heavy metals in particular) and plays an important role in the transport of contaminants.In the Snake River near Montezuma, Colorado, measurements of DOC from 1980 to 1986 show rapid decreases in concentration from a peak very early in the snowmelt period. Peak DOC concentrations occur approximately one month prior to peak discharge in the stream. The decline in DOC with time is approximately exponential, suggesting that a simple flushing mechanism can explain the response. We examined hydrological mechanisms to explain the observed variability of DOC in the Snake River by simulating the hydrological response of the catchment using TOPMODEL and routing the predicted flows through a simple model that accounted for temporal changes in DOC. Conceptually the DOC model represents a terrestrial (soil) reservoir in which DOC builds up during low flow periods and is flushed out by infiltrating meltwaters. The model reproduces the main features of the observed variation in DOC in the Snake River and thus lays the foundation for quantitatively linking hydrological processes with carbon cycling through upland catchments. Model results imply that a significant fraction of the soils in the Snake River catchment contribute DOC to the stream during peak discharge. Our work represents one of the first attempts to quantitatively describe the hydrological controls on DOC dynamics in a headwater stream. These controls are studied through the model by imposing mass balance constraints on both the flux of water through the various DOC source areas and the amount of DOC that can accumulate in these areas.