River network saturation concept: factors influencing the balance of biogeochemical supply and demand of river networks
River network saturation concept: factors influencing the balance of biogeochemical supply and demand of river networks
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DOI：
10.1007/s10533-018-0488-0
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发表时间：
2018-08
期刊：
影响因子：
4
通讯作者：
W. Wollheim;Susana Bernal;Douglas A. Burns;J. Czuba;Charles T. Driscoll;Amy T. Hansen;Robert T. Hensley;Jacob D. Hosen;Shreeram Inamdar;S. Kaushal;L. Koenig;YueHan Lu;A. Marzadri;Peter A. Raymond;Durelle T. Scott;R. J. Stewart;P. Vidon;Ellen Wohl
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作者：
W. Wollheim;Susana Bernal;Douglas A. Burns;J. Czuba;Charles T. Driscoll;Amy T. Hansen;Robert T. Hensley;Jacob D. Hosen;Shreeram Inamdar;S. Kaushal;L. Koenig;YueHan Lu;A. Marzadri;Peter A. Raymond;Durelle T. Scott;R. J. Stewart;P. Vidon;Ellen Wohl
河流网络改变了从陆地到海洋的物质转移。了解不同的气体，溶解和颗粒成分的调节这一功能的因素是至关重要的，以量化气候和土地利用变化的局部和全球影响。我们提出了河流网络饱和度（RNS）的概念，作为一个概括的河流网络调节的物质通量下降，随着流量的增加，由于在网络尺度上的供需之间的不平衡。在较高的流量条件下，河流网络有趋于饱和（供给大于需求）的趋势，因为供给的增加快于汇的过程。然而，饱和发生时的流量阈值取决于多种因素，包括给定成分的固有过程速率和静水沃茨的丰度，如湖泊、池塘、水库和河流网络内的河流湿地。随着供应的增加，网络规模的饱和最初受到下游水生生态系统先前未满足的需求的限制。RNS概念描述了河流网络功能的总体趋势，可用于比较河流网络中不同组成部分的命运。使用嵌套的原位高频传感器和空间广泛的天气技术的新方法提供了在不同环境中测试RNS概念的可能性。更好地了解河流网络在何时何地对不同成分饱和，将有助于将水生功能外推到更广泛的空间尺度，从而提供有关河流功能对大陆元素周期影响的信息，并有助于确定政策优先事项。
River networks modify material transfer from land to ocean. Understanding the factors regulating this function for different gaseous, dissolved, and particulate constituents is critical to quantify the local and global effects of climate and land use change. We propose the River Network Saturation (RNS) concept as a generalization of how river network regulation of material fluxes declines with increasing flows due to imbalances between supply and demand at network scales. River networks have a tendency to become saturated (supply ≫ demand) under higher flow conditions because supplies increase faster than sink processes. However, the flow thresholds under which saturation occurs depends on a variety of factors, including the inherent process rate for a given constituent and the abundance of lentic waters such as lakes, ponds, reservoirs, and fluvial wetlands within the river network. As supply increases, saturation at network scales is initially limited by previously unmet demand in downstream aquatic ecosystems. The RNS concept describes a general tendency of river network function that can be used to compare the fate of different constituents among river networks. New approaches using nested in situ high-frequency sensors and spatially extensive synoptic techniques offer the potential to test the RNS concept in different settings. Better understanding of when and where river networks saturate for different constituents will allow for the extrapolation of aquatic function to broader spatial scales and therefore provide information on the influence of river function on continental element cycles and help identify policy priorities.