Flow Extremes as Spatiotemporal Control Points on River Solute Fluxes and Metabolism
Flow Extremes as Spatiotemporal Control Points on River Solute Fluxes and Metabolism
复制标题
流量极值作为河流溶质通量和代谢的时空控制点
DOI：
10.1029/2018jg004738
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发表时间：
2019
期刊：
影响因子：
--
通讯作者：
M. Cohen
中科院分区：
文献类型：
--
作者：
R. Hensley;Lily Kirk;M. Spangler;M. Gooseff;M. Cohen
洪水是控制集水区溶质出口的主要因素。相比之下，干旱等低流量时期是生物地球化学处理的潜在主要控制点，增强了溶质浓度、溪流代谢和养分吸收的时空变化。利用互补时间序列（即欧拉参照系）和纵向剖面（即拉格朗日参照系），我们研究了圣达菲河下游（佛罗里达州，美国）溶质通量和代谢的时空变化的水文控制，在那里，高度着色的地表水与来自泉水的异常清澈的地下水混合在一起。测量结果表明，地下水输入量占总流量(Q)的比例从<1%（极端洪水期间）到86%（极端干旱期间）不等。大多数溶质的质量输运以高Q期为主。大多数溶质C - Q关系在地表和地下水优势之间的过渡附近显示出统计学上显著的斜率断点。特别是，控制水柱光衰减的参数在中值Q以上是化学平衡的，而在低Q时则显著降低。因此，河流代谢和同化硝态氮（NO3−）吸收在高Q时持续受到抑制，在低Q时持续增强，且对除水柱透光率以外的驱动因素的响应具有更大的变异性。低Q时，由于地下水流入和生物地球化学过程的影响，溶质浓度的空间变异也增强了。对比参考框架得到了高Q下输运优势的确凿证据，这抑制了时空异质性。相比之下，低Q周期使得局部混合控制溶质浓度和高代谢速率以及增加时空变异性的营养物质处理成为可能。
Floods are dominant controls on export of solutes from catchments. In contrast, low‐flow periods such as droughts are potentially dominant control points for biogeochemical processing, enhancing spatiotemporal variation in solute concentrations, stream metabolism, and nutrient uptake. Using complementary time series (i.e., an Eulerian reference frame) and longitudinal profiling (i.e., a Lagrangian reference frame), we investigated hydrologic controls on temporal and spatial variation in solute flux and metabolism in the Lower Santa Fe River (FL, USA), where highly colored surface water mixes with exceptionally clear groundwater from springs. Gage measurements suggest groundwater inputs ranged from <1% (during extreme floods) to 86% (during extreme drought) of total discharge (Q). Mass transport of most solutes was dominated by high‐Q periods. Most solute C‐Q relationships exhibited statistically significant slope breakpoints near the transition between surface and groundwater dominance. In particular, parameters controlling water column light attenuation were chemostatic above median Q but markedly reduced at low Q. As a result, river metabolism and assimilatory nitrate (NO3−) uptake were consistently suppressed at high Q and enhanced at low Q, with greater variability in response to drivers other than water column light transmittance. Spatial variation in solute concentrations was also enhanced at low Q, induced by discrete groundwater inflow and biogeochemical processing along the reach. Contrasting reference frames yielded corroborative evidence for transport dominance at high Q, which damps spatiotemporal heterogeneity. In contrast, low‐Q periods enable localized mixing controls on solute concentrations and high rates of metabolism and nutrient processing that increase spatiotemporal variability.
影响因子：
4
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
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
影响因子：
3.7
作者：
Bernhardt, Emily S.;Blaszczak, Joanna R.;Seybold, Erin C.
通讯作者：
Seybold, Erin C.