Hyporheic Passive Flux Meters Reveal Inverse Vertical Zonation and High Seasonality of Nitrogen Processing in an Anthropogenically Modified Stream (Holtemme, Germany)
Hyporheic Passive Flux Meters Reveal Inverse Vertical Zonation and High Seasonality of Nitrogen Processing in an Anthropogenically Modified Stream (Holtemme, Germany)
复制标题
潜流被动通量计揭示了人为改造流中氮处理的逆垂直分区和高季节性（德国霍尔特姆）
DOI：
10.1002/2017wr020709
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发表时间：
2017
影响因子：
5.4
通讯作者：
D. Borchardt
中科院分区：
文献类型：
--
作者：
J. V. Kunz;M. Annable;Suresh G. Rao;M. Rode;D. Borchardt
氮和其他生物反应性溶质在流水潜流区的转化和保留有助于提供重要的生态系统服务。然而，密集的农业或城市土地利用、养分负荷升高、流量变化、河岸砍伐和渠道化对潜流区溶质源汇行为的天气影响在很大程度上仍然是未表征和未量化的。因此，我们使用一种新的监测方法研究了经过水貌和化学修饰的河段的养分动态，该方法可以同时测量通过河流地下屏蔽区域的养分和水通量（潜流被动通量计，HPFM）。利用 HPFM，我们直接评估了早春和仲夏期间不同温度和排放情况下的时间积分侧向渗流硝酸盐通量。与我们的预期相反，较高的流量流量与显着较低的潜流汇率同时发生。虽然在具有自然形态的溪流中，床形引起的交换通常随着地表流量的增加而增加，但地下水位的影响在该河段中占主导地位。此外，与受影响较小的环境相比，随着深度的增加，底物逐渐耗尽，地下的代谢率降低，我们发现潜流带的上层而不是中间层是养分周转的热点。总体而言，研究地点的潜流带部分充当硝酸盐源，部分充当汇。常用的决定因素氧化还原态和停留时间都无法解释这种源或汇函数。我们的结果提供了明确的证据，可以仔细地将潜流带过程的知识从“自然”系统转移到经过人类学改造的河流。
Transformation and retention of nitrogen and other biologically reactive solutes in the hyporheic zones of running water contribute to an essential ecosystem service. However, the synoptic impact of intense agricultural or urban land‐uses, elevated nutrient loading, flow alterations, riparian clear‐cutting, and channelization on the source‐sink behavior of solutes in hyporheic zones remains largely uncharacterized and unquantified. Therefore, we studied nutrient dynamics in a hydromorphologically and chemically modified stream reach using a new monitoring approach allowing the simultaneous measurement of nutrient and water flux through a screened area in the subsurface of rivers (hyporheic passive flux meter, HPFM). With HPFMs we directly assessed time‐integrated lateral hyporheic nitrate fluxes during early spring and midsummer covering different temperature and discharge regimes. Contrary to our expectations, higher stream discharge coincided with substantially lower hyporheic exchange rates. While in streams featuring a natural morphology, bed form induced exchange commonly increases with surface flow, the influence of groundwater level was dominant in this reach. Furthermore, in contrast to less impacted environments, where progressive substrate depletion with depths reduces metabolic rates in the subsurface, we identified not the upper, but the intermediate layer of the hyporheic zone as hot spot of nutrient turnover. Overall, the hyporheic zone at the study site functioned partly as nitrate source, partly as a sink. Neither of the commonly used determinants redox state and residence time could explain this source or sink function. Our results give clear evidence to carefully transfer the knowledge of hyporheic zone processes from “natural” systems to anthropologically modified streams.
影响因子：
4.5
作者：
K. Lansdown;M. Trimmer;C. Heppell;F. Sgouridis;Sami Ullah;A. Heathwaite;A. Binley;Hao Zhang
通讯作者：
K. Lansdown;M. Trimmer;C. Heppell;F. Sgouridis;Sami Ullah;A. Heathwaite;A. Binley;Hao Zhang
影响因子：
3
作者：
Kamjunke, Norbert;Buettner, Olaf;Weitere, Markus
通讯作者：
Weitere, Markus