Terminal electron accepting processes in the alluvial sediments of a headwater stream
Terminal electron accepting processes in the alluvial sediments of a headwater stream
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源头河流冲积沉积物中的终端电子接受过程
DOI：
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发表时间：
2000
影响因子：
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通讯作者：
Michael E. Campana
中科院分区：
文献类型：
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作者：
J. Morrice;C. Dahm;H. Valett;P. V. Unnikrishna;Michael E. Campana
地下水-河流水（GW-SW）交错带是河流地表水和地下水之间的界面，其化学通量受地下水-河流水（GW-SW）交错带中的地球化学过程的影响。缺氧环境中有机碳呼吸作用的末端电子接受过程（TEAP）可能对营养动态和水化学产生强烈影响。在安装在地表流下方的垂直嵌套威尔斯井网络和水源集水区的近流含水层中，测量了氧化和还原形式的终端电子受体（溶解的O2、NO3−、Fe 2+、SO 42 −和CH 4）的浓度。在地表和地下水环境的一级山地流进行了示踪剂添加实验，以表征河流和含水层之间的水文通量，并量化终端电子受体（NO3-和SO 42-）的GW-SW交错带的生态系统保留。硫酸盐保留在低渗和地下水环境中都很明显。重要的氧化还原敏感性溶质的分布变化可预见的变化与水的水文停留时间在GW-SW交错带。结果表明，一个强大的水文控制的TEAP和生态系统保留的生物重要的溶质在GW-SW的过渡带相关的特性GW-SW混合和滞留时间的水在hyporheic区。
Chemical fluxes between catchments and streams are influenced by biogeochemical processes in the groundwater–stream water (GW–SW) ecotone, the interface between stream surface water and groundwater. Terminal electron accepting processes (TEAPs) that are used in respiration of organic C in anoxic environments may have a strong effect on nutrient dynamics and water chemistry. Concentrations of oxidized and reduced forms of terminal electron acceptors (dissolved O2, NO3−, Fe2+, SO42−, and CH4) were measured in networks of vertically nested wells installed beneath the surface stream and in the near-stream aquifer of a headwater catchment. Tracer addition experiments were conducted in surface and groundwater environments of a 1st-order montane stream to characterize hydrologic fluxes between the stream and aquifer, and to quantify ecosystem retention of terminal electron acceptors (NO3− and SO42−) in the GW–SW ecotone. Sulfate retention was evident in both hyporheic and groundwater environments. Distribution of important redox sensitive solutes varied predictably with changing hydrologic residence time of water in the GW–SW ecotone. Results suggest a strong hydrologic control of TEAPs and ecosystem retention of biologically important solutes in the GW–SW ecotone related to characteristics of GW–SW mixing and residence time of water in the hyporheic zone.