Impacts of Evaporation‐Induced Groundwater Upwelling on Mixing Dynamics in Shallow Wetlands
Impacts of Evaporation‐Induced Groundwater Upwelling on Mixing Dynamics in Shallow Wetlands
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DOI：
10.1029/2023gl104642
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发表时间：
2023-08
影响因子：
5.2
通讯作者：
X. Geng;M. Boufadel;Hailong Li;Viravid Na Nagara;Kenneth Lee
中科院分区：
文献类型：
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作者：
X. Geng;M. Boufadel;Hailong Li;Viravid Na Nagara;Kenneth Lee
地下水混合动力学在浅层湿地生态地球化学循环中起着至关重要的作用。在本文中，我们进行了地下水模拟研究蒸发和局部非均匀性的混合动力学在浅水湿地沉积物的综合影响。结果表明，蒸发导致地下水和溶质从深层沉积物上升到表面。当溶质到达表面时，蒸发增强了表面附近溶质的积累，导致溶质浓度高于深层沉积物。流动拓扑图显示，局部异质性主要沿沿着优先流动路径产生空间上不同的混合模式。地表蒸发通过异质沉积物引起的地下水上涌可能会产生明显的混合热点，这些混合热点在空间上与大尺度水力梯度驱动的横向优先流产生的混合热点不同，这增强了地下的整体混合。这些发现对湿地生态地球化学过程具有重要意义。
Groundwater mixing dynamics play a crucial role in the biogeochemical cycling of shallow wetlands. In this paper, we conducted groundwater simulations to investigate the combined effects of evaporation and local heterogeneity on mixing dynamics in shallow wetland sediments. The results show that evaporation causes groundwater and solutes to upwell from deep sediments to the surface. As the solute reaches the surface, evaporation enhances the accumulation of the solute near the surface, resulting in a higher solute concentration than in deep sediments. Mapping of flow topology reveals that local heterogeneity generates spatially varied mixing patterns mainly along preferential flow pathways. The upwelling of groundwater induced by surface evaporation through heterogeneous sediments is likely to create distinct mixing hotspots that differ spatially from those generated by lateral preferential flows driven by large‐scale hydraulic gradients, which enhances the overall mixing in the subsurface. These findings have strong implications for biogeochemical processing in wetlands.