Yang Judy Q
St. Anthony Falls Laboratory, Department of Civil, Environmental, and Geo-Engineering, University of Minnesota Twin Cities, MN, USA.
Environ Sci Ecotechnol. 2024 May 10;21:100429. doi: 10.1016/j.ese.2024.100429. eCollection 2024 Sep.
In-channel vegetation is ubiquitous in aquatic environments and plays a critical role in the fate and transport of solutes and particles in aquatic ecosystems. Recent studies have advanced our understanding of the role of vegetation in solute flow and particle transport in aquatic ecosystems. This review summarizes these papers and discusses the impacts of emergent and rigid vegetation on the surface flow, the advection and dispersion of solutes, suspended load transport, bedload transport, and hyporheic exchange. The two competing effects of emergent vegetation on the above transport processes are discussed. On the one hand, emergent vegetation reduces mean flow velocity at the same surface slope, which reduces mass transport. On the other hand, at the same mean flow velocity, vegetation generates turbulence, which enhances mass transport. Mechanistic understanding of these two competing effects and predictive equations derived from laboratory experiments are discussed. Predictive equations for the mean flow velocity and turbulent kinetic energy inside an emergent vegetation canopy are derived based on force and energy balance. The impacts of emergent vegetation on the advection-dispersion process, the suspended load and bedload transport, and the hyporheic exchange are summarized. The impacts of other vegetation-related factors, such as vegetation morphology, submergence, and flexibility, are briefly discussed. The role of vegetation in transporting other particles, such as micro- and macro-plastics, is also briefly discussed. Finally, suggestions for future research directions are proposed to advance the understanding of the dynamic interplays among natural vegetation, flow dynamics, and sedimentary processes.
河道内植被在水生环境中普遍存在，并且在水生生态系统中溶质和颗粒的归宿与输运过程中发挥着关键作用。近期的研究增进了我们对植被在水生生态系统中溶质流动和颗粒输运作用的理解。本综述总结了这些论文，并讨论了挺水植被和刚性植被对地表水流动、溶质的平流与扩散、悬移质输运、推移质输运以及渗流交换的影响。文中讨论了挺水植被对上述输运过程的两种相互竞争的效应。一方面，在相同的水面坡度下，挺水植被会降低平均流速，从而减少物质输运。另一方面，在相同的平均流速下，植被会产生湍流，进而增强物质输运。文中讨论了对这两种相互竞争效应的机理理解以及从实验室实验得出的预测方程。基于力和能量平衡，推导了挺水植被冠层内平均流速和湍动能的预测方程。总结了挺水植被对平流 - 扩散过程、悬移质和推移质输运以及渗流交换的影响。简要讨论了其他与植被相关的因素，如植被形态、淹没程度和柔韧性的影响。还简要讨论了植被在运输其他颗粒（如微塑料和大塑料）方面的作用。最后，提出了未来研究方向的建议，以增进对自然植被、水流动力学和沉积过程之间动态相互作用的理解。
