The permeability of sediments at the sediment–water interface is an important control on several stream ecosystem services. It is well known that streambed permeability varies over several orders of magnitude, however, the environmental processes influencing this variation have received little attention. This review synthesizes the state-of-art knowledge and gaps in our understanding of the key physical and biological processes which can potentially modify the streambed permeability. These processes include—(a) physical clogging due to fine sediments, (b) biological clogging due to microbial biomass, and (c) sediment reworking by in-stream fauna. We highlight that the role of biotic processes (bioclogging and sediment reworking processes) in modifying the streambed permeability has not been investigated in detail. We emphasize that complex feedback mechanisms exist between these abiotic and biotic processes, and an interdisciplinary framework is necessary to achieve a holistic understanding of the spatio-temporal variability in streambed permeability. To this end, we propose to develop a conceptual model for streambed evolution after a disturbance (e.g. floods) as this model could be valuable in comprehending the dynamics of permeability. We also outline the challenges associated with developing a widely applicable streambed evolution model. Nonetheless, as a way forward, we present a possible scenario for the evolution of a streambed following a high flow event based on the trajectory of responses of the above-mentioned environmental processes. Finally, we suggest future research directions that could assist in improving the fundamental understanding of the clogging and sediment reworking processes and consequently of the dynamics of streambed permeability.

中文翻译：

---

将河床理解为复杂系统：审查影响河床渗透率的多种相互作用的环境过程

沉积物-水界面处沉积物的渗透性是对几种河流生态系统服务的重要控制。众所周知，河床渗透率在几个数量级上变化，然而，影响这种变化的环境过程很少受到关注。这篇综述综合了我们对可能改变河床渗透性的关键物理和生物过程的理解中的最新知识和差距。这些过程包括——(a) 细小沉积物造成的物理堵塞，(b) 微生物生物量造成的生物堵塞，以及 (c) 河流中动物群的沉积物再加工。我们强调，尚未详细研究生物过程（生物堵塞和沉积物再加工过程）在改变河床渗透率方面的作用。我们强调这些非生物和生物过程之间存在复杂的反馈机制，需要一个跨学科的框架来全面了解河床渗透率的时空变异性。为此，我们建议开发一个扰动（例如洪水）后河床演化的概念模型，因为该模型在理解渗透率动态方面可能很有价值。我们还概述了与开发广泛适用的河床演化模型相关的挑战。尽管如此，作为前进的方向，我们提出了基于上述环境过程响应轨迹的高流量事件后河床演变的可能情景。最后，