Surface-groundwater interactions in intermittent rivers and ephemeral streams (IRES), waterways which do not flow year-round, are spatially and temporally dynamic because of alternations between flowing, non-flowing and dry hydrological states. Interactions between surface and groundwater often create mixing zones with distinct redox gradients, potentially driving high rates of carbon and nutrient cycling. Yet a complete understanding of how underlying biogeochemical processes across surface-groundwater flowpaths in IRES differ among various hydrological states remains elusive. Here, we present a conceptual framework relating spatial and temporal hydrological variability in surface water-groundwater interactions to biogeochemical processing hotspots in IRES. We combine a review of theIRES biogeochemistry literature with concepts of IRES hydrogeomorphology to: (i) outline common distinctions among hydrological states in IRES; (ii) use these distinctions, together with considerations of carbon, nitrogen, and phosphorus cycles within IRES, to predict the relative potential for biogeochemical processing across different reach-scale processing zones (flowing water, fragmented pools, hyporheic zones, groundwater, and emerged sediments); and (iii) explore the potential spatial and temporal variability of carbon and nutrient biogeochemical processing across entire IRES networks. Our approach estimates the greatest reach-scale potential for biogeochemical processing when IRES reaches are fragmented into isolated surface water pools, and highlights the potential of relatively understudied processing zones, such as emerged sediments. Furthermore, biogeochemical processing in fluvial networks dominated by IRES is likely more temporally than spatially variable. We conclude that biogeochemical research in IRES would benefit from focusing on interactions between different nutrient cycles, surface-groundwater interactions in non-flowing states, and consideration of fluvial network architecture. Our conceptual framework outlines opportunities to advance studies and expand understanding of biogeochemistry in IRES.

由于流动、不流动和干燥水文状态之间的交替，断断续续的河流和短暂的河流 (IRES) 中的地表水相互作用是全年不流动的水道，在空间和时间上是动态的。地表水和地下水之间的相互作用通常会产生具有不同氧化还原梯度的混合区，可能会推动碳和养分循环的高速率。然而，对 IRES 中地表地下水流动路径的潜在生物地球化学过程在不同水文状态之间有何不同的完整理解仍然难以捉摸。在这里，我们提出了一个概念框架，将地表水-地下水相互作用的空间和时间水文变化与 IRES 中的生物地球化学处理热点相关联。我们将 IRES 生物地球化学文献的综述与 IRES 水文地貌学的概念结合起来：(i) 概述 IRES 中水文状态之间的共同区别；(ii) 使用这些区别，连同对 IRES 内碳、氮和磷循环的考虑，预测不同河段规模加工区（流水、破碎池、潜流区、地下水和涌出水）的生物地球化学加工的相对潜力沉积物）；(iii) 探索整个 IRES 网络中碳和养分生物地球化学处理的潜在时空变异性。我们的方法估计了当 IRES 河段被分割成孤立的地表水池时生物地球化学处理的最大河段规模潜力，并突出了研究相对不足的处理区的潜力，比如出现的沉积物。此外，由 IRES 主导的河流网络中的生物地球化学处理可能在时间上比空间上的变化更大。我们得出的结论是，IRES 中的生物地球化学研究将受益于关注不同营养循环之间的相互作用、非流动状态下的地表地下水相互作用以及对河流网络结构的考虑。我们的概念框架概述了在 IRES 中推进研究和扩大对生物地球化学的理解的机会。并考虑河流网络架构。我们的概念框架概述了在 IRES 中推进研究和扩展对生物地球化学的理解的机会。并考虑河流网络架构。我们的概念框架概述了在 IRES 中推进研究和扩大对生物地球化学的理解的机会。