Sea-level rise is a threat to coastal ecosystems, which have important conservation and economic value. While marsh response to sea-level rise has been well characterized for perennially open estuaries, bar-built intermittently-closed estuaries and their sea-level rise response are seldom addressed in the literature – despite being common globally. We seek to advance the conceptual understanding of sea-level rise response of marshes by incorporating the unique nature of intermittently-closed estuaries in a marsh model. We hypothesize that intermittently-closed-estuary marshes may be more resilient to sea-level rise than open-estuary marshes due to greater initial elevation capital and higher accretion rates due to closure events. Using California, USA as a case study, spatial analysis shows that marshes in intermittently-closed-estuaries had significantly greater elevations (x̄ = 1.93 m ± 0.2 standard error, n = 14) than marshes in permanently open estuaries (x̄ = 0.94 m ± 0.1 standard error, n = 8; P = 0.003). We then used a process-based model to determine marsh elevation change under 840 simulated responses to sea-level rise to 2100. Our modeling shows that regular annual mouth closure can promote accretion rates and increase marsh elevations fast enough to match even high rates of sea-level rise, as fluvial sediment pulses can be captured in the estuary. Modeled suspended sediment concentration had the strongest effect on accretion, followed by probability of annual mouth closure. Intermittently closed estuaries are critical environments where marshes may be sustained under high rates of sea-level rise, thus reducing the anticipated global loss of these important ecosystems. Our results begin to fill an important gap in the knowledge about marsh accretion and identify research needs to inform coastal management.

海平面上升是对沿海生态系统的威胁，沿海生态系统具有重要的保护和经济价值。尽管常年开放的河口对沼泽地对海平面上升的反应具有很好的特征，但尽管在全球范围内普遍存在，但在文献中很少涉及条形断断续续的条形河口及其海平面上升的反应。我们试图通过将间歇关闭的河口的独特性质整合到沼泽模型中来提高对沼泽地海平面上升响应的概念理解。我们假设间歇性封闭河口沼泽地对海平面上升的抵抗力可能比开放河口沼泽地大，这是由于更大的初始标高资本和较高的封闭事件引起的增生率。以美国加利福尼亚为例，空间分析表明，间歇性封闭河口的沼泽标高（x̄= 1.93 m±0.2标准误差，n = 14）比永久开放河口的沼泽标高（x̄= 0.94 m±0.1标准误差，n = 8; P = 0.003）。然后，我们使用了基于过程的模型来确定在840种模拟海平面上升到2100年的响应下的沼泽高程变化。我们的模型显示，定期的年度封海活动可以促进增生速率并快速增加沼泽高程，甚至可以与高海速相提并论。水位上升，因为在河口可以捕获到河流沉积物脉动。模拟的悬浮沉积物浓度对吸积的影响最大，其次是每年闭口的可能性。间歇性封闭的河口是至关重要的环境，在高海平面上升速率下沼泽可能会持续存在，从而减少了这些重要生态系统的预期全球损失。我们的结果开始填补有关沼泽积聚知识的重要空白，并确定研究需求以为沿海管理提供参考。