Salt marshes are valuable ecosystems that must trap sediments and accrete in order to counteract the deleterious effect of sea level rise. Previous studies have shown that the capacity of marshes to build up vertically depends on both autogenous and exogenous processes including ecogeomorphic feedbacks and sediment supply from in‐land and coastal ocean. There have been numerous efforts to quantify the role played by the sediments coming from marsh edge erosion on the resistance of salt marshes to sea level rise. However, the majority of existing studies investigating the interplay between lateral and vertical dynamics use simplified modeling approaches, and they do not consider that marsh retreat can affect the regional‐scale hydrodynamics and sediment retention in back‐barrier basins. In this study, we evaluated the fate of the sediments originating from marsh lateral loss by using high‐resolution numerical model simulations of Jamaica Bay, a small lagoonal estuary located in New York City. Our findings show that up to 42% of the sediment released during marsh edge erosion deposits on the shallow areas of the basin and over the vegetated marsh platforms, contributing positively to the sediment budget of the remaining salt marshes. Furthermore, we demonstrate that with the present‐day sediment supply from the ocean, the system cannot keep pace with sea level rise even accounting for the sediment liberated in the bay through marsh degradation. Our study highlights the relevance of multiple sediment sources for the maintenance of the marsh complex.

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泻湖型河口沼泽沉积物的动力学

盐沼是宝贵的生态系统，必须捕获沉积物并积聚以抵消海平面上升的有害影响。先前的研究表明，沼泽的垂直堆积能力取决于自生过程和外生过程，包括生态地貌反馈和内陆和沿海海洋的沉积物供应。已经进行了许多努力来量化由沼泽边缘侵蚀引起的沉积物对盐沼对海平面上升的抵抗作用。但是，大多数研究横向和纵向动力学之间相互作用的现有研究都使用简化的建模方法，并且他们并不认为沼泽撤退会影响后屏障盆地的区域尺度水动力和沉积物滞留。在这个研究中，我们通过使用位于纽约市的一个小泻湖河口牙买加湾的高分辨率数值模型模拟，评估了沼泽侧向损失造成的沉积物的命运。我们的发现表明，在沼泽边缘侵蚀期间，高达42％的沉积物释放到盆地的浅水区和植被沼泽平台上，对剩余盐沼的沉积物预算有积极贡献。此外，我们证明，随着当今海洋中沉积物的供应，即使考虑到沼泽退化造成的海湾沉积物释放，该系统也无法跟上海平面上升的步伐。我们的研究强调了多种沉积物源与沼泽综合体维护的相关性。位于纽约市的一个小泻湖河口。我们的发现表明，在沼泽边缘侵蚀期间，高达42％的沉积物释放到盆地的浅水区和植被沼泽平台上，对剩余盐沼的沉积物预算有积极贡献。此外，我们证明，随着当今海洋中沉积物的供应，即使考虑到沼泽退化造成的海湾沉积物释放，该系统也无法跟上海平面上升的步伐。我们的研究强调了多种沉积物源与沼泽综合体维护的相关性。位于纽约市的一个小泻湖河口。我们的发现表明，在沼泽边缘侵蚀期间，高达42％的沉积物释放到盆地的浅水区和植被沼泽平台上，对剩余盐沼的沉积物预算有积极贡献。此外，我们证明，随着当今海洋中沉积物的供应，即使考虑到沼泽退化造成的海湾沉积物释放，该系统也无法跟上海平面上升的步伐。我们的研究强调了多种沉积物源与沼泽综合体维护的相关性。对剩余盐沼的沉积物预算有积极贡献。此外，我们证明，随着当今海洋中沉积物的供应，即使考虑到沼泽退化造成的海湾沉积物释放，该系统也无法跟上海平面上升的步伐。我们的研究强调了多种沉积物源与沼泽综合体维护的相关性。对剩余盐沼的沉积物预算有积极贡献。此外，我们证明，随着当今海洋中沉积物的供应，即使考虑到沼泽退化造成的海湾沉积物释放，该系统也无法跟上海平面上升的步伐。我们的研究强调了多种沉积物源与沼泽综合体维护的相关性。