An accelerating global rate of sea level rise (SLR), coupled with direct human impacts to coastal watersheds and shorelines, threatens the continued survival of salt marshes. We developed a new landscape‐scale numerical model of salt marsh evolution and applied it to marshes in the Plum Island Estuary (Massachusetts, U.S.A.), a sediment‐deficient system bounded by steep uplands. To capture complexities of vertical accretion across the marsh platform, we employed a novel approach that incorporates spatially variable suspended sediment concentrations and biomass of multiple plant species as functions of elevation and distance from sediment sources. The model predicts a stable areal extent of Plum Island marshes for a variety of SLR scenarios through 2100, where limited marsh drowning is compensated by limited marsh migration into adjacent uplands. Nevertheless, the model predicts widespread conversion of high marsh vegetation to low marsh vegetation, and accretion deficits that indicate eventual marsh drowning. Although sediment‐deficient marshes bounded by steep uplands are considered extremely vulnerable to SLR, our results highlight that marshes with high elevation capital can maintain their areal extent for decades to centuries even under conditions in which they will inevitably drown.

中文翻译：

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在马萨诸塞州沉积物匮乏的梅花岛河口模拟长期盐沼对海平面上升的响应

全球海平面上升速度（SLR）的加快，再加上人类对沿海流域和海岸线的直接影响，威胁着盐沼的持续生存。我们开发了一种新的盐沼演化的景观尺度数值模型，并将其应用于梅子岛河口（美国马萨诸塞州）的沼泽，这是一个由陡峭山地包围的缺乏泥沙的系统。为了捕获整个沼泽平台上垂直沉积物的复杂性，我们采用了一种新颖的方法，该方法结合了空间可变的悬浮沉积物浓度和多种植物物种的生物量，作为海拔和与沉积物来源的距离的函数。该模型预测，到2100年，对于各种SLR场景，梅花岛沼泽的面积都将保持稳定，其中有限的沼泽溺水可以通过有限的沼泽向邻近山地的迁移来补偿。然而，该模型预测高沼泽植被将普遍转化为低沼泽植被，并出现增生赤字，这表明沼泽最终会被淹死。尽管被陡峭山地包围的缺乏沉积物的沼泽被认为极易受到SLR的破坏，但我们的研究结果表明，即使在不可避免的淹没条件下，高海拔资本的沼泽也可以维持其面积数十年至几个世纪。