Mangroves can store more sediment organic carbon (SOC) than freshwater and salt marshes. Understanding how mangroves have responded to historical sea-level rise (SLR) is fundamental to assessing their resilience and capacity to store carbon as SLR accelerates. We quantified landscape-level temporal and spatial trends in historical coastal wetland sediment accumulation and associated SOC content (i.e., storage) along coastal-to-inland gradients in Southeast Florida. The observed trends were transgressive and attributed to the historical rise in sea level. Our results indicate an overall significant increase in the SOC content of the historic wetland sediment succession caused by the vertical accumulation and landward migration of carbon-rich mangrove-dominated plant communities (mean = 0.08 g cm⁻³) into and over carbon-poor wet prairie plant communities (mean = 0.02 g cm⁻³). The observed historical increase in SOC is predicted to diminish over time as the difference between rates of SLR and vertical sediment accumulation increases and because the landward migration of mangrove-dominated plant communities is now obstructed by a shore-parallel flood-control levee. These results are likely to unfold in other low-latitude coastal wetlands where they are sandwiched between rising seas and an urbanized landscape.

与淡水和盐沼相比，红树林可以存储更多的沉积物有机碳（SOC）。了解红树林如何应对历史海平面上升（SLR）是评估其随着SLR加速而恢复的能力和碳储存能力的基础。我们量化了佛罗里达东南部沿海沿陆向内陆梯度的历史沿岸湿地沉积物堆积的景观水平时空趋势以及相关的SOC含量（即储存）。观察到的趋势是海侵性的，并且归因于海平面的历史上升。我们的结果表明，由于富含碳的红树林为主的植物群落的垂直积累和向陆迁移，导致历史湿地沉积物演替的SOC含量总体上显着增加（平均值= 0.08 g cm ^-3））进入低碳湿草原植物群落（平均= 0.02 g cm ^-3）。随着SLR速率和垂直沉积物积累之间的差异增加，并且由于红树林为主的植物群落的陆上迁徙现在受到岸上平行的防洪堤坝的阻碍，SOC的观察到的历史增长预计将随着时间的推移而减少。这些结果可能会在其他低纬度沿海湿地中展开，这些湿地将它们夹在海平面上升和城市化景观之间。