Dataset: Temporal variability of carbon and nutrient burial, sediment accretion, and mass accumulation over the past century in a carbonate platform mangrove forest of the Florida Everglades

The objective of this research was to measure temporal variability in accretion and mass sedimentation rates (including organic carbon (OC), total nitrogen (TN), and total phosphorous (TP)) from the past century in a mangrove forest on the Shark River in Everglades National Park, USA. The 210Pb Constant Rate of Supply model was applied to six soil cores to calculate annual rates over the most recent 10, 50, and 100 year time spans. Our results show that rates integrated over longer timeframes are lower than those for shorter, recent periods of observation. Additionally, the substantial spatial variability between cores over the 10 year period is diminished over the 100 year record, raising two important implications. First, a multiple-decade assessment of soil accretion and OC burial provides a more conservative estimate and is likely to be most relevant for forecasting these rates relative to long-term processes of sea level rise and climate change mitigation. Second, a small number of sampling locations are better able to account for spatial variability over the longer periods than for the shorter periods. The site average 100 year OC burial rate, 123 +/- 19 (standard deviation) g m^-2 yr^-1, is low compared with global mangrove values. High TN and TP burial rates in recent decades may lead to increased soil carbon remineralization, contributing to the low carbon burial rates. Finally, the strong correlation between OC burial and accretion across this site signals the substantial contribution of OC to soil building in addition to the ecosystem service of CO2 sequestration.

本研究以美国大沼泽地国家公园鲨鱼河沿岸的红树林湿地为研究对象，旨在量化近一个世纪以来该区域土壤加积速率与沉积物堆积速率（涵盖有机碳（OC）、总氮（TN）与总磷（TP））的时间变异性。本研究采用210Pb恒定补给速率模型，对6个土壤岩芯进行分析，以计算近10年、50年及100年三个时间尺度的年际速率。研究结果显示，较长时间尺度下整合得到的速率低于近期较短观测时段的速率。此外，10年时间尺度下岩芯间显著的空间异质性，在100年的观测记录中有所减弱，这带来两点重要启示。其一，针对土壤加积与OC埋藏的数十年尺度评估，可得到更为保守的估算结果，且相较于海平面上升与气候变化缓解的长期过程，该估算结果与上述过程的速率预测更为相关。其二，相较于较短时间尺度，少量采样点位即可在较长时间尺度上较好地反映空间异质性。该样点的百年尺度OC埋藏速率平均值为123±19（标准差）g·m⁻²·yr⁻¹，相较于全球红树林的相关数值处于较低水平。近数十年间较高的TN与TP埋藏速率，可能会增强土壤碳的矿化作用，进而导致较低的碳埋藏速率。最后，该样点内OC埋藏速率与沉积加积速率间存在显著相关性，这表明OC除了具备CO₂封存的生态系统服务功能外，还对土壤构建具有重要贡献。