Smithsonian Environmental Research Center, Edgewater, USA.
USGS, National Research Program, Water Resources Division, Menlo Park, USA.
Sci Rep. 2018 Jun 21;8(1):9478. doi: 10.1038/s41598-018-26948-7.
Tidal wetlands produce long-term soil organic carbon (C) stocks. Thus for carbon accounting purposes, we need accurate and precise information on the magnitude and spatial distribution of those stocks. We assembled and analyzed an unprecedented soil core dataset, and tested three strategies for mapping carbon stocks: applying the average value from the synthesis to mapped tidal wetlands, applying models fit using empirical data and applied using soil, vegetation and salinity maps, and relying on independently generated soil carbon maps. Soil carbon stocks were far lower on average and varied less spatially and with depth than stocks calculated from available soils maps. Further, variation in carbon density was not well-predicted based on climate, salinity, vegetation, or soil classes. Instead, the assembled dataset showed that carbon density across the conterminous united states (CONUS) was normally distributed, with a predictable range of observations. We identified the simplest strategy, applying mean carbon density (27.0 kg C m), as the best performing strategy, and conservatively estimated that the top meter of CONUS tidal wetland soil contains 0.72 petagrams C. This strategy could provide standardization in CONUS tidal carbon accounting until such a time as modeling and mapping advancements can quantitatively improve accuracy and precision.
潮滩湿地会产生长期的土壤有机碳 (C) 储量。因此，出于碳核算的目的，我们需要准确和精确的信息，了解这些储量的规模和空间分布。我们收集和分析了一个前所未有的土壤芯数据集，并测试了三种碳储量制图策略：将综合数据中的平均值应用于绘制的潮滩湿地，应用使用经验数据拟合的模型，以及应用土壤、植被和盐度图，以及依赖于独立生成的土壤碳图。土壤碳储量的平均值要低得多，空间和深度变化也比可用土壤图计算的储量要小。此外，碳密度的变化不能很好地根据气候、盐度、植被或土壤类型来预测。相反，该数据集表明，美国大陆（CONUS）的碳密度呈正态分布，观测结果具有可预测的范围。我们确定了最简单的策略，即应用平均碳密度（27.0kg C m），作为表现最佳的策略，并保守估计，CONUS 潮滩湿地土壤的上层 1 米含有 0.72 太字节 C。在建模和制图技术能够定量提高准确性和精确性之前，该策略可以为 CONUS 潮滩碳核算提供标准化。
