Assessment of Carbon Sequestration Potential in Coastal Wetlands
Assessment of Carbon Sequestration Potential in Coastal Wetlands
复制标题
DOI：
10.1007/978-94-007-4159-1_24
复制
发表时间：
2012
影响因子：
2.7
通讯作者：
J. Morris;J. Edwards;S. Crooks;E. Reyes
中科院分区：
文献类型：
--
作者：
J. Morris;J. Edwards;S. Crooks;E. Reyes
本文描述了模型（沼泽平衡模型）对当代沿海湿地单位面积固碳潜力的模拟，预测海平面在下个世纪上升1米之前和之后。单位速率通常在0.2至0.3 Mg C / ha - 1年- 1之间，主要取决于海平面上升速率、潮汐振幅和悬浮沉积物（TSS）的浓度。海平面上升将对现有湿地的固碳产生显著影响，存在最大限度固碳的最佳潮差和TSS。总体而言，中潮河口的碳固存和库存量最大。潮汐振幅<50厘米和TSS < 20 mg l - 1的沼泽在下个世纪海平面上升1米时不太可能存活下来。美国大部分海岸线以潮汐振幅小于1米为主。如果现有的小于1 m的湿地表面不能保持相对于平均海平面的高程，那么海平面每上升1 m，滨海湿地的面积范围就会减少，即海侵扩张将受到地形的限制。另一方面，如果现有的植被表面存活下来，在没有人为迁移障碍的情况下，沿海湿地面积可以扩大71%。根据模型得出的美国邻近地区的当代碳固存率估计为0.44 Tg C - 1年，处于早期核算的低端。海平面每上升1米，在现有湿地表面100%存活的情况下，碳固存率在TSS = 20和80 mg l - 1时分别上升至0.58和0.73 Tg C - 1年，比当代高32-66%。在全球范围内，沿海湿地的碳固存可能不到每年化石燃料排放量的0.2%。因此，沿海湿地吸收了全球碳通量的一小部分，尽管它们在长时间尺度上具有更大的意义。湿地土壤碳储量大。由于沿海湿地转变为其他土地用途，造成了大量的湿地损失，这为恢复湿地创造了机会，对当地具有重要意义。
This paper describes model (Marsh Equilibrium Model) simulations of the unit area carbon sequestration potential of contemporary coastal wetlands before and following a projected 1 m rise in sea level over the next century. Unit rates ranged typically from 0.2 to 0.3 Mg C ha−1year−1depending primarily on the rate of sea-level rise, tidal amplitude, and the concentration of suspended sediment (TSS). Rising sea level will have a significant effect on the carbon sequestration of existing wetlands, and there is an optimum tide range and TSS that maximize sequestration. In general, the results show that carbon sequestration and inventories are greatest in mesotidal estuaries. Marshes with tidal amplitudes <50 cm and TSS < 20 mg l−1are unlikely to survive a 1 m rise in sea level during the next century. The majority of the United States coastline is dominated by tidal amplitude less than 1 m. The areal extent of coastal wetlands will decrease following a 1 m rise in sea level if existing wetland surfaces <1 m fail to maintain elevation relative to mean sea level, i.e. expansion by transgression will be limited by topography. On the other hand, if the existing vegetated surfaces survive, coastal wetland area could expand by 71%, provided there are no anthropogenic barriers to migration. The model-derived contemporary rate of carbon sequestration for the conterminous United States was estimated to be 0.44 Tg C year−1, which is at the low end of earlier accounts. Following a 1 m rise in sea level, with 100% survival of existing wetland surfaces, rates of carbon sequestration rise to 0.58 and 0.73 Tg C year−1at TSS = 20 and 80 mg l−1, respectively, or 32–66% higher than the contemporary rate. Globally, carbon sequestration by coastal wetlands accounts for probably less than 0.2% of the annual fossil fuel emission. Thus, coastal wetlands sequester a small fraction of global carbon fluxes, though they take on more significance over long time scales. The deposits of carbon in wetland soils are large. There have been large losses of coastal wetlands due to their conversion to other land uses, which creates opportunities for restoration that are locally significant.