Institute for the Environment, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina , USA.
Department of Biology, The University of North Carolina at Chapel Hill , Chapel Hill, North Carolina , USA.
PeerJ. 2014 May 22;2:e388. doi: 10.7717/peerj.388. eCollection 2014.
Mangroves can capture and store organic carbon and their protection and therefore their restoration is a component of climate change mitigation. However, there are few empirical measurements of long-term carbon storage in mangroves or of how storage varies across environmental gradients. The context dependency of this process combined with geographically limited field sampling has made it difficult to generalize regional and global rates of mangrove carbon sequestration. This has in turn hampered the inclusion of sequestration by mangroves in carbon cycle models and in carbon offset markets. The purpose of this study was to estimate the relative carbon capture and storage potential in natural and restored mangrove forests. We measured depth profiles of soil organic carbon content in 72 cores collected from six sites (three natural, two restored, and one afforested) surrounding Muisne, Ecuador. Samples up to 1 m deep were analyzed for organic matter content using loss-on-ignition and values were converted to organic carbon content using an accepted ratio of 1.72 (g/g). Results suggest that average soil carbon storage is 0.055 ± 0.002 g cm(-3) (11.3 ± 0.8% carbon content by dry mass, mean ± 1 SE) up to 1 m deep in natural sites, and 0.058 ± 0.002 g cm(-3) (8.0 ± 0.3%) in restored sites. These estimates are concordant with published global averages. Evidence of equivalent carbon stocks in restored and afforested mangrove patches emphasizes the carbon sink potential for reestablished mangrove systems. We found no relationship between sediment carbon storage and aboveground biomass, forest structure, or within-patch location. Our results demonstrate the long-term carbon storage potential of natural mangroves, high effectiveness of mangrove restoration and afforestation, a lack of predictability in carbon storage strictly based on aboveground parameters, and the need to establish standardized protocol for quantifying mangrove sediment carbon stocks.
红树林可以捕获和储存有机碳，保护红树林因此也是减缓气候变化的一个组成部分。然而，关于红树林长期碳储存的实证测量以及存储如何随环境梯度而变化的信息却很少。这个过程的背景依赖性，加上地理上有限的实地采样，使得很难概括红树林的区域和全球碳封存率。这反过来又阻碍了将红树林的固碳纳入碳循环模型和碳抵消市场。本研究的目的是估算自然和修复的红树林的相对碳捕获和储存潜力。我们对厄瓜多尔穆伊斯内周围六个地点（三个自然、两个修复和一个造林）的 72 个样本芯的土壤有机碳含量进行了深度剖面测量。使用燃烧损失法对深度达 1 米的样本进行有机质含量分析，并使用公认的 1.72（g/g）比率将值转换为有机碳含量。结果表明，自然地点的土壤碳储存平均为 0.055 ± 0.002 g cm(-3)（干质量的 11.3 ± 0.8%，平均值 ± 1 个标准差），深度可达 1 米，而修复地点的土壤碳储存平均为 0.058 ± 0.002 g cm(-3)（干质量的 8.0 ± 0.3%）。这些估计与已发表的全球平均值一致。在修复和造林的红树林斑块中发现的碳储量相等的证据强调了重新建立的红树林系统的碳汇潜力。我们没有发现沉积物碳储存与地上生物量、森林结构或斑块内位置之间的关系。我们的研究结果表明了自然红树林的长期碳储存潜力、红树林恢复和造林的高效性、根据地上参数严格预测碳储存的缺乏，以及需要建立标准化协议来量化红树林沉积物碳储量。
