Mangrove forests have gained recognition for their potential role in climate change mitigation due to carbon sequestration in live trees, and carbon storage in the sediments trapped by mangrove tree roots and pneumatophores. Africa hosts about 19% of the world’s mangroves, yet relatively few studies have examined the carbon stocks of African mangroves. The available studies report considerable differences among sites and amongst the different pools of carbon stocks. None considered the effects of seaward distance. We present details of AGC and SOC carbon stocks for Lindi in Tanzania, and focus on how these values differ with increasing seaward distance and, how our results compare to those reported elsewhere across Africa. AGC ranged between 11 and 55 Mg C ha−1, but was not significantly affected by seaward distance. SOC for 0–1 m depth ranged from 154 to 484, with a mean of 302 Mg C ha−1. SOC was significantly negatively correlated with seaward distance. Mangrove type (estuarine/oceanic), soil erosion, soil depth may explain these differences We note important methodological differences in previous studies on carbon stocks in mangroves in Africa. This study indicates that seaward distance has an important effect on SOC stocks in the Lindi region of Tanzania. SOC should be fully incorporated into national climate change mitigation policies. Studies should report seaward distance and to describe the type of mangrove stand to make results easily comparable across sites and to assess the true value of Blue Carbon in Africa. We recommend focusing on trees > 10 cm diameter for AGC, and sampling soils to at least 1 m depth for SOC, which would provide a more complete assessment of the potentially considerable mangrove carbon store.

中文翻译：

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海口距离对河口红树林生态系统地上和地下碳储量的影响

由于活树中的碳固存以及红树林的树根和气穴所捕获的沉积物中的碳储存，红树林在减缓气候变化方面的潜在作用已获得认可。非洲拥有全球约19％的红树林，但很少有研究检查非洲红树林的碳储量。现有的研究报告了站点之间以及不同碳库之间的巨大差异。没有人考虑过海距离的影响。我们提供了坦桑尼亚Lindi的AGC和SOC碳储量的详细信息，并着重于这些值随海距离增加的差异以及我们的结果与非洲其他地区报告的结果之间的比较。AGC的范围在11至55 Mg C ha-1之间，但不受海向距离的影响很大。0-1 m深度的SOC从154到484，平均302 Mg C ha-1。SOC与海向距离呈显着负相关。红树林类型（河口/海洋），水土流失，土壤深度可能解释了这些差异。我们注意到先前在非洲红树林碳储量研究中存在重要的方法学差异。这项研究表明，向海距离对坦桑尼亚Lindi地区的SOC储量有重要影响。SOC应该完全纳入国家减缓气候变化政策。研究应报告沿海距离，并描述红树林的类型，以使结果易于在各个地点之间进行比较，并评估非洲蓝碳的真实价值。我们建议针对AGC直径大于10厘米的树木，并针对SOC采样至少1 m深度的土壤，