Mangroves have the capacity to sequester organic carbon (C_org) in their sediments permanently. However, the carbon budget of mangroves is also affected by the total alkalinity (TA) budget. Principally, TA emitted from carbonate sediment dissolution is a perennial sink of atmospheric CO₂. The assessment of the TA budget of mangrove carbonate sediments in the Red Sea revealed a large TA emission of 403 ± 17 mmol m⁻² d⁻¹, independent of light, seasons, or the presence of pneumatophores, compared to −36 ± 10 mmol m⁻² d⁻¹ in lagoon sediment. We estimate the TA emission from carbonate dissolution in Red Sea mangroves supported a CO₂ uptake of 345 ± 15 gC m⁻² yr⁻¹, 23‐fold the C_org burial rate of 15 gC m⁻² yr⁻¹. The focus on C_org burial in sediments may substantially underestimate the role of mangroves in CO₂ removal. Quantifying the role of mangroves in climate change mitigation requires carbonate dissolution to be included in assessments.

中文翻译：

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红树林生态系统中的总碱度生产揭示了被忽略的蓝碳成分

红树林具有永久性隔离其沉积物中有机碳（C _org）的能力。但是，红树林的碳预算也受到总碱度（TA）预算的影响。原则上，碳酸盐沉积物溶解释放出的TA是大气中CO ₂的多年生汇。对红海中红树林碳酸盐沉积物的TA预算的评估表明，与-36±10 mmol相比，无论光照，季节或有无肺炎的存在，TA的发射量均为403±17 mmol m ^-2 d ^-1，而与光和季节无关。 m ^-2 d ^-1在泻湖沉积物中。我们估计红海红树林碳酸盐溶解所产生的TA排放量支持345±15 gC m的CO ₂吸收⁻² yr ^-1，_Corg埋葬率15 gC m ⁻² yr ^-1的23倍。对沉积物中_Corg埋葬的关注可能大大低估了红树林在CO ₂去除中的作用。量化红树林在缓解气候变化中的作用需要将碳酸盐的溶解纳入评估。