Export of inorganic carbon from two Southeast Asian mangrove forests to adjacent estuaries as estimated by the stable isotope composition of dissolved inorganic carbon
Export of inorganic carbon from two Southeast Asian mangrove forests to adjacent estuaries as estimated by the stable isotope composition of dissolved inorganic carbon
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DOI：
10.1029/2008jg000861
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发表时间：
2009-03
期刊：
影响因子：
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通讯作者：
T. Miyajima;Y. Tsuboi;Yoshiyuki Tanaka;I. Koike
中科院分区：
文献类型：
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作者：
T. Miyajima;Y. Tsuboi;Yoshiyuki Tanaka;I. Koike
利用新开发的同位素（δ 13 C）质量平衡模型定量估算了热带河口红树林对溶解无机碳（DIC）动态的影响。为此目的，DIC的浓度和δ 13 C测定跨盐度梯度的两个河口面向安达曼海。DIC的纵向分布可以解释为在低流量期间（2006年3月）河水和海水DIC的保守混合，而在高流量期间（2006年12月）观察到DIC的净积累高达190 μmol L−1。δ13CDIC值通常低于河水和海水DIC混合的预期值，这是由于来自滨江红树林的13C耗尽DIC输入。通过所提出的模型估计，河口沃茨中源自红树林的DIC浓度高达856 μmol L−1，并且在低流量期间更高。这表明，红树林出口到河口的DIC水平远远高于DIC的净积累。我们的研究结果证实，红树林的功能作为一个有效的二氧化碳泵，从大气中的二氧化碳，并将其释放到河口沃茨。研究表明，δ13CDIC是红树林等滨海湿地DIC入海排放的一个敏感的定量指标。
The influence of mangrove forests on the dynamics of dissolved inorganic carbon (DIC) in tropical estuaries was estimated quantitatively using newly developed isotope (δ13C) mass balance models that take into account both the input of DIC and the air‐water exchange of CO2. To this aim, the concentration and δ13C of DIC were determined across the salinity gradient of two river estuaries facing the Andaman Sea. The longitudinal distribution of DIC could be explained by conservative mixing of the river water and seawater DIC in the low‐discharge period (March 2006), while a net accumulation of DIC up to 190 μmol L−1 was observed in the high‐discharge period (December 2006). δ13CDIC values were generally lower than expected for the mixing of the river water and seawater DIC, due to the 13C‐depleted DIC inputs from the riverside mangroves. The concentration of mangrove‐derived DIC in the estuarine waters was estimated by the proposed models to be as much as 856 μmol L−1, and was higher during the low‐discharge period. This suggested that the mangroves exported much higher levels of DIC to the estuaries than indicated by the net accumulation of DIC. Our results confirm that mangroves function as an effective CO2 pump that takes CO2 from the atmosphere and releases it into estuarine waters. This study illustrates that δ13CDIC is a sensitive and quantitative indicator for DIC emission to the sea from coastal wetlands including mangroves.