Spatiotemporal variations in CO2 flux in a fringing reef simulated using a novel carbonate system dynamics model
Spatiotemporal variations in CO2 flux in a fringing reef simulated using a novel carbonate system dynamics model
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使用新型碳酸盐系统动力学模型模拟岸礁中二氧化碳通量的时空变化
DOI：
10.1007/s00338-012-0964-2
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发表时间：
2013
期刊：
影响因子：
3.5
通讯作者：
Y. Tanaka and A. C. Blanco
中科院分区：
文献类型：
--
作者：
Watanabe;A.;T. Yamamoto;K. Nadaoka;Y. Maeda;T. Miyajima;Y. Tanaka and A. C. Blanco
通过将有机和无机碳通量（光合作用和钙化）、海气交换以及珊瑚和海草的底栖覆盖纳入三维水动力模型，在日本西南部石垣岛东海岸的一个边缘珊瑚礁上建立了一个碳酸盐系统动力学（CSD）模型。CSD模型可以模拟珊瑚带溶解无机碳（DIC）和总碱度的时间变化，但不能模拟海草草甸。海草草甸繁殖不良的主要原因是海底地下水排放的贡献较大，以及遥感巨型生物的分类错误。与近海区域相比，在24 h的平均观测期内，珊瑚礁具有CO2汇的作用。CSD模型还显示CO2汇/源的时空差异较大，这可能与有效的近海海水交换和小潮/大潮变化等水动力特征有关。这表明，单点观测所得的数据可能导致对总体趋势的误解，因此应仔细考虑。模型分析还表明，邻近栅格的对流通量比局部生物通量大数倍，比珊瑚带的海气通量大3个数量级。改变珊瑚或海草覆盖的敏感性试验表明，二氧化碳汇势对珊瑚覆盖的变化比海草覆盖的变化敏感得多。
A carbonate system dynamics (CSD) model was developed in a fringing reef on the east coast of Ishigaki Island, southwest Japan, by incorporating organic and inorganic carbon fluxes (photosynthesis and calcification), air–sea gas exchanges, and benthic cover of coral and seagrass into a three-dimensional hydrodynamic model. The CSD model could reproduce temporal variations in dissolved inorganic carbon (DIC) and total alkalinity in coral zones, but not in seagrass meadows. The poor reproduction in seagrass meadows can be attributed to significant contributions of submarine groundwater discharge as well as misclassification of remotely sensed megabenthos in this area. In comparison with offshore areas, the reef acted as a CO2sink during the observation period when it was averaged over 24 h. The CSD model also indicated large spatiotemporal differences in the carbon dioxide (CO2) sink/source, possibly related to hydrodynamic features such as effective offshore seawater exchange and neap/spring tidal variation. This suggests that the data obtained from a single point observation may lead to misinterpretation of the overall trend and thus should be carefully considered. The model analysis also showed that the advective flux of DIC from neighboring grids is several times greater than local biological flux of DIC and is three orders of magnitude greater than the air–sea gas flux at the coral zone. Sensitivity tests in which coral or seagrass covers were altered revealed that the CO2sink potential was much more sensitive to changes in coral cover than seagrass cover.