Submarine Groundwater Discharge in the Northern Bohai Sea, China: Implications for Coastal Carbon Budgets and Buffering Capacity
Submarine Groundwater Discharge in the Northern Bohai Sea, China: Implications for Coastal Carbon Budgets and Buffering Capacity
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DOI：
10.1029/2022jg006810
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发表时间：
2022-07
期刊：
影响因子：
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通讯作者：
Yan Zhang;Changpei Zou;Zhaohui Aleck Wang;Xuejing Wang;Zhenzhong Zeng;Kai Xiao;Huaming Guo;Xiaowei Jiang;Zhenyang Li;Hailong Li
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文献类型：
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作者：
Yan Zhang;Changpei Zou;Zhaohui Aleck Wang;Xuejing Wang;Zhenzhong Zeng;Kai Xiao;Huaming Guo;Xiaowei Jiang;Zhenyang Li;Hailong Li
海底地下水排放（SGD）已被广泛认为是沿海水域溶解营养物的重要来源，并影响营养物生物地球化学。相比之下，关于新元对沿海碳预算影响的信息很少。在这里，我们评估了辽东湾（中国渤海最大的海湾）的 SGD 和相关碳（溶解无机碳 [DIC] 和总碱度 [TA]）通量，并讨论了它们对沿海 DIC 预算和缓冲能力的边界影响。根据 223Ra 和 228Ra 质量平衡模型，SGD 通量估计为 (0.92–1.43) × 109 m3 d−1。 SGD 是 DIC 的最大来源，占 DIC 总来源的 55%–77%。 SGD 衍生的 TA 与 DIC 通量之比较低（<1）以及镭同位素与海水 pH 值之间的负相关性表明 SGD 可能会降低辽东湾海水 pH 值。结合辽东湾地下水碳数据和文献数据，我们发现中国海域SGD衍生的DIC通量是河流的4-9倍。通过分析中国沿海地下水中的TA/DIC比值和相关碳通量，认为SGD部分降低了接收海水中的CO2缓冲能力。这些在海湾尺度和国家尺度上获得的结果表明，SGD 是碳预算的重要组成部分，可能在调节沿海缓冲能力和大气二氧化碳封存方面发挥关键作用。
Submarine groundwater discharge (SGD) has been widely recognized as an important source of dissolved nutrients in coastal waters and affects nutrient biogeochemistry. In contrast, little information is available on SGD impacts on coastal carbon budgets. Here, we assessed the SGD and associated carbon (dissolved inorganic carbon [DIC] and total alkalinity [TA]) fluxes in Liaodong Bay (the largest bay of the Bohai Sea, China) and discussed their border implications for coastal DIC budget and buffering capacity. Based on 223Ra and 228Ra mass balance models, the SGD flux was estimated to be (0.92–1.43) × 109 m3 d−1. SGD was the largest contributor of DIC, accounting for 55%–77% of the total DIC sources. The low ratio (<1) of SGD‐derived TA to DIC fluxes and negative correlation between radium isotopes and pH in seawater implied that SGD would potentially reduce seawater pH in Liaodong Bay. Combining the groundwater carbon data in Liaodong Bay with literature data, we found that the SGD‐derived DIC flux off China was 4–9 times greater than those from rivers. By analyzing the TA/DIC ratios in groundwater along the Chinese coast and related carbon fluxes, SGD was thought to partially reduce the CO2 buffer capacity in receiving seawater. These results obtained at the bay scale and national scale suggest that SGD is a significant component of carbon budget and may play a critical role in modulating coastal buffering capacity and atmospheric CO2 sequestration.