Is Submarine Groundwater Discharge (SGD) Important for the Historical Fish Kills and Harmful Algal Bloom Events of Mobile Bay?
Is Submarine Groundwater Discharge (SGD) Important for the Historical Fish Kills and Harmful Algal Bloom Events of Mobile Bay?
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DOI：
10.1007/s12237-018-0485-5
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发表时间：
2018-11
影响因子：
2.7
通讯作者：
D. Montiel;Alexander F. Lamore;Jackson Stewart;N. Dimova
中科院分区：
文献类型：
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作者：
D. Montiel;Alexander F. Lamore;Jackson Stewart;N. Dimova
一个多世纪以来，大规模的鱼类和甲壳类动物死亡（当地称为jubilees）和有害藻华（HABs）一直发生在阿拉巴马州的莫比尔湾（Mobile Bay）。事实上，关于1867年莫比尔湾发生的“禧年”事件的第一个记录，是有史以来第一个有记载的海洋动物因缺氧而大量死亡的案例。为了评估海底地下水排放（SGD）在莫比尔湾朱比利和赤潮发生中的重要性，采用多方法进行了为期3年的研究。利用地球化学和浅层地球物理相结合的方法，揭示了渤海湾SGD的显著时空变化。受jubilee影响的海湾水域季节性缺氧的发展是缺氧SGD输入的结果，其大小和空间分布受海湾现代开发过程中形成的浅层岩性非均质性控制。尽管与河流流量相比，莫比尔湾总淡水输入的SGD贡献在0.2%（雨季）至5%（旱季）之间，但海湾总SGD的80%发生在受缺氧和jubilees生态影响的地区。在这些地区，SGD占旱季总水量的37%，与一年中发生银潮和赤潮的时间一致。总之，虽然SGD可能不是莫比尔湾或全球其他河口的重要淡水来源，但由特定地点的岩性非均质性引起的SGD增强可能在近岸水域缺氧和生态问题的发展中发挥关键作用。
Large-scale fish and crustacean kills, locally known asJubilees, and harmful algal blooms (HABs) have been occurring in Mobile Bay (Alabama) for more than a century. In fact, the first record describing aJubileeevent in Mobile Bay during 1867 was the first ever-documented case of mass mortalities of marine animals caused by hypoxia. To evaluate the importance of submarine groundwater discharge (SGD) in the occurrence ofJubileesand HABs in Mobile Bay, a 3-year study was conducted using a multi-method approach. Significant spatial and temporal variations of SGD were revealed in the bay only by applying a combination of geochemical and shallow geophysical techniques. The development of seasonal hypoxia observed in bay waters in areas impacted byJubileeswas the result of anoxic SGD inputs, which magnitude and spatial distribution were controlled by shallow lithological heterogeneities created during the modern development of the bay. Although when compared to the river discharge SGD contributed between 0.2 (wet season) and 5% (dry season) of the total freshwater inputs to Mobile Bay, 80% of the total SGD in the bay occurred in areas ecologically impacted by hypoxia andJubilees. In these areas, SGD comprised up to 37% of the total water inputs during the dry season, coinciding with the time of the year whenJubileesand HABs occur. In conclusion, while SGD might not be a significant source of fresh water to Mobile Bay or other estuaries worldwide, enhanced SGD caused by site-specific lithological heterogeneities can have a critical role in the development of hypoxia and ecological issues in nearshore waters.