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首页> 外文期刊>Estuarine Coastal and Shelf Science >Over 100 years of environmental change recorded by foraminifers and sediments in Mobile Bay, Alabama, Gulf of Mexico, USA
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Over 100 years of environmental change recorded by foraminifers and sediments in Mobile Bay, Alabama, Gulf of Mexico, USA

机译：美国墨西哥湾阿拉巴马州莫比尔湾的有孔虫和沉积物记录了超过100年的环境变化

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摘要

The marine microfauna of Mobile Bay has been profoundly influenced by the development and expansion of the primary shipping channel over the last ～100 years. Foraminifers and sediments from seven box cores with excess lead-210 chronology document that channel dredging and spoil disposal have altered circulation, reduced estuarine mixing, changed sedimentation patterns, and caused a faunal turnover within the bay. Beginning in the late 1800s, changes in estuarine mixing allowed for greater low-pH freshwater influence in the bay, and ultimately began environmental changes that resulted in the loss of calcareous foraminifers. By the early 1900s, box cores throughout Mobile Bay record a ~ 100-year trend of increasing calcareous test dissolution that continues to the present. Since the completion of the current shipping channel in the 1950s, restricted tidal flushing and increased terrestrial organic matter, documented by carbon-to-nitrogen ratios, stimulated an increase in agglutinated foraminiferal densities. However, in deeper areas of the bay, hypoxic water has negatively impacted the marine microfauna. Comparisons of the present-day foraminiferal assemblage with foraminifers collected in the early 1970s indicate that the continued biologic loss of calcareous foraminifers in the bay has allowed the introduction of a new agglutinated foraminiferal species into the bay.
机译：过去100年来，莫比尔湾的海洋动物区系受到主要航运渠道的发展和扩展的深刻影响。来自七个盒芯的有孔虫和沉积物以及过量的210年代铅记录表明，河道疏and和弃渣处理改变了环流，减少了河口混合，改变了沉积方式，并引起了海湾内的动物群更新。从1800年代后期开始，河口混合的变化使海湾中的低pH淡水受到更大的影响，最终开始了环境变化，导致钙质有孔虫的损失。到1900年代初，整个莫比尔湾的盒形核记录了大约100年钙质测试溶出度增加的趋势，这种趋势一直持续到现在。自从1950年代完成当前的运输渠道以来，潮汐潮汐受到限制，陆地有机物的增加（碳碳比证明了这一点）刺激了有孔虫密度的增加。但是，在海湾的较深区域，低氧水对海洋微动物群产生了负面影响。目前的有孔虫组合与1970年代初期收集的有孔虫的比较表明，海湾中钙质有孔虫的持续生物损失已允许将一种新的有凝集性有孔虫种引入该海湾。

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