{"title":"海洋中氧气逐级向岸边流失：寒武纪 SPICE 事件的启示","authors":"Aske L. Sørensen, Tais W. Dahl","doi":"10.1016/j.oneear.2024.05.011","DOIUrl":null,"url":null,"abstract":"<p>Marine euxinia can amplify phosphorous-limited marine productivity by recycling phosphorous from sediments, creating a feedback loop that increases marine oxygen consumption and ultimately leads to widespread oceanic anoxia. This phenomenon is potentially more dangerous when oxygen loss arises in coastal zones. Here, we present empirical evidence and show that this cascade was set off in the Cambrian Earth system. Carbon isotopes and Mo enrichments in well-dated sediment records from the Steptoean Positive Carbon Isotope Excursion (SPICE) event reveal a rapid decline over 130 ± 30 ka to persistently low Mo levels for 1.0 ± 0.2 Ma, followed by a slower recovery. Using dynamic models for the global biogeochemical cycles, we demonstrate that marine anoxia expanded globally through a self-cascading feedback mechanism. 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引用次数: 0
摘要
海洋藻华可以通过回收沉积物中的磷来扩大磷有限的海洋生产力，从而形成一个反馈循环，增加海洋耗氧量，最终导致大范围的海洋缺氧。当沿海地区出现氧气流失时，这种现象可能会更加危险。在这里，我们提出了实证证据，并表明这种级联反应是在寒武纪地球系统中引发的。斯蒂普托恩正碳同位素激增（SPICE）事件中年代久远的沉积物记录中的碳同位素和钼富集显示，在 130 ± 30 ka 期间，钼含量迅速下降到 1.0 ± 0.2 Ma 的持续低水平，随后恢复较慢。利用全球生物地球化学循环的动态模型，我们证明了海洋缺氧是通过一种自我级联的反馈机制向全球扩展的。重要的是，我们发现底栖磷通量可能与沉积作用成比例，化学跃层向沿海地区的移动可能引发了 SPICE 事件。我们评估了当今全球尺度缺氧临界点的风险。视频摘要下载 ：下载视频 (72MB)
Cascading oxygen loss shoreward in the oceans: Insights from the Cambrian SPICE event
Marine euxinia can amplify phosphorous-limited marine productivity by recycling phosphorous from sediments, creating a feedback loop that increases marine oxygen consumption and ultimately leads to widespread oceanic anoxia. This phenomenon is potentially more dangerous when oxygen loss arises in coastal zones. Here, we present empirical evidence and show that this cascade was set off in the Cambrian Earth system. Carbon isotopes and Mo enrichments in well-dated sediment records from the Steptoean Positive Carbon Isotope Excursion (SPICE) event reveal a rapid decline over 130 ± 30 ka to persistently low Mo levels for 1.0 ± 0.2 Ma, followed by a slower recovery. Using dynamic models for the global biogeochemical cycles, we demonstrate that marine anoxia expanded globally through a self-cascading feedback mechanism. Importantly, we find that the benthic phosphorous flux likely scaled with sedimentation, and that chemocline shoaling into coastal areas likely triggered the SPICE event. We evaluate the risk of passing the tipping point for global-scale anoxia today.
One EarthEnvironmental Science-Environmental Science (all)
CiteScore
18.90
自引率
1.90%
发文量
159
期刊介绍：
One Earth, Cell Press' flagship sustainability journal, serves as a platform for high-quality research and perspectives that contribute to a deeper understanding and resolution of contemporary sustainability challenges. With monthly thematic issues, the journal aims to bridge gaps between natural, social, and applied sciences, along with the humanities. One Earth fosters the cross-pollination of ideas, inspiring transformative research to address the complexities of sustainability.
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