Late inception of a resiliently oxygenated upper ocean
Late inception of a resiliently oxygenated upper ocean
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DOI：
10.1126/science.aar5372
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发表时间：
2018-07-13
期刊：
影响因子：
56.9
通讯作者：
Lu, Zunli
中科院分区：
文献类型：
--
作者：
Lu, Wanyi;Ridgwell, Andy;Lu, Zunli
随着时间的推移，海洋和大气中氧气含量的上升对增强地球表面环境的可居住性至关重要。很少有氧化还原替代物可以追踪上层海洋中继生动物生存阈值附近溶解氧浓度的长期变化。我们提出了一个广泛的汇编碘钙比（I/Ca）在海洋碳酸盐。我们的记录支持了大约4亿年前大气中氧分压的大幅上升，并揭示了大约200年前上层海洋的氧合作用在相对可持续的近现代条件下的阶跃变化。一个地球系统模型表明，有机物再矿化向更深的深度转移，这可能是由于真核浮游生物的体积和生物矿化的增加，可能驱动了类似于200 Ma以前的I/Ca信号。
Rising oceanic and atmospheric oxygen levels through time have been crucial to enhanced habitability of surface Earth environments. Few redox proxies can track secular variations in dissolved oxygen concentrations around threshold levels for metazoan survival in the upper ocean. We present an extensive compilation of iodine-to-calcium ratios (I/Ca) in marine carbonates. Our record supports a major rise in the partial pressure of oxygen in the atmosphere at similar to 400 million years (Ma) ago and reveals a step change in the oxygenation of the upper ocean to relatively sustainable near-modern conditions at similar to 200 Ma ago. An Earth system model demonstrates that a shift in organic matter remineralization to greater depths, which may have been due to increasing size and biomineralization of eukaryotic plankton, likely drove the I/Ca signals at similar to 200 Ma ago.