A largely invariant marine dissolved organic carbon reservoir across Earth's history
A largely invariant marine dissolved organic carbon reservoir across Earth's history
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DOI：
10.1073/pnas.2103511118
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发表时间：
2021-10-05
影响因子：
11.1
通讯作者：
Reinhard, Christopher T.
中科院分区：
文献类型：
--
作者：
Fakhraee, Mojtaba;Tarhan, Lidya G.;Reinhard, Christopher T.
海洋溶解有机碳（DOC）是海洋中最大的还原碳库，在全球碳循环中起着重要作用，并对大气中氧和二氧化碳的丰度起着调节作用。尽管它在全球海洋地球化学循环中的重要性，海洋DOC水库的长期历史是不好的限制。尽管如此，在地球历史上，海洋DOC水库的规模发生了重大变化，通常被用来解释海洋化学，碳循环和海洋生态的变化。在这里，我们提出了一个修订后的观点，海洋DOC浓度的演变，使用一个机械的碳循环模型，可以重现DOC浓度在好氧和缺氧的现代环境。我们使用这个模型来证明，海洋DOC水库的整体规模可能经历了非常小的变化，通过地球的历史，尽管海洋-大气系统的氧化还原状态和生物碳泵的性质和效率的重大变化。一个相对静态的海洋DOC水库在整个地球的历史，使它不太可能在海洋DOC浓度的重大变化一直负责驱动大规模的表面碳重新分配或大的碳同位素漂移观察到地球的地层记录，并质疑以前假设的海洋DOC水平和早期动物的出现和辐射之间的联系。
Marine dissolved organic carbon (DOC), the largest pool of reduced carbon in the oceans, plays an important role in the global carbon cycle and contributes to the regulation of atmospheric oxygen and carbon dioxide abundances. Despite its importance in global biogeochemical cycles, the long-term history of the marine DOC reservoir is poorly constrained. Nonetheless, significant changes to the size of the oceanic DOC reservoir through Earth's history have been commonly invoked to explain changes to ocean chemistry, carbon cycling, and marine ecology. Here, we present a revised view of the evolution of marine DOC concentrations using a mechanistic carbon cycle model that can reproduce DOC concentrations in both oxic and anoxic modern environments. We use this model to demonstrate that the overall size of the marine DOC reservoir has likely undergone very little variation through Earth's history, despite major changes in the redox state of the ocean-atmosphere system and the nature and efficiency of the biological carbon pump. A relatively static marine DOC reservoir across Earth's history renders it unlikely that major changes in marine DOC concentrations have been responsible for driving massive repartitioning of surface carbon or the large carbon isotope excursions observed in Earth's stratigraphic record and casts doubt on previously hypothesized links between marine DOC levels and the emergence and radiation of early animals.