Transition to an oxygen-rich atmosphere with an extensive overshoot triggered by the Paleoproterozoic snowball Earth
Transition to an oxygen-rich atmosphere with an extensive overshoot triggered by the Paleoproterozoic snowball Earth
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DOI：
10.1016/j.epsl.2015.03.005
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发表时间：
2015-06-01
影响因子：
5.3
通讯作者：
Sekine, Yasuhito
中科院分区：
文献类型：
--
作者：
Harada, Mariko;Tajika, Eiichi;Sekine, Yasuhito
关于气候模式和大气氧气水平，地球被认为有多个稳定的、稳定的状态。古元古代是地球历史上一个值得注意的时期，因为在稳定状态之间同时发生了大规模的气候和氧化还原过渡，即雪球地球冰川和氧气的上升。地球化学证据表明，氧气的上升是一种动态的过渡，具有广泛的、长期的超调。然而，以前的模型没有解释氧气上升的动力学，使得人们对其原因机制知之甚少。在目前的研究中，我们认为氧转变和超调发生在雪球冰川终止时的气候转变的响应。生物地球化学循环模拟表明，冰川作用后长期的超级温室条件和向海洋的有效营养输入导致了高水平的初级生产力和有机碳的埋藏。这导致了冰川作用后大约10(4)年内氧气水平的突然跃升，并导致氧气水平广泛超调到目前的大气水平。这种超调持续了108年，因为大气-海洋系统的净氧气消耗效率低下。我们发现，冰期后氧水平的跃升发生在生物的短时间尺度上，这可能刺激了生态转变和/或生物创新，以实现依赖氧气的生命的繁荣。(C)2015爱思唯尔B.V.保留所有权利。
The Earth is thought to have multiple stable, steady-states regarding climate modes and atmospheric oxygen levels. The Paleoproterozoic is a remarkable period in Earth's history because of the simultaneous occurrence of large climatic and redox transitions between steady states; i.e., snowball Earth glaciation and the rise of oxygen. Geochemical evidence suggests that the oxygen rise was a dynamic transition with an extensive, long-term overshoot. However, previous models have not explained the dynamics of the oxygen rise, leaving its causal mechanism poorly understood. In the present study, we suggest that the oxygen transition with an overshoot occurred in response to a climatic transition at the termination of the snowball glaciation. Biogeochemical cycle modelling indicates that prolonged super-greenhouse conditions and effective nutrient input to the ocean after the glaciation lead to high levels of primary productivity and burial of organic carbon. This causes an abrupt jump of oxygen levels within similar to 10(4) yr after the glaciation and an extensive oxygen overshoot to the present atmospheric level. The overshoot persists for 108 yr because net consumption of oxygen in the atmosphere-ocean system is inefficient. We show that the post-glacial jump of oxygen levels occurred in biologically short timescale, which may have stimulated the ecological shift and/or biological innovations toward the prosperity of oxygen-dependent life. (C) 2015 Elsevier B.V. All rights reserved.