What did the adolescence of "livable earth" experienced?

What complicated system changes have experienced in the early development of livable earth and what impact on the marine life at that time?

The free obtained oxygen, as a necessity of most of the eukaryotic creatures, has experienced three important growth during the long -term geological history period. In terms of geology, these three changes are called "oxidation events", including the "Great Oxidation Event (GOE) of about 2.7 to 2.5 billion years ago, and about 600 million years ago about 600 million years ago "Neoproterozic Oxidation Event (NOE) and" Phanerozoic Oxidation Event (POE "about 400 million years ago. From the perspective of changes, Goe achieves atmospheric oxygen content from <0.01% PAL to 0.1% PAL (PAL, PRESENT ATMOSPHERIC Level refers to the modern atmospheric level). NOE witnessed the increase of the atmospheric oxygen content of 1% pal to 10% pal, and POE mainly refers to the atmospheric oxygen content that really achieves and maintained at a modern level.

The atmospheric oxidation incident at each stage is accompanied by the important changes of the earth's ecosystem -GOE and early single -cell bacteria (such as cyanobacteria) are related to the appearance of NOE and early animals and the outbreak. The expansion of the ecosystem. In the early ancient times (540 million to 420 million years), as an important transition period, not only witnessed the periodic rise in the atmospheric oxygen content between NOE and POE and the continuous decline of carbon dioxide content, but also recorded the comprehensive establishment of the marine ecosystem. The complexity and the rise of land plant systems and other earth system changes (Figure 1), so it can be called "livable earth".

Figure 1 During the early ancient generation and the changes in the earth system (refer to ZHANG et al., 2021)

The early ancient generations have since "the Great Blast of the Cambrian", and the rapid development and prosperity of marine animals have added a lot of vitality to this azure star ball. However, there must be a crisis with development. The Cambrian, the content of the atmospheric carbon dioxide is estimated to exceed 20 pal, which leads to a long greenhouse climate in the earth. The ocean under this climatic conditions is much lower than the modern ocean, and the water body layering is serious. At the same time, under the humid and humid climate, the intensification of land weathering has led to a large amount of land source nutritional salt into the ocean, and the surface seawater has a wide range of rich nutritionalization. The organic matter of the seawater surface layer is consumed in the process of oxidation and decomposition, which consumes a lot of oxygen, which causes the oxygen hypoxic phenomenon frequently. Therefore, this has also become the cause of biological diversity in the middle-late Han Wu Shi.

Entering the Okota, the weathered of the base rock after the landmaking and volcanic eruption caused the carbon dioxide to be consumed for a long time. It is the main reason for the major radiation of Okota. At the same time, due to the early low plant landing and the exacerbation of land weathering, the further enrichment of nutritional salt caused a large amount of organic carbon in the ocean to be buried, which led to further decline in the concentration of the atmospheric carbon dioxide. The ice period is widely recorded.

Under the double influence of the ice room climate and oxygen hypoxia, the ocean ushered in the first major ecological crisis, causing the cluster of marine life. Frequent volcanic activities continue to spray carbon dioxide, eventually suspend the ice period, and cause a short greenhouse climate in early Zhi Li Ji. Accompanied by the hypoxia phenomenon of marine ecosystems, the recovery of the marine ecosystem is limited. With the further expansion of the landing plant (especially plants developed by the root system), the content of atmospheric oxygen gradually risen to modern levels, and the content of atmospheric carbon dioxide decreased for a long time. During the period of Zhili-Mud Pot, multiple periods of climate became cold. Synchronization is that the ocean and land are gradually giving birth to vitality.

Therefore, as a "livable earth" adolescent period, the early ancient generation became an important period of collaborative evolution of biological and environmental evolution in geological history. It also provided valuable reference and reference for us to "protect the environment and live in harmony between man and nature". After all, in this series of earth system changes, the atmosphere-land-marine system always revolves around the keyword of "carbon cycle". Based on history, we can see the prosperity of nature. Today, when the country vigorously promotes the "dual carbon" strategy, we need to explore the past and "carbon" of the "livable earth" more deeply.

Related original text

Zhang Junpeng, Li Chao, Zhang Yuanyong. The geological records and background mechanisms of the early ancient generation of oxygen incident. Science report, 2022, 67 (15): 1644-1659, https://doi.org/10.1360/tb-2021- 0535

Zhang JP, Edwards CT, Diamond CW, Lyons TW, Zhang YD. Marine oxygenation, deoxygenation, and life during the Early Paleozoic: An overview. Palaeogeogr Palaeoclimatol Palaeoecol, 2021, 584: 110715.

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