Breathless through Time: Oxygen and Animals across Earth’s History
Breathless through Time: Oxygen and Animals across Earth’s History
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DOI：
10.1086/721754
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发表时间：
2022-09
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影响因子：
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通讯作者：
E. Sperling;Thomas H. Boag;Murray I. Duncan;Cecilia R. Endriga;J. Marquez;D. B. Mills;P. Monarrez
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文献类型：
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作者：
E. Sperling;Thomas H. Boag;Murray I. Duncan;Cecilia R. Endriga;J. Marquez;D. B. Mills;P. Monarrez
在地球历史上，大气和海洋中的氧气水平发生了巨大变化，对海洋生物产生了重大影响。由于地球历史的早期缺乏大气中的氧气和动物，因此一种持续的共同进化叙事将氧气变化与动物多样性的变化联系起来。虽然人们长期以来认为，氧气在寒武纪时期上升到基本上现代的水平，但现在认为可能会有更温和的增长。因此，如果氧气的增加促进了寒武纪的大爆发，那么它是通过在低O2下跨越临界生态阈值来实现的。在古生代早期，大气中的氧气可能保持在低或中等水平，这可能导致后生动物的灭绝率很高，直到氧气最终在古生代后期上升到现代水平。在这一点之后，海洋脱氧（和海洋大规模喷发）越来越多地与大火成岩省喷发有关-大量火山碳输入到地球系统，导致全球变暖，海洋酸化和氧气流失。虽然这些古代事件的时间尺度限制了它们作为现代人类全球变化的精确模拟的实用性，但地质记录的明确信息是，大量快速的二氧化碳注入地球系统始终会导致今天观察到的相同的致命三重压力。理解氧气变化（或者更广泛地说，温度依赖性缺氧）在深时间的影响的下一个前沿需要从生态生理学的方法，这将有助于保护生物学家更好地校准生物圈在大的分类，空间和时间尺度的反应。
Oxygen levels in the atmosphere and ocean have changed dramatically over Earth history, with major impacts on marine life. Because the early part of Earth’s history lacked both atmospheric oxygen and animals, a persistent co-evolutionary narrative has developed linking oxygen change with changes in animal diversity. Although it was long believed that oxygen rose to essentially modern levels around the Cambrian period, a more muted increase is now believed likely. Thus, if oxygen increase facilitated the Cambrian explosion, it did so by crossing critical ecological thresholds at low O2. Atmospheric oxygen likely remained at low or moderate levels through the early Paleozoic era, and this likely contributed to high metazoan extinction rates until oxygen finally rose to modern levels in the later Paleozoic. After this point, ocean deoxygenation (and marine mass extinctions) is increasingly linked to large igneous province eruptions—massive volcanic carbon inputs to the Earth system that caused global warming, ocean acidification, and oxygen loss. Although the timescales of these ancient events limit their utility as exact analogs for modern anthropogenic global change, the clear message from the geologic record is that large and rapid CO2 injections into the Earth system consistently cause the same deadly trio of stressors that are observed today. The next frontier in understanding the impact of oxygen changes (or, more broadly, temperature-dependent hypoxia) in deep time requires approaches from ecophysiology that will help conservation biologists better calibrate the response of the biosphere at large taxonomic, spatial, and temporal scales.