The beginning of the Phanerozoic saw two biological events that set the stage for all life that was to come: ( a) the Cambrian Explosion (the appearance of most marine invertebrate phyla) and ( b) the Great Ordovician Biodiversification Event (GOBE), the subsequent substantial accumulation of marine biodiversity. Here, we examine the current state of understanding of marine environments and ecosystems from the late Ediacaran through the Early Ordovician, which spans this biologically important interval. Through a compilation and review of the existing geochemical, mineralogical, sedimentological, and fossil records, we argue that this interval was one of sustained low and variable marine oxygen levels that both led to animal extinction and fostered biodiversification events throughout the Cambrian and Early Ordovician. Therefore, marine ecosystems of this interval existed on the edge—with enough oxygen to sustain them but with the perennial risk of environmental stressors that could overwhelm them.▪ We review the current research on geochemistry and paleontology of the Cambrian and Early Ordovician periods. ▪ Low and oscillating oxygen levels in the marine realm promoted diversification and evolutionary innovation but also drove several extinction events. ▪ Taphonomic modes and marine authigenic pathways that were abundant in the Cambrian were supported by oceans that were persistently less oxygenated than today's oceans.Expected final online publication date for the Annual Review of Earth and Planetary Sciences, Volume 52 is May 2024. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

中文翻译：

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边缘生命：寒武纪海洋领域和氧化


显生宙之初发生了两个生物事件，为所有生命的到来奠定了基础：（a）寒武纪生物大爆发（大多数海洋无脊椎动物门的出现）和（b）奥陶纪大生物多样性事件（GOBE），随后海洋生物多样性大量积累。在这里，我们研究了对从埃迪卡拉晚期到奥陶纪早期的海洋环境和生态系统的了解现状，该时期跨越了这个生物学上重要的时期。通过对现有地球化学、矿物学、沉积学和化石记录的汇编和回顾，我们认为这一时期是海洋含氧量持续低且变化的时期之一，它既导致了动物灭绝，又促进了整个寒武纪和早奥陶世的生物多样性事件。因此，这一时期的海洋生态系统存在于边缘——有足够的氧气来维持它们，但常年面临着可能压垮它们的环境压力因素的风险。▪ 我们回顾了当前关于寒武纪和早奥陶世时期地球化学和古生物学的研究。 ▪ 海洋领域的低氧水平和振荡促进了多样化和进化创新，但也引发了几次灭绝事件。 ▪ 寒武纪丰富的埋藏模式和海洋自生路径得到了比当今海洋含氧量持续较低的海洋的支持。《地球与行星科学年度评论》第 52 卷的预计最终在线出版日期为 2024 年 5 月。请参阅 http ://www.annualreviews.org/page/journal/pubdates 了解修订后的估计。