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.

中文翻译：

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边缘生活：寒武纪海洋领域和氧合


显生代初期见证了两个生物事件，为即将到来的所有生命奠定了基础：（a） 寒武纪大爆发（大多数海洋无脊椎动物门的出现）和 （b） 大奥陶纪生物多样化事件 （GOBE），随后海洋生物多样性的大量积累。在这里，我们研究了从埃迪卡拉纪晚期到奥陶纪早期对海洋环境和生态系统的理解现状，这跨越了这个重要的生物学时期。通过对现有的地球化学、矿物学、沉积学和化石记录的汇编和回顾，我们认为这个时期是持续的低水平和可变的海洋氧气水平之一，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处于边缘——有足够的氧气来维持它们，但长期存在环境压力源的风险，可能会压垮它们。▪我们回顾了目前寒武纪和早奥陶纪时期的地球化学和古生物学研究。▪海洋领域的低氧水平和振荡的氧气水平促进了多样化和进化创新，但也推动了几次灭绝事件。▪Taphonomic 模式和海洋自生途径是寒武纪的丰富是由海洋的含氧量持续低于今天的海洋支持的。