The Ediacaran biota were soft-bodied organisms, many with enigmatic phylogenetic placement and ecology, living in marine environments between 574 and 539 million years ago. Some studies hypothesize a metazoan affinity and aerobic metabolism for these taxa, whereas others propose a fundamentally separate taxonomic grouping and a reliance on chemoautotrophy. To distinguish between these hypotheses and test the redox-sensitivity of Ediacaran organisms, here we present a high-resolution local and global redox dataset from carbonates that contain in situ Ediacaran fossils from Siberia. Cerium anomalies are consistently >1, indicating that local environments, where a diverse Ediacaran assemblage is preserved in situ as nodules and carbonaceous compressions, were pervasively anoxic. Additionally, δ²³⁸U values match other terminal Ediacaran sections, indicating widespread marine euxinia. These data suggest that some Ediacaran biotas were tolerant of at least intermittent anoxia, and thus had the capacity for a facultatively anaerobic lifestyle. Alternatively, these soft-bodied Ediacara organisms may have colonized the seafloor during brief oxygenation events not recorded by redox proxy data. Broad temporal correlations between carbon, sulfur, and uranium isotopes further highlight the dynamic redox landscape of Ediacaran-Cambrian evolutionary events.

埃迪卡拉生物群是软体生物，其中许多具有神秘的系统发育位置和生态学，生活在 574 至 5.39 亿年前的海洋环境中。一些研究假设这些类群具有后生动物亲和力和有氧代谢，而另一些研究则提出了一个基本独立的分类群和对化学自养的依赖。为了区分这些假设并测试埃迪卡拉纪生物体的氧化还原敏感性，我们在这里展示了一个高分辨率的局部和全球氧化还原数据集，这些数据集来自碳酸盐岩，其中包含来自西伯利亚的原位埃迪卡拉纪化石。铈异常值始终大于 1，表明当地环境普遍缺氧，在当地环境中，多样化的埃迪卡拉纪组合以结核和碳质压缩的形式原位保存。此外，δ ²³⁸U 值与其他末期埃迪卡拉纪剖面相匹配，表明广泛存在的海洋 euxinia。这些数据表明，一些埃迪卡拉纪生物群至少可以耐受间歇性缺氧，因此具有兼性厌氧生活方式的能力。或者，这些软体埃迪卡拉生物可能在氧化还原代理数据未记录的短暂充氧事件期间在海底定居。碳、硫和铀同位素之间广泛的时间相关性进一步突出了埃迪卡拉纪-寒武纪演化事件的动态氧化还原景观。