Determining the nature and drivers of Earth's first metazoan radiation and subsequent extinction: The Cambrian 'Explosion' and Sinsk Event

确定地球第一次后生动物辐射和随后的灭绝的性质和驱动因素：寒武纪“爆炸”和辛斯克事件

• 批准号: NE/Z000122/1
• 负责人: Rachel Wood
• 金额: $ 106.97万
• 依托单位: University of Edinburgh
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2024
• 资助国家: 英国
• 起止时间: 2024 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=NE%2FZ000122%2F1
• 关键词: Determining; nature; drivers; Earth; first

The Cambrian Radiation, starting ca. 540 million years ago (Ma), marks the appearance of abundant and diverse animals (metazoans) in the fossil record. This radiation may have been driven by oscillating ocean oxygenation and productivity events, but was terminated by the first mass extinction, the 'Sinsk Event', ca. 513 Ma. The Sinsk Event is considered to have been a hyperthermal interval of widespread ocean anoxia that reset the trajectory for all subsequent metazoan life. However, despite its significance for the course of Earth's habitability and the evolution of complex life, little is known about the drivers of this event, or which environmental factors controlled extinction selectivity. We hypothesise that it was low oceanic sulphate levels that promoted oscillating oxygenation, so creating pulsed metazoan radiations, but paradoxically this also made the early Cambrian shallow ocean highly susceptible to anoxia in response to global warming, thereby terminating these radiations with a profound extinction. We propose an ambitious integrated palaeobiological, geochemical and modelling approach to unravel the controlling processes of radiations, and the consequences of the enigmatic, but highly significant, Sinsk Event. By comparing the drivers of the Cambrian Radiation with those of its demise, we will address a fundamental motivating question: Did low sulphate seas both promote radiations and drive extinctions through Earth History?

寒武纪辐射，始于大约。 5.4亿年前（Ma），标志着化石记录中出现了丰富多样的动物（后生动物）。这种辐射可能是由海洋氧合和生产力振荡事件驱动的，但因第一次大规模灭绝“辛斯克事件”而终止。第513章辛斯克事件被认为是大范围海洋缺氧的高温区间，它重置了所有后续后生动物生命的轨迹。然而，尽管它对地球的宜居性过程和复杂生命的进化具有重要意义，但人们对这一事件的驱动因素或哪些环境因素控制灭绝选择性知之甚少。我们假设，低海洋硫酸盐水平促进了振荡氧合，从而产生脉冲后生动物辐射，但矛盾的是，这也使得寒武纪早期浅海极易因全球变暖而缺氧，从而终止这些辐射并导致严重灭绝。我们提出了一种雄心勃勃的综合古生物学、地球化学和建模方法，以揭示辐射的控制过程，以及神秘但非常重要的辛斯克事件的后果。通过比较寒武纪辐射的驱动因素及其消亡的驱动因素，我们将解决一个基本的激励问题：在地球历史上，低硫酸盐海洋是否既促进了辐射又导致了灭绝？