Collaborative Research: Oxygen, Ecology and the Cambrian radiation of Animals

合作研究：动物的氧气、生态学和寒武纪辐射哈佛大学大卫·约翰斯顿斯克里普斯海洋研究所的丽莎·莱文寒武纪辐射，基本上所有主要的动物身体计划都出现在5.4亿年前的化石记录中，是地球历史上最重要的进化事件之一。近年来，这一事件的假设触发因素主要集中在捕食活动的增加和世界海洋中氧气水平的增加。我们建议检验这些假设之间的联系。我们推测，肉食性动物(以动物为食的动物)的高需氧量是关键联系。这一假说概述了食肉动物(以其他动物为食的动物)受到低水平大气氧气的限制。随着前寒武纪晚期地球过渡到更富氧的状态，这种生活方式(食肉)和最终寒武纪的爆发接踵而至。在这里，我们将检验这一假说的生物学和地质学预测。通过构建和分析已发表的海洋底栖动物调查数据库，对每种动物的进食方式进行编码，并检查氧气水平和其他环境参数如何影响进食行为，这一生物学预测将得到验证，即氧气限制了动物的肉食行为。氧气在前寒武纪-寒武纪边界附近增加的地质预测，将主要通过从加拿大西北部奥吉尔维、韦内克和麦肯齐山脉壮观的新元古代地层记录中生成沉积地球化学数据(重点是铁、碳和硫)来检验。总之，对寒武纪辐射这一综合因果假说的这两项测试将为这一重要的地球生物学事件提供新的见解。这笔赠款为培训两个层次的研究人员提供了资金。首先，这笔赠款为一名博士后学者提供资金，该学者将在斯克里普斯大学和哈佛大学的首席研究员之间工作，以实现该提案的目标。这位博士后学者还将与海洋科学教育卓越中心合作，在桦树水族馆拍摄的海洋科学展望系列中发表公开演讲。这些是广泛分发的讲座(向1500万个家庭广播；每年约20万次网络观看)，将有助于向公众传播现代全球海洋汇编的结果，并展示古代海洋如何为应对现代海洋学变化提供信息。其次，两名本科生，一名来自哈佛大学，一名来自本科院校，将通过这笔赠款获得加拿大西北部的野外经验和沉积地球化学的实验室经验。

Collaborative Research: Oxygen, Ecology and the Cambrian radiation of AnimalsDavid Johnston, Harvard UniversityLisa Levin, Scripps Institute of OceanographyThe Cambrian radiation, during which essentially all major animal body plans appeared in the fossil record ~540 million years ago, is one of the most important evolutionary events in Earth history. In recent years, hypothesized triggers for this event have focused on a rise in predation and increased levels of oxygen in the world's oceans. We propose to test the linkage between these hypotheses. We postulate that the high oxygen demand of carnivory (animals feeding on animals) is the key linkage. The hypothesis outlines that carnivory (animals eating other animals) was limited by low levels of atmospheric oxygen. As the late Precambrian Earth transitioned to a more oxygenated state, this lifestyle (carnivory) and ultimately the Cambrian explosion ensued. Here, we will test both the biological and geological predictions of this hypothesis. The biological prediction, that oxygen limits carnivory in animals, will be tested by constructing and analyzing a database of published marine bottom dwelling animal surveys, coding how each animal feeds, and examining how oxygen levels and other environmental parameters affect feeding behavior. The geological prediction, that oxygen increased near the Precambrian-Cambrian boundary, will primarily be tested by generating sedimentary geochemical data (focusing on iron, carbon and sulfur) from the spectacular Neoproterozoic stratigraphic record of northwestern Canada in the Ogilvie, Wernecke and Mackenzie Mountains. Together, these two tests of this integrative causal hypothesis for the Cambrian radiation will provide new insight into this important geobiological event. This grant provides funding to train two levels of researchers. First, the grant provides funding for a post-doctoral scholar who will work between the Principal Investigators at Scripps and Harvard to accomplish the goals of the proposal. The post-doctoral scholar will also will work with the Center for Ocean Sciences Education Excellence to deliver a filmed public lecture in the Perspectives on Ocean Sciences series at the Birch Aquarium. These are widely distributed talks (broadcast to 15 million homes; ~200,000 web views per year) and will be instrumental in disseminating the results of the modern global ocean compilation to the public and demonstrating how ancient oceans can inform responses to modern oceanographic change. Second, two undergraduate students, one from Harvard and one from an undergraduate-oriented institution, will gain both field experience in northwest Canada and lab experience in sedimentary geochemistry through this grant.