A Phosphorus Control on Oceanic Anoxic Events under Greenhouse Climates?

该项目将研究对白垩纪温室海洋的发育、空间范围和缺氧持续时间的控制。具体地说，将研究来自陆架和更深的边缘/盆地地点的高分辨率、多代理记录，覆盖两个不同强度的不同温室情景，以测试轨道对以下情况的影响：1)氧化还原状态：将使用最先进的多代理方法来区分与潜在的Fe和S循环扰动有关的关键水柱氧化还原状态。2)P循环的响应：将利用P形态分布以了解海洋对风化和海洋氧化还原变化的生物地球化学响应。这些记录将揭示陆架和深盆地中氧化还原和P循环之间的反馈，导致我们对过去1.2亿年来地球系统发生的一些最戏剧性的扰动的理解发生了阶段性的变化。反过来，这将为在过去和未来温室条件下的其他海洋缺氧事件中可能操作的通用过程提供信息。

This project will examine controls on the development, spatial extent and duration of anoxia in the Cretaceous greenhouse ocean. Specifically, high resolution, multi-proxy records from shelf and deeper margin/basin sites, covering two contrasting greenhouse scenarios of differing intensity, will be studied to test orbital effects on: 1) Redox state: A state-of-the-art multiproxy approach will be used to distinguish between key water column redox states linked to potential perturbations of the Fe and S cycles.2) Response of the P cycle: P speciation will be utilized in order to understand the ocean biogeochemical response to changes in weathering and ocean redox.These records will unravel feedbacks between redox and P cycling on the shelf and in the deep basins, leading to a step-change in our understanding of some of the most dramatic perturbations to the Earth system of the last 120 million years. This, in turn, will inform on generic processes that likely operated during other episodes of ocean anoxia under past, and potentially future, greenhouse conditions.