COLLABORATIVE RESEARCH: Ocean Oxidation and the Biosphere During Neoproterozoic Glaciation

合作研究：海洋氧化和新元古代冰川期间的生物圈Susannah Porter（首席PI）;加州圣巴巴拉大学Matthew Hurtgen;西北大学ARRA声明：“这项提案将使用2009年《美国复苏和再投资法案》提供的资金进行奖励。（公法111-5）摘要地球表面氧含量的增加一直被认为是新元古代末期生物创新的驱动力（1000 ~ 5.41亿年前），当时包括动物在内的各种宏观生命首次蓬勃发展。最近的研究表明，大约5.8亿年前海洋氧合的脉冲可能允许动物的进化，但几乎没有考虑到生物学和新元古代早期氧气水平波动之间的关系，特别是跨越Cryogenian（a.k.a.）。?雪球地球？）7.2亿至6.35亿年前的冰川，当时地球可能被冰掩埋。该项目的目的有两个：（1）重建低温冰期期间的氧气水平和生物学;（2）测试氧气水平波动与这段时间观察到的生物群落多样性和组成变化有关的假设。为了实现这些目标，PI将对从挪威北部的斯瓦尔巴群岛和澳大利亚四个独立盆地的连续地层中收集的页岩进行微体古生物学、地球化学和地质年代学分析。总的来说，这些单位跨越了整个低温期冰期。来自斯瓦尔巴特群岛的样本已经收集完毕;来自澳大利亚的样本将在两个野外季节收集，一个在塔斯马尼亚，另一个在澳大利亚大陆。所有分析都将对同一套地层明确的样本进行，从而使生命和氧气可用性的记录能够明确地联系起来，并置于新元古代气候变化的背景下。

Collaborative Research: Ocean Oxidation and the Biosphere during Neoproterozoic GlaciationSusannah Porter (Lead PI); EAR-0922305University of California Santa BarbaraMatthew Hurtgen; EAR-0921913Northwestern UniversityARRA Statement: "This proposal will be awarded using funds made available by the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).ABSTRACTAn increase in Earth surface oxygen levels has long been invoked as a driver of biological innovation at the end of the Neoproterozoic Era (1000 to ~541 million years ago), when diverse macroscopic life, including animals, first flourished. Recent work suggests that a pulse in ocean oxygenation ~580 million years ago may have permitted the evolution of animals, but almost no consideration has been paid to the relationship between biology and fluctuating oxygen levels earlier in the Neoproterozoic, in particular spanning the Cryogenian (a.k.a. ?snowball Earth?) glaciations ~720 to 635 million years ago, when Earth may have been entombed in ice. The aim of this project is two-fold: (1) reconstruct oxygen levels and biology during the Cryogenian glacial interval; and (2) test the hypothesis that fluctuating oxygen levels are linked to changes in the diversity and composition of biological communities observed during this time. To address these goals, the PIs will undertake micropaleontological, geochemical, and geochronologic analyses of shales collected from successions in Svalbard, an archipelago north of Norway, and in four separate basins in Australia. Collectively, these units span the entire interval of Cryogenian glaciation. Samples from Svalbard have already been collected; samples from Australia will be collected during two field seasons, one in Tasmania, the other on the Australian mainland. All analyses will be performed on the same suite of stratigraphically well-defined samples, allowing records of life and oxygen availability to be unambiguously linked and placed within the context of Neoproterozoic climate change.