Collaborative Research: Using Ca, Sr, Mg, and Fe isotope proxies to constrain redox and continental weathering during Ocean Anoxic Event 2

大气中二氧化碳的迅速增加可能导致全球海洋的变化，包括酸化加剧，氧气减少，动植物生命显著减少。该项目的科学家们对9400万年前海洋化学和全球气候的变化很感兴趣，当时大气中的二氧化碳比地球现在的大气多5倍，而且浓度变化很大。研究人员正在测量得克萨斯州鹰福特集团岩石中锶、钙、镁和铁的同位素，这些岩石是由古老的海床形成的。这些结果有助于更好地理解导致和维持那段时期全球变暖的因素，并揭示出对当今气候变化的影响。这项研究正在帮助一名来自代表性不足群体的博士生和一名职业生涯早期的女科学家的职业发展。博物馆正在制作一场关于气候和能源的展览，向公众展示这项工作。晚白垩世海洋缺氧事件2(OAE2)是大气中二氧化碳含量居高不下并随之而来的全球气候变暖的持续时期。全球变暖如何与火山活动相关，以及对大陆风化和全球海洋化学的连锁影响，仍然是悬而未决的问题。来自德克萨斯州鹰福特集团的一个完整的OAE2地层剖面正在检查锶、钙、镁和铁的同位素。这些元素系统中的每一个都记录了有关全球海洋环境和气候变化的不同化学信息。基于同位素数据的数值物质平衡模型被用来约束对全球海洋的输入和输出，以及火山活动和大陆风化之间的反馈。这些成果为进一步研究海洋缺氧和过去地质上的重大气候变化的原因提供了一个框架，并使人们能够更好地了解导致未来气候变化的因素。该项目的更广泛影响包括指导和培训来自代表性不足群体的学生，以及就气候和能源之间的联系进行公众宣传。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Rapid increases of carbon dioxide in the atmosphere can lead to changes in the global ocean, including increased acidification, lower oxygen, and significantly reduced plant and animal life. This project’s scientists are interested in changes in ocean chemistry and global climate 94 million years ago when the atmosphere had up to 5 times more carbon dioxide than Earth’s present atmosphere, and the concentrations varied dramatically. The researchers are measuring isotopes of strontium, calcium, magnesium, and iron in rocks from the Eagle Ford Group in Texas that formed from an ancient seabed. The results are leading to a better understanding of the factors that led to and sustained that period of global warming, and they are revealing implications for present-day climate change. This research is aiding the career development of a Ph.D. student from an underrepresented group and an early career female scientist. A museum exhibit on climate and energy is being created to outreach to the public about this work.The Late Cretaceous Ocean Anoxic Event 2 (OAE2) was a sustained period of high atmospheric carbon dioxide and consequent warming of the global climate. How global warming is related to volcanic activity, and the cascading effects on continental weathering and global ocean chemistry, remain open questions. A complete stratigraphic section through OAE2 from the Eagle Ford Group in Texas is being examined for Sr, Ca, Mg, and Fe isotopes. Each of these element systems record distinct chemical information on the global ocean environment and on changing climate. Numerical mass balance models based on the isotope data are being employed to constrain the inputs and outputs to the global ocean and the feedback between volcanic activity and continental weathering. Results are providing a framework for further examination of the causes of ocean anoxia and substantial climate change in the geological past, and are allowing a better understanding of the factors contributing to future climate change. Broader impacts of this project include mentoring and training students from underrepresented groups and public outreach about the links between climate and energy.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.