Collaborative Research: Constraining Planktic Foraminiferal Ecology Using Compound Specific Isotope Analysis of Amino Acids

合作研究：利用氨基酸的复合特定同位素分析来限制浮游有孔虫生态

• 批准号: 2303609
• 负责人: Matthew McCarthy
• 金额: $ 13.12万
• 依托单位: University of California-Santa Cruz
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2303609&HistoricalAwards=false
• 关键词: Collaborative; Research; Constraining; Planktic; Foraminiferal

Current climate change is unique in human history. To understand how the Earth and life on it responds to comparable change it is necessary to look millions of years in the past. A huge amount of what we know about past climate comes from the fossils of marine plankton. Specifically, a group of single-celled organisms called foraminifera. Foraminifera make tiny fossil shells which capture the chemistry of the water they grew in. As a result, they can be used to reconstruct ancient ocean waters and climate. To use the fossil shells of foraminifera to their greatest effect, the ecology of the living creature must be understood. Variables like what the foraminifera ate, what depth it lived at, and whether it had symbionts will all impact how shell chemistry is interpreted. Compound-specific nitrogen and carbon isotopes of specific amino acids (CSI-AA) represent a unique approach to study these variables in living plankton. This proposal would test how well this approach can be applied to fossil shells. If successful, this would provide powerful ways to describe the ecology of long extinct planktic foraminifera. In doing so, one may better understand the records they hold of Earth’s past. The project broader impacts include support for a postdoctoral researcher, development of a career-opportunities workshop to introduce students from Primarily Undergraduate Institutions to geoscience research, and content contributions to a summer program for at-risk STEM transfer students at UC Santa Cruz. Specifically, this project will investigate and develop multiple aspects of CSI-AA to better understand the species-level ecology of planktic foraminifera. This is key to generating paleoclimate and paleoceanographic records that can contextualize the Ocean’s future climate and trajectory. The proposed project will use CSI-AA to constrain three key aspects of planktic foraminiferal ecology: depth habitat, diet, and symbiosis. CSI-AA from shell-bound organics will be used in foraminifera for the first time to refine species-level inferences about these ecological traits. First CSI-AA applications in extant species will be ground-truthed using plankton tows, sediment traps, and recent sedimentary samples from the Santa Barbara Basin. Lessons learned will then be applied deeper into the fossil record to elucidate the trophic ecology of extinct foraminifera. Finally, amino acid molar ratios and racemization (the diagnostic shift between amino acid forms which occurs with fossil age) will be used to assess amino acid preservation in fossils and ultimately test the limits of this approach by targeting a suite of abundant species from the Miocene, Eocene, and Cretaceous.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.

目前的气候变化在人类历史上是独一无二的。要了解地球和地球上的生命如何对类似的变化做出反应，有必要看看过去数百万年的情况。我们对过去气候的大量了解来自海洋浮游生物的化石。具体来说，是一种叫做有孔虫的单细胞生物。有孔虫制造微小的贝壳化石，捕捉它们生长的水的化学成分。因此，它们可以用来重建古代海洋沃茨和气候。为了最大限度地利用有孔虫的化石壳，必须了解生物的生态学。像有孔虫吃什么，它生活在什么深度，以及它是否有共生体这样的变量都将影响如何解释外壳化学。化合物特定的氮和碳同位素的特定氨基酸（CSI-AA）代表了一种独特的方法来研究这些变量在活浮游生物。这项提议将测试这种方法在多大程度上适用于化石贝壳。如果成功的话，这将为描述长期灭绝的南极有孔虫的生态提供强有力的方法。在这样做的过程中，你可以更好地理解他们所持有的地球过去的记录。该项目更广泛的影响包括对博士后研究人员的支持，职业机会研讨会的发展，以介绍学生从小学本科院校地球科学研究，以及内容贡献的夏季计划在加州大学圣克鲁斯的风险干转学生。具体而言，本项目将调查和开发CSI-AA的多个方面，以更好地了解浮游有孔虫的物种水平生态。这是生成古气候和古海洋学记录的关键，这些记录可以说明海洋未来的气候和轨迹。拟议的项目将使用CSI-AA来限制南极有孔虫生态学的三个关键方面：深度栖息地，饮食和共生。壳结合有机物的CSI-AA将首次用于有孔虫，以完善对这些生态特征的物种水平的推断。第一个CSI-AA应用在现存物种将地面使用浮游生物拖，沉积物陷阱，和最近的沉积样品从圣巴巴拉盆地。然后将吸取的经验教训应用于更深入的化石记录，以阐明灭绝有孔虫的营养生态学。最后，氨基酸摩尔比和外消旋化（随着化石年龄发生的氨基酸形式之间的诊断转变）将用于评估化石中的氨基酸保存，并最终通过针对中新世，始新世，该奖项反映了NSF的法定使命，并被认为值得通过使用基金会的知识产权进行评估来支持。优点和更广泛的影响审查标准。