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.

当前的气候变化在人类历史上是独一无二的，为了了解地球和地球上的生命如何应对类似的变化，我们有必要回顾数百万年前的气候，我们对过去气候的了解来自于海洋化石。具体来说，一群称为有孔虫的单细胞生物会产生微小的化石壳，这些化石壳捕获了它们生长的水中的化学成分。因此，它们可以用来重建古代海洋水域和气候。的贝壳为了使有孔虫发挥最大作用，必须了解生物的生态学，例如有孔虫吃什么、生活在什么深度以及是否有共生体，这些变量都会影响对特定化合物的氮和碳同位素的解释。特定氨基酸（CSI-AA）代表了研究活体浮游生物中这些变量的独特方法，该提案将测试该方法在化石贝壳上的应用效果，如果成功，这将提供强有力的方法来描述。通过这样做，人们可以更好地了解它们所持有的地球过去的记录，该项目的更广泛影响包括支持博士后研究员、举办职业机会研讨会以向主要本科院校的学生介绍。具体来说，该项目将调查和开发 CSI-AA 的多个方面，以更好地了解物种层面的生态学。这是生成古气候和古海洋记录的关键，这些记录可以了解海洋未来的气候和轨迹。拟议的项目将使用 CSI-AA 来限制浮游有孔虫生态的三个关键方面：深度栖息地、饮食和共生。来自壳结合有机物的 AA 将首次用于有孔虫，以完善有关这些生态特征的物种水平推论。 CSI-AA 在现有应用中的首次应用。将利用浮游生物拖曳、沉积物陷阱和圣巴巴拉盆地的最新沉积样本对物种进行实地调查，然后将所学到的经验教训更深入地应用于化石记录中，以阐明灭绝的有孔虫的营养生态学。外消旋化（随着化石年龄发生的氨基酸形式之间的诊断性转变）将用于评估化石中的氨基酸保存，并最终通过针对一系列丰富的物种来测试这种方法的局限性。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。