Improving High Latitude Foraminiferal Paleoproxies: Insights from Northern California Current Modern and Historical Records

改善高纬度有孔虫古代理：来自北加州当前现代和历史记录的见解

• 批准号: 2306057
• 负责人: Brittany Hupp
• 金额: $ 26.87万
• 依托单位: George Mason University
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2022
• 资助国家: 美国
• 起止时间: 2022-10-01 至 2025-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2306057&HistoricalAwards=false
• 关键词: Improving; Latitude; Foraminiferal; Paleoproxies; Insights

This project will improve our ability to reconstruct past ocean conditions, such as sea surface temperatures, in high-latitude regions. These regions experience a more extreme response to climate change than low-latitude regions. One of the best ways to study past ocean-climate change is by studying fossil plankton called planktic foraminifera or “forams”. Forams are microscopic zooplankton that have existed for over 200 million years and live near the surface of the ocean. As these organisms grow, they build small shells. The shell chemistry records the conditions at the time the shells were formed. When the organism dies, its shell sinks to the seafloor and becomes part of the geological fossil record. Thus, the chemical composition of fossil shells recovered from deep-sea sediments can be used to reconstruct the surface ocean conditions in the past. This study will generate the geochemical-environmental relationships (i.e., calibration equations) used to evaluate fossil foram records. The composition of the shells of living and recently deceased forams collected from the surface ocean will be compared to the conditions and chemical makeup of the seawater they are living in. Samples for this study will include an archive of plankton tow samples from the last decade. Newly collected plankton tow and water samples from throughout the Northern California Current region off the coast of northern California, Oregon, and Washington states will also be studied. Although forams are found globally, this study will focus on constraining geochemical-environmental relationships for species that live in intermediate- to high-latitude regions to better predict how these vulnerable regions will respond to our changing climate. The research team will also investigate how the composition of foram shells may change throughout the organism’s life cycle. This study will help ensure that the calibration equations used to interpret fossil records are accurate. The project includes support for an early career scientist and for undergraduate students. The research team will share the results and scientific process of the research with the public through several public outreach events.The dynamic Northern California Current (NCC) system has been extensively monitored for nearly half a century, through a series of hydrographic transects off the coasts of California, Oregon, and Washington, resulting in a robust archive of plankton tow samples and concurrent environmental data. This study will use historical plankton tow samples, and collect new plankton samples, to further develop a range of trace element/calcium (TE/Ca) paleoproxies for intermediate to high latitude planktic foraminiferal species living in the NCC. Species common to the NCC include temperate and high-latitude genotypes of Globigerina bulloides, Neogloboquadrina pachyderma, N. incompta, N. dutertrei, and Turborotalita quinqueloba. These species are common in higher latitude regions, including the Artic Ocean, where temperature change in response to climate change tends to be greatest. The research objectives are to: 1) establish Mg/Ca-temperature and Na/Ca-salinity calibrations for understudied temperate to polar planktic foraminiferal taxa and investigate the potential for other TE/Ca-environmental relationships, 2) investigate potential vital effects and mechanisms for TE incorporation in planktic foraminiferal shells as they transition from life to death, and 3) characterize the d18O(seawater) signature in the study region and establish species specific seawater foraminiferal calcite isotopic offsets in order to constrain the depth habitats of the study taxa, a critical step to establishing calibrations based on data in a “natural laboratory” setting. The proposed research will further develop novel and existing planktic foraminiferal TE/Ca proxies for use in paleoclimatic and paleoceanographic reconstructions, with particular emphasis on improving our ability to reconstruct past environmental conditions in intermediate to high latitude regions.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.

该项目将提高我们在高纬度地区重建过去的海面温度（例如海面温度）的能力。与低纬度地区相比，这些地区对气候变化的反应更为极端。研究过去的海洋气候变化的最佳方法之一是研究称为浮游有孔虫或“原始孔”的化石浮游生物。孔是已经存在了超过2亿年的微观浮游动物，并且生活在海面附近。随着这些生物的生长，它们会构建小贝壳。壳化学记录了壳形成时的条件。当生物体死亡时，其壳会沉入海底，并成为地质化石记录的一部分。这是从深海沉积物中回收的化石壳的化学成分，可以用来重建表面海洋条件。这项研究将产生用于评估化石原料记录的地球化学环境关系（即校准方程）。将从地面海洋中收集的生物和最近死亡的孔的组成与他们所居住的海水的条件和化学构成。这项研究的样本将包括过去十年的浮游生物拖车样品的档案。还将研究来自北加州北加州北加州，俄勒冈州和华盛顿州北加州当前地区的新收集的浮游生物拖曳和水样。尽管在全球范围内发现了孔，但本研究将重点限制生活在中间至高纬度地区的物种的地球化环境关系，以更好地预测这些脆弱区域将如何响应我们不断变化的气候。研究小组还将调查在整个生物体生命周期中，孔贝壳的组成如何改变。这项研究将有助于确保用于解释化石记录的校准方程是准确的。该项目包括对早期职业科学家和本科生的支持。研究小组将通过几项公共宣传活动与公众分享研究的结果和科学过程。北加州电流（NCC）系统通过一系列水文置换了加利福尼亚州，俄勒冈州和华盛顿的一系列水文样品，从而对近半个世纪进行了广泛监测，从而导致了浮游生物牵引样品型浮游生物和综合环境数据。这项研究将使用历史浮游生物拖放样品，并收集新的浮游生物样品，以进一步开发一系列的痕量元素/钙（TE/CA）古倍型，用于中间至高纬度浮游物种，生活在NCC中。 NCC共有的物种包括Globigerina Bulloides，Neogloboquadrina Pachyderma，N。Commpta，N。Dutertrei和Turborotalita Quinqueloba的温度和高纬度基因型。这些物种在较高的纬度区域（包括货币海洋）中很常见，在这里，响应气候变化的温度变化往往最大。研究目标是：1）建立Mg/Ca-tempure and Na/ca-salinity校准，以了解温度到极性板岩有孔虫类群，并研究其他TE/CA-环境关系的潜力，2）研究在浮游生物壳中的TE保险的潜在生命效果和机制，从生命过渡到死亡和3次签名的d1 and）（）规格特定的海水有孔虫同位素偏移量以限制研究类群的深度栖息地，这是在“自然实验室”环境中基于数据建立校准的关键步骤。拟议的研究将进一步开发出新颖和现有的浮游物质Te/CA代理，用于古气候和古洋野肿学重建，特别强调提高我们重建中级至高纬度地区过去环境条件的能力。该奖项通过评估了NSF的法定范围，反映了NSF的法定范围，并通过评估了Intellitia crotial and Intellit and Intformitial的支持。