Collaborative Research: Three decades of foraminiferal assemblages in the Santa Barbara Basin provide a link between present and past

现代释放到大气中的温室气体二氧化碳是过去3000万年来观察到的最高水平。这导致了海洋的巨大变化。这项工作的重点是使用一组成壳生物，浮游有孔虫。有孔虫的碳酸盐外壳存在于海底沉积物中。它们提供了它们生长环境的历史。该项目的目标是利用有孔虫的外壳来更好地了解不同有孔虫物种的丰度如何快速变化以及为什么会响应气候变化。从加州的圣巴巴拉盆地收集的储存样品将创造一个30年的南极有孔虫丰度记录。研究结果将与现代海洋学测量和在更古老的海底沉积物中发现的有孔虫相联系。这将有助于更好地了解气候变化如何在很长一段时间内影响海洋环境，并有助于对未来进行预测。该项目将为学生提供实践研究培训。课堂活动将开发，促进定量和数据可视化技能与现实世界的数据集。有孔虫具有物种特异性的环境偏好，影响它们在水柱和海洋沉积物中的组合。此外，有孔虫壳体的地球化学已成为广泛使用的古海洋学代用指标的基础。然而，对有孔虫化石记录的解释必须从根本上以有孔虫生态学为基础。例如，地球化学代用指标的使用依赖于季节性或栖息地随时间的变化可以忽略不计的假设，违反这种假设可能会导致古海洋学记录中的关键错误。除了评估有孔虫动物群变化的速率和驱动因素外，本研究还将实现以下目标：1）测试季节性变化如何影响有孔虫代理记录的解释，2）评估沉积物陷阱动物群是否代表底层沉积物，以及3）将21世纪世纪有孔虫动物群变化与地质记录相结合。为实现这些目标，将从每两周一次的沉积物捕集器和近每年一次的沉积物岩心取样中收集样品。之所以选择圣巴巴拉盆地，是因为它拥有沉积物捕获材料档案、广泛的重叠观测测量、保存完好的化石记录，并经历了从季节到人为和更长时间尺度的气候振荡。定量组合将得到贝壳子集的稳定同位素和微量元素分析的支持，以测试地球化学替代记录的解释。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响进行评估而被认为值得支持审查标准。

Modern day releases of the greenhouse gas, carbon dioxide, into the atmosphere are the highest observed over the last 30 million years. This has resulted in major changes in the ocean. This work focuses on using a group of shell-forming organisms, planktic foraminifera. The carbonate shells of foraminifera are found in seafloor sediments. They provide a history of the environment in which they grew. The goal of this project is to use the shells of foraminifera to better understand how quickly and why the abundances of different foraminifera species change in response to climate. A thirty-year record of planktic foraminifera abundances will be created from stored samples collected from the Santa Barbara Basin, California. The results will be connected to modern day oceanographic measurements and the foraminifera found in older seafloor sediments. This will allow a better understanding of how climate change has impacted the ocean environment over very long time periods and allow future predictions. This project will provide hands on research training for students. Classroom activities will be developed that promote quantitative and data visualization skills with a real-world dataset. Foraminifera have species-specific environmental preferences that influence their assemblages in the water column and in marine sediments. Moreover, the geochemistry of foraminiferal shells has become the foundation for widely used paleoceanographic proxies. However, interpretation of the fossil foraminiferal record must be fundamentally grounded in foraminiferal ecology. For example, use of geochemical proxies relies on the assumption of negligible change in seasonality or habitat through time, with violations potentially responsible for key errors in the paleoceanographic record. In addition to assessing rates and drivers of foraminiferal faunal change, this research would fulfill goals including: 1) testing how changing seasonality influences interpretations of foraminiferal-based proxy records, 2) evaluating whether sediment trap faunas are representative of underlying sediment, and 3) integrating 21st century foraminiferal faunal change with the geological record. Assemblages from biweekly sediment traps and near-annually resolved samples from a sediment core will be generated to accomplish these goals. Santa Barbara Basin was chosen because it has an archive of sediment trap material, extensive overlapping observational measurements, a well-preserved fossil record, and experiences climatic oscillations at timescales from seasonal to anthropogenic and longer. Quantitative assemblages will be supported by stable isotope and trace elemental analyses of a subset of shells to test interpretations of geochemical proxy records.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.