Collaborative Research: Reconstructions of Southern Caribbean Climate Variability using Contemporaneous and Co-Located Corals and Speleothems

来自古气候替代记录的历史和古代气候数据可以提供必要的长期气候背景，以支持加勒比沿海社区准备、适应和/或减轻人为气候变化的众多影响。该项目将研究来自干旱的南加勒比海库拉索岛的珊瑚礁生态系统和洞穴环境中的珊瑚和洞穴碳酸盐。这些碳酸盐的地球化学分析和年代测定将被用来产生当地温度和干旱的记录，这些记录跨越了从上一次冰川盛期(约20000年前)到现在地球变暖的时间间隔。将这些地球化学分析与对现代珊瑚礁和洞穴环境的监测和数值模拟结合起来，将有助于确定加勒比海气候在过去的变化程度，以及它们在调节全球气候从季节到冰川-间冰期时间尺度上所发挥的作用。拟议的研究提供了一个独特的机会，可以开发和应用综合办法，在一个研究相对较少的地点了解陆地和海洋气候变异性的同年档案。这项研究的更广泛影响包括通过社区影响的地球科学课程开发和为从K-12到博士后水平的学生提供分级指导机会来传播重大发现。例如，这项研究将通过与加勒比生物多样性研究和管理基金会(CARMABI)建立有针对性的跨机构合作伙伴关系，为库拉索大学的学生提供研究交流机会，在该基金会中，本科生将在佐治亚理工学院和范德比尔特校区工作，在那里，他们将被整合到一个由个人主管、博士后、研究生和本科生组成的多元化、多机构团队。加勒比海的人为气候变化预计将延长季节性暖期，增加暴雨事件的频率和强度，并增加长期干旱的时间。加勒比海北部和西部热带潮湿的洞穴和珊瑚碳酸盐的古气候记录说明了过去几千年来相关的气候驱动因素和遥相关关系，为这些预测提供了背景。然而，值得注意的是，干旱的南加勒比海地区没有同样广泛和信息丰富的记录。该项目将编制来自库拉索的准确的同址珊瑚和洞穴群替代温度和水文气候记录，将这些记录与其他区域和全球替代记录相结合，并在了解陆地和海洋生态系统中的碳酸盐矿物如何记录该区域过去的环境变化方面取得革命性进展。微量元素与钙的比值(如：锶/钙、镁/钙、钡/钙等)和传统的稳定同位素(δ18O、δ13C等)从活跃沉淀的石笋、滴水、现代珊瑚骨骼和海水，将进一步与代理系统模型和仪器数据相结合，以确定陆地和海洋气候在季节性到年代际时间尺度上的主要驱动因素。这一理解将被应用于联合解释水文气候和海温的洞穴和珊瑚替代记录，并制定自上次冰川消融以来的季节性到千年气候演变的全面图景。这项工作包括开发用于联合分析洞穴沉积物和珊瑚碳酸盐的最佳U-Th测年技术、活跃海水和洞穴监测，以及开发和应用新的地球化学替代物，包括通过碰撞池多收集器电感耦合等离子体质谱分析洞穴中钙同位素定量降水替代物的新方法。该奖项由地球科学部和大气与地球空间科学部共同资助，由地球科学部和大气和地球空间科学部通过古气候展望现在和预测的气候计划以及地球科学部的基金共同资助，用于支持各种机构类型提高研究能力、能力和基础设施的项目，如地球观测组织拥抱DCL所概述的。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。

Historical and ancient climate data from paleoclimate proxy records can provide the long-term climate context necessary to support coastal Caribbean communities in preparing for, adapting to, and/or mitigating the numerous impacts of anthropogenic climate change. This project will study coral and speleothem carbonates from reef ecosystems and cave environments on the island of Curaçao in the arid Southern Caribbean. Geochemical analyses and dating of these carbonates will be used to generate records of local temperature and aridity that span the interval as Earth warmed from the Last Glacial Maximum (~20 thousand years ago) to present. Coupling these geochemical analyses with monitoring of modern reef and cave environments and numerical modeling will help determine the extent to which Caribbean Sea climates have varied in the past and the role that they play in mediating global climate on seasonal to glacial-interglacial timescales. The proposed research presents a unique opportunity to develop and apply integrated approaches to understand coeval archives of terrestrial and marine climate variability at a single, relatively understudied location. Broader impacts of this research include the dissemination of major findings through community-influenced geoscience curricula development and tiered mentorship opportunities for students from the K-12 through postdoctoral levels. For example, the research will support research exchange opportunities for University of Curaçao students through a targeted cross-institutional partnership with the Caribbean Research and Management of Biodiversity (CARMABI) foundation, in which undergraduate students will work on the Georgia Tech and Vanderbilt campuses where they will be integrated into a diverse, multi-institutional team of PIs, postdocs, and graduate and undergraduate students.Anthropogenic climate change in the Caribbean Sea is projected to extend seasonal warm periods, increase the frequency and intensity of heavy rainfall events, and increase periods of prolonged drought. Paleoclimate records from speleothem and coral carbonates from the wet tropical Northern and Western Caribbean have provided context for these projections by illustrating the relevant climate drivers and teleconnections over the past several thousand years. However, equally extensive and informative records are notably absent from the arid Southern Caribbean. This project will develop precisely dated, co-located coral and speleothem proxy temperature and hydroclimate records from Curaçao, synthesize these records with other regional and global proxies, and make transformative progress in the understanding of how carbonate minerals in terrestrial and marine ecosystems record past environmental change in this region. Trace element-to-calcium ratios (i.e. Sr/Ca, Mg/Ca, Ba/Ca, etc.) and traditional stable isotopes (δ18O, δ13C, etc.) from actively-precipitating stalagmites, drip waters, modern coral skeletons, and seawater will be further integrated with proxy system models and instrumental data to fingerprint the dominant drivers of terrestrial and marine climate on seasonal to decadal timescales. This understanding will be applied to jointly interpret speleothem and coral proxy records of hydroclimate and SST and develop a comprehensive picture of seasonal to millennial climate evolution since the last deglaciation. This work includes the development of optimal U-Th dating techniques to jointly analyze speleothem and coral carbonates, active seawater and cave monitoring, and the development and application of novel geochemical proxies, including new methods for the analysis of the calcium isotope quantitative precipitation proxy in speleothems via collision cell multi-collector ICP-MS. This award is co-funded by the Division of Earth Sciences and Division of Atmospheric and Geospace Sciences by way of the Paleo Perspectives on Present and Projected Climate Program, as well as the Division of Earth Sciences funds for support of projects that increase research capabilities, capacity and infrastructure at a wide variety of institution types, as outlined in the GEO EMBRACE DCL.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.