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

来自古气候代理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。该项目将研究加勒比南部干旱地区库拉帕拉奥岛珊瑚礁生态系统和洞穴环境中的珊瑚和岩洞碳酸盐。这些碳酸盐的地球化学分析和年代测定将用于生成当地温度和干旱的记录，这些记录跨越了地球从末次冰期（~2万年前）到现在变暖的这段时间。将这些地球化学分析与对现代珊瑚礁和洞穴环境的监测以及数值模拟相结合，将有助于确定加勒比海气候在过去的变化程度，以及它们在季节性到冰期-间冰期时间尺度上调解全球气候所起的作用。提出的研究提供了一个独特的机会，可以开发和应用综合方法，在一个相对研究不足的单一地点了解陆地和海洋气候变率的同期档案。本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传播主要发现，并为从K-12到博士后水平的学生提供分层指导机会。例如，该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，为库拉帕拉索大学的学生提供研究交流机会，在该合作伙伴关系中，本科生将在佐治亚理工学院和范德比尔特大学校园工作，在那里他们将融入一个由pi、博士后、研究生和本科生组成的多元化、多机构的团队。预估加勒比海的人为气候变化将延长季节性温暖期，增加强降雨事件的频率和强度，并增加长期干旱期。来自潮湿热带北加勒比海和西加勒比海的岩洞和珊瑚碳酸盐的古气候记录通过说明过去几千年的相关气候驱动因素和遥相关，为这些预估提供了背景。然而，在干旱的南加勒比地区明显缺乏同样广泛和翔实的记录。该项目将从库拉帕拉索获得准确年代、同地的珊瑚和岩洞替代温度和水文气候记录，并将这些记录与其他区域和全球替代记录综合起来，在了解陆地和海洋生态系统中的碳酸盐矿物如何记录该地区过去的环境变化方面取得革命性进展。将进一步结合活跃降水石笋、滴水、现代珊瑚骨架和海水的微量元素/钙比值（Sr/Ca、Mg/Ca、Ba/Ca等）和传统稳定同位素（δ18O、δ13C等），结合代理系统模型和仪器数据，在季节至年代际尺度上识别陆地和海洋气候的主导驱动因素。这一认识将应用于联合解释洞穴和珊瑚的水文气候和海温代用记录，并发展出自最后一次消冰期以来的季节至千年气候演变的综合图景。这项工作包括开发最佳U-Th测年技术，以联合分析洞穴和珊瑚碳酸盐，活性海水和洞穴监测，以及开发和应用新的地球化学代用物，包括通过碰撞电池多收集器ICP-MS分析洞穴中钙同位素定量降水代用物的新方法。该奖项由地球科学部和大气与地球空间科学部共同资助，通过“当前和预测气候项目的古视角”，以及地球科学部的基金，用于支持在各种机构类型中提高研究能力、能力和基础设施的项目，如GEO EMBRACE DCL所述。该奖项反映了美国国家科学基金会的法定使命，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.