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

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.