Collaborative Research: P2C2--MADagascar Caves And Paleoclimate II (MADCAP II), Continuing Study of Climate Variability in the Southern Hemisphere of the Western Indian Ocean

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The research team aims to build upon previous research using speleothems from caves in northwest and southwest Madagascar to reconstruct Late Pleistocene and Holocene climate from a Southern Hemisphere tropical site and to examine the role of climate in the ongoing alteration of the island’s ecosystems. Using previously collected samples, the researchers plan to construct high-resolution (decadal) multiproxy climate records from the Last Glacial Maximum (26,000 years ago) to the present from high-resolution (near annual resolution) analyses for periods of particular climatic interest (e.g., the 4.2 ka event, Younger Dryas). The researchers will extract organic matter from the speleothems across an interval of marked change in speleothem delta Carbon-13 and measure biomarker concentrations and the same to test a newly developed “subsistence shift hypothesis” for the disappearance of Madagascar’s megafauna. Speleothem fluid inclusion water isotopes, combined with carbonate Oxygen isotopes, will be examined as a tool to estimate paleotemperatures over the past 117,000 years for southwest Madagascar and the past 26,000 years for northwest Madagascar.The goal of the project is to produce long, high resolution records of climate from the Southern Hemisphere tropics. These data will aid in understanding the influences of Inter Tropical Convergence Zone (ITCZ) migration, western Indian Ocean sea-surface temperature (SST), and regional precipitation. In particular the project will investigate whether the Indian Ocean Monsoon in the Northern versus Southern Hemispheres vary in or out of phase at various timescales and test current hypotheses on tropical rainfall variation.The potential Broader Impacts include the integration of science across the fields of paleoclimatology, anthropology, and biology to provide background climate data needed for interpreting the impact of climate on a variety of fossil communities of the past. The research team will produce educational materials and exhibits prepared for a general audience to heighten public awareness of Tsimanampesotse National Park’s natural history, biodiversity, and extinction events. The project will help develop a better understanding of the causes of decadal-scale climate variability which can aid in forecasting possible changes in rainfall in a country that experiences severe drought and flooding on inter-annual time scales and relies on subsistence farming for survival.This project includes supporting an early career female post-doctoral scholar in the United States and collaboration with Malagasy scientists and students as well.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.