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

该研究小组旨在利用马达加斯加西北部和西南部洞穴的洞穴沉积物，以先前的研究为基础，从南半球热带地区重建晚更新世和全新世气候，并研究气候在岛屿生态系统持续变化中的作用。 利用以前收集的样本，研究人员计划构建从末次冰期最大期（26，000年前）到现在的高分辨率（近年度分辨率）多代理气候记录，用于特定气候兴趣时期（例如，4.2 ka事件，新仙女木事件）。研究人员将在洞穴沉积物三角洲碳-13显著变化的间隔内从洞穴沉积物中提取有机物，并测量生物标志物浓度，以测试马达加斯加巨型动物消失的新开发的“生存转变假说”。 洞穴流体包裹体水同位素结合碳酸盐氧同位素将被用作估算马达加斯加西南部过去117，000年和马达加斯加西北部过去26，000年古温度的工具。该项目的目标是产生南半球热带气候的长期高分辨率记录。这些数据将有助于了解热带辐合带（ITCZ）迁移，西印度洋海表温度（SST）和区域降水的影响。 特别是，该项目将调查印度洋季风在北方和南半球是否在不同的时间尺度上同相或异相变化，并测试目前关于热带降雨变化的假设。和生物学，以提供解释气候对过去各种化石群落的影响所需的背景气候数据。 该研究小组将为普通观众制作教育材料和展览，以提高公众对齐马南佩索采国家公园自然历史、生物多样性和灭绝事件的认识。该项目将有助于更好地了解十年尺度气候变化的原因，这有助于预测一个在年际时间尺度上经历严重干旱和洪水并依赖自给农业生存的国家的降雨量可能发生的变化。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审查标准。

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.