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

该研究小组的目标是利用马达加斯加西北部和西南部洞穴中的洞穴来重建南半球热带遗址的晚更新世和全新世气候，并研究气候在岛上生态系统持续变化中的作用。利用之前收集的样本，研究人员计划从最后一次冰川盛期(26,000年前)到现在的高分辨率(接近年度分辨率)分析中构建具有特殊气候意义的时期(例如，4.2 ka事件，年轻仙女木)的高分辨率(十年)气候记录。研究人员将在洞穴三角洲碳-13显著变化的一段时间内从洞穴中提取有机质，并测量生物标记物的浓度，以检验新开发的关于马达加斯加大型动物消失的“生存转移假说”。研究人员将研究洞穴状流体包裹体水同位素，结合碳酸盐氧同位素，作为估算马达加斯加西南部过去11.7万年和马达加斯加西北部过去2.6万年古温度的工具。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。这些资料将有助于理解热带间辐合区(ITCZ)迁移、西印度洋海表温度(SST)和区域降水的影响。特别是，该项目将调查南北半球的印度洋季风在不同的时间尺度上是同相还是异相，并测试目前关于热带降雨量变化的假设。潜在的更广泛的影响包括整合古气候学、人类学和生物学领域的科学，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。研究小组将制作教育材料和为普通观众准备的展品，以提高公众对齐马纳佩索塞国家公园的自然历史、生物多样性和物种灭绝事件的认识。该项目将有助于更好地了解十年尺度气候变化的原因，这有助于预测一个国家可能发生的降雨量变化，这个国家经历了每年一次的严重干旱和洪水，并依靠自给自足的农业生存。该项目包括支持一名在美国从事早期职业的女性博士后学者，以及与马达加斯加科学家和学生合作。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。

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.