P2C2: A Speleothem and Cave Monitoring Research Program to Reconstruct the Paleoclimatology of the Yucatan Peninsula--Testing Modes and Causes of Variability in the North American

尽管观测到的水文循环加剧，包括干旱、洪水和热带气旋等极端事件的发生率增加，但历史记录不够长且不确定，无法将观测到的特定极端水文事件确切地归因于人为原因和/或气候变率的内部模式。该项目旨在从位于尤卡坦半岛（加勒比海和墨西哥湾地区）的石笋中获取降水记录，并通过将这些记录与气候模式模拟相结合，研究热带水文气候变化的潜在因果机制。研究人员将分析多种示踪剂，包括氧、碳同位素和微量元素，以重建加勒比海和墨西哥湾地区在全新世、末次冰期和海洋同位素阶段8-9的关键气候时期的降水变化。此外，他们将扩大2014年开始的地表和洞穴环境和地球化学监测系统，以研究当地降雨量与降水氧同位素和石笋同位素和元素组成之间的关系。新的监测系统将包括实地考察，以了解植被变化和先前方解石降水对石笋碳同位素组成的作用。与尤卡坦半岛新的石笋古气候记录相结合的监测将有助于测试各种假设，这些假设涉及石笋稳定同位素和元素组成的环境控制，玛雅文明发展中干旱的作用，以及海因里希事件（寒冷间隔）与加勒比海北部和墨西哥湾地区降水减少之间的潜在联系。潜在的更广泛的影响包括在人口稠密和脆弱的地理区域（加勒比海和墨西哥湾）对水文气候变率和热带气旋的特征和更好的理解，超出仪器记录。其他更广泛的影响包括对两名博士生的科学培训、指导和专业发展，其中一名是马萨诸塞大学的美国原住民女学生，另一名是研究人员将通过aguu - bridge项目招募的学生。该项目还将支持两名职业生涯早期和中期的研究人员。此外，研究人员和学生将参与公共宣传活动，包括为里约热内卢秘密洞穴（尤卡坦半岛，墨西哥）工作人员进行科学讲座。以前的洞穴监测工作和古气候研究已经成功地纳入了洞穴保护工作，以及导游每年与数千名游客分享的信息。这个古气候研究项目将促进国际合作以及与当地研究人员和社区的接触。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。

Despite the observed intensification of the hydrological cycle including the increased incidence of drought, flooding and extreme events such as tropical cyclones, the historical record is insufficiently long and uncertain to enable the firm attribution of specific observed extreme hydrological events to an anthropogenic cause and/or to internal modes of climate variability. This project aims at producing precipitation records from stalagmites located in the Yucatan Peninsula (Caribbean and Gulf of Mexico regions), and at examining underlying causal mechanisms of tropical hydroclimate change by integration of these records with climate model simulations. The researchers will analyze multiple tracers including Oxygen and Carbon isotopes and trace elements to reconstruct precipitation variability in the Caribbean and Gulf of Mexico regions during key climate periods: the Holocene, the last glacial and during marine isotope stages 8-9. In addition, they will expand an environmental and geochemical monitoring system of surface and cave conditions that started in the year 2014, to investigate the relationship between local precipitation amount, and the Oxygen isotopes of precipitation and stalagmite isotopic and elemental composition. The new monitoring system will include fieldwork to understand the role of vegetation shifts and prior calcite precipitation on the carbon isotopic composition of stalagmites. The monitoring, in conjunction, with the new stalagmite paleoclimate records from the Yucatan Peninsula would help test various hypotheses concerning the environmental controls of the stable isotopic and elemental composition of stalagmites, the role of drought in the development of the Maya civilization, and potential links between Heinrich events (cold intervals) and precipitation declines in the northern Caribbean and Gulf of Mexico region. The potential Broader Impacts include a characterization and better understanding of hydroclimate variability and tropical cyclones beyond the instrumental record in a densely and vulnerable geographic area (Caribbean and Gulf of Mexico). Other Broader Impacts include the scientific training, mentorship and professional development of two Ph.D students including one female Native American student at UMASS and a second student that the researchers will recruit through the AGU-Bridge program. The project will also support two early and mid-career researchers. Additionally, the researchers and students will engage in public outreach activities including scientific lectures for the Rio Secreto Cave (Yucatan Peninsula, Mexico) staff. Previous cave monitoring work and paleoclimate studies from this cave have been successfully incorporated in the cave conservation efforts, and in the information shared by tour-guides with thousands of visitors per year. This paleoclimate research program will foster international collaborations and engagement with local researchers and communities.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.