Development of Precipitation, Evaporation and Temperature Records from Tropical Lake Sediments and Cave Deposits for the last 700,000 years

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。全球气温上升对人类和生态系统的影响因世界各地而异。在热带地区，受影响主要体现在可用水方面。保存在洞穴和湖泊中的沉积物为热带环境如何应对过去的气候变化提供了关键的见解。这项研究将从秘鲁的洞穴沉积和湖泊沉积物中建立起70万年的记录，以了解全球气候变化如何影响亚马逊盆地上游的降水、温度和湿度。这项工作的发现将适用于理解气候变化在该地区和全球范围内的影响，因为亚马逊是世界上最大的雨林的家园，也是全球碳循环的重要调节者。该项目将整合三所研究型大学和一所本科文理学院的研究人员。本科生将通过拟议工作的所有方面与研究生接触，一名博士后研究员将常驻文理学院，并将与研究型大学的团队合作。此外，科学家将与秘鲁的教职员工和学生合作，建立一个针对地区性洞穴、湖泊和降水的监测项目，以及一个由社区成员领导的旨在气候变化教育的公共外联项目。研究人员将通过开发实践水文学和气候变化模块来扩大少数族裔学生对地球科学的参与，这是密歇根大学地球营的一部分，密歇根大学地球营是一个面向高中生的体验式学习项目。研究人员将结合对一套古气候指标的分析，使用70万年的朱尼恩湖沉积物记录和附近洞穴的沉积物，产生过去70万年来亚马逊盆地上游降水-蒸发平衡和温度的几乎连续的综合记录。2015年，美国国家科学基金会和国际大陆钻探计划资助了朱尼恩湖钻探岩芯的成功采集，并于2019年利用大学资金收集了洞穴沉积物。研究人员将把Junín湖钻探岩芯与由精确U-Th地质年代学确定年代的复合洞穴(CAVE)记录结合在一起，并将利用这些档案建立降水、蒸发和温度的记录，这将使我们的新数据能够与现有记录合成，以研究亚马逊盆地的耦合气候系统(季风强度和大西洋经向翻转环流)、不同边界条件下的气候敏感性，以及在力量大而迅速变化期间的水文变化。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。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).The influence of increasing global temperatures on people and ecosystems varies across the world. In tropical regions, the impact is felt mostly in terms of water availability. Deposits preserved in caves and lakes provide key insights into how tropical environments responded to past climate change. This study will build a 700 thousand year-long record from cave deposits and lake sediments in Peru to understand how a changing global climate affects precipitation, temperature and humidity in the upper reaches of the Amazon Basin. The findings from this work will apply to understanding the impacts of climate change in this region and extend globally, as the Amazon is home to the world’s largest rainforest and an important regulator of the global carbon cycle. This project will integrate researchers at three research universities and one undergraduate liberal arts college. Undergraduate students will interface with graduate students through all aspects of the proposed work, and a postdoctoral fellow will be based at the liberal arts institution and will work with teams at the research universities. In addition, scientists will collaborate with faculty and students in Peru to establish a monitoring program for regional caves, lakes and precipitation, and on a public outreach program aimed at climate change education led by community members. Researchers will expand participation of underrepresented minority students in the Earth sciences through development of a hands-on hydrology and climate change module as part of the University of Michigan Earth Camp, an experiential learning program for high school students.Researchers will combine analyses of a suite of paleoclimate proxies using both the 700,000 year-long Lake Junín sediment record and deposits from nearby caves, to produce a near-continuous, composite record of precipitation-evaporation balance and temperature for the upper Amazon Basin for the last 700,000 years. The National Science Foundation and the International Continental Drilling Program funded the successful collection of the Lake Junín drill core in 2015, and the cave deposits were collected in 2019 using university funds. Researchers will combine the well-dated Lake Junín drill core with a composite speleothem (cave) record dated by precise U-Th geochronology, and will use these archives to build records of precipitation, evaporation, and temperature, that will enable synthesis of our new data with existing records to investigate coupled climate systems in the Amazon Basin (monsoon strength and Atlantic meridional overturning circulation), climate sensitivity under different boundaryconditions, and hydrologic change during periods of large and rapid changes in forcing.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.