P2C2:Collaborative Research: Rocky Mountain Ecohydrology During the Eemian Interglacial

该奖项的目标是评估在地球最近的时期Eemian间冰期（开始约130，000年，结束约115，000年前）对落基山脉森林健康的控制？当生长季节的温度超过今天的温度时， 由于Eemian变暖发生在工业化前部分二氧化碳（pCO 2）浓度的背景下，该研究旨在隔离主要树种对生长季节温度的反应，这些温度与AD 2100预测的正常温度相当。该项目利用了最近从科罗拉多斯诺马斯恢复和保存完好的Eemian时代的木材样本，通过与丹佛自然与科学博物馆的合作，该项目可以获得这些样本。 Eemian木材样本提供了一个难得的机会，探索美国西部的森林在过去如何应对比今天高3-5°C的夏季温度？S. 北方森林在全球碳循环中发挥关键作用，并提供重要的大型动物栖息地和生态系统服务。气候变暖、山区水文变化（如融雪时间）和预计将在下个世纪发生的二氧化碳分压升高的同时和耦合影响，导致对该生态系统对全球变化的反应作出了大相径庭的预测。研究人员将对来自落基山脉南部物种的现代和Eemian木材样本进行亚季节分辨率的δ氧-18和碳-13（d18 O和d13 C）同位素测量，这些木材样本在Eemian时期很常见，今天仍然占主导地位。这些木材样品将用于测试生长季节长度、水利用率（即，夏季降雨与融雪）和Eemian期间的水利用效率（即，温暖的温度和低pCO 2）与今天相比（即，“冷”温度和高pCO 2）。这项分析将提供清晰的是否最近的变化，在工厂？水分利用效率是CO2施肥效应或CO2和温度耦合变化的产物。除了同位素测量外，研究人员还将在Eemian和现代强迫下生成嵌套（50公里分辨率）同位素启用的大气环流模型（GCM）模拟，为用于解释代理数据的生态水文和生态生理过程模型提供气候输入。这项研究的成果将评估温度驱动的地表水文变化（雪和土壤过程）、大气环流（北美季风范围和持续时间）和表面/叶片温度联合收割机，以改善或瓦解森林健康，包括美国西部大型野火和树木死亡率的增加。该项目将支持两名早期职业科学家，古气候学、生态学和气候动力学 位于芝加哥的多机构合作将促进稳定同位素地球化学和气候建模的本科生和研究生研究机会，这些研究机会在机构之间发挥作用，是二十一世纪世纪科学培训的基础。此外，还有一个强大的合作与自然和科学丹佛博物馆的研究和教育。

This award's goal is to assess controls on Rocky Mountain forest health during the Eemian-interglacial (beginning ~130,000 and ending ~ 115,000 years ago), the most recent period in Earth?s history when growing season temperatures exceeded those of today. Since the Eemian warming occurred in the context of pre-industrial partial carbon dioxide (pCO2) concentrations, the research aims to isolate the response of dominant tree species to growing season temperatures that are comparable to those predicted to be normal by AD 2100. The project takes advantage of recently recovered and well-preserved Eemian-age wood samples from Snowmass, Colorado available to this project through collaboration with the Denver Museum of Nature and Science. The Eemian wood samples provide a rare opportunity to explore how forests in the western U.S. have responded in the past to summer temperatures ~3-5°C higher than today?s. Boreal forests play a critical role in the global carbon cycle and provide important macrofaunal habitat and ecosystem services. The simultaneous and coupled influences of warming, changes in mountain hydrology (such as the timing of snowmelt) and elevated pCO2 that are predicted to occur over the next century have led to widely disparate projections on the response of this ecosystem to global change. The researchers will make sub-seasonally-resolved delta oxygen-18 and carbon-13 (d18O and d13C) isotopic measurements on modern and Eemian wood samples from species in the southern Rocky Mountains that were common during the Eemian and remain dominant today. These wood samples will be used to test how growing season length, water utilization (i.e., summer rain versus snowmelt) and Water Use Efficiency during the Eemian (i.e., warm temperatures and low pCO2) compare to today (i.e., "cool" temperatures and high pCO2). This analysis will provide clarity on whether recent changes in a plant?s Water Use Efficiency is a product of the CO2 fertilization effect or from coupled changes in CO2 and temperature. In addition to the isotope measurements, the researchers will generate nested (50 km resolution) isotope-enabled general circulation model (GCM) simulations under Eemian and modern forcings to provide climatic inputs for the ecohydrological and ecophysiological process models used to interpret the proxy data. The products of this research will be an assessment of how temperature-driven shifts in surface hydrology (snow and soil processes), atmospheric circulation (North American Monsoon extent and duration), and surface/leaf temperatures combine to improve or disintegrate forest health, including increases in large wildfires and rates of tree mortality in the western U.S.The project will support two early career scientists working at the intersection of paleoclimatology, ecology, and climate dynamics. The Chicago-based multi-institutional collaboration will facilitate undergraduate and graduate research opportunities in stable isotope geochemistry and climate modeling that are leveraged between institutions and are fundamental for twenty-first century scientific training. Additionally, there is a strong collaboration with the Denver Museum of Nature and Science for research and education.