Collaborative Research: A Continuous 60,000 Year Sediment Record Documenting Abrupt to Precession-Scale Climate Change and Ecosystem Response at Fish Lake UT, Upper CO River Basin

合作研究： 60,000 年的连续沉积物记录记录了科罗拉多州上游流域鱼湖 UT 的突然进动规模的气候变化和生态系统响应

• 批准号: 2102997
• 负责人: Jesse Morris
• 金额: $ 30.04万
• 依托单位: University of Utah
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-09-01 至 2025-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2102997&HistoricalAwards=false
• 关键词: Collaborative; Research; Continuous; 60; 000

Over the last several decades increased drought severity and wildfire intensity around the globe has drawn attention to a need for an improved understanding of how climate change over a human lifetime impacts people, ecosystems, and water resources. Rapid population growth in the arid western US combined with pervasive drought, temperature stress on forests, insect outbreaks, and unprecedented wildfires has negatively impacted people and the economy and focused attention on the need to improve our understanding of the controls and long-term consequences of increased climate stress on these valuable and unique ecosystems. This interdisciplinary project will place the 21st century drought and extreme fire seasons in western North America into a longer-term context as a means to identify likely future scenarios for climate change and ecosystem response. This research will use a long and continuous sediment lake record collected from a headwater lake in the upper Colorado River Basin to investigate past variations in precipitation and temperature, and the impacts these changes had on vegetation, wildfire, forest disturbance, and glaciation with special attention paid to periods of rapid climate change that has happened in the past over timescales relevant to people. This is possible because of the high accumulation rate of Fish Lake sediments of about 18.5 meters over the last 60,000 years producing a 60 foot high section of mud containing things like pollen, charcoal, bug parts, fish bones, and other fossils for researchers to study in addition to the sediment itself and the molecular fossils it preserves. The proposed work includes X-ray Fluorescence (XRF) and CT core scanning to identify abrupt sediment boundaries and characterize the sediment profiles at the highest possible resolution. Changes in precipitation and evaporation will be investigated by water isotope tracers, including leaf wax delta-2H (long and short chain) and chironomid delta-18O. Molecular fossils such as branched glycerol dialkyl glycerol tetraethers (brGDGTs) will be used as way to estimate past summer temperatures through time. Landscape and aquatic ecosystem responses will be studies by using pollen, charcoal, polycyclic aromatic hydrocarbons (PAHs), biogenic silica, and organic carbon, nitrogen and stable isotopes. Watershed erosion and glacial activity of the Fish Lake Plateau will be investigated in new detail with scanning XRF, grainsize, organic matter, biogenic silica, and bulk density. Successful dating of an 11-m long core recovered in 2014 has been demonstrated by radiometric methods, including 210Pb and AMS 14C of terrestrial macrofossils and charcoal, by tephrochronology, and by paleomagnetic measurements.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.

在过去的几十年里，全球干旱严重程度和野火强度的增加引起了人们的注意，需要更好地了解气候变化在人类一生中如何影响人类、生态系统和水资源。美国干旱的西部地区人口快速增长，加上普遍干旱、森林温度压力、昆虫爆发和前所未有的野火，对人民和经济产生了负面影响，并引起人们的关注，需要提高我们对控制措施和长期后果的了解。这些宝贵而独特的生态系统面临着越来越大的气候压力。这个跨学科项目将把北美西部 21 世纪的干旱和极端火灾季节置于更长期的背景下，作为确定气候变化和生态系统响应的未来可能情景的手段。这项研究将利用从科罗拉多河流域上游的一个源头湖泊收集的长期、连续的沉积湖记录来调查过去的降水和温度变化，以及这些变化对植被、野火、森林干扰和冰川作用的影响，并特别关注支付过去在与人类相关的时间尺度上发生的快速气候变化时期。这是可能的，因为鱼湖沉积物在过去 60,000 年中积累速度约为 18.5 米，产生了 60 英尺高的泥浆，其中含有花粉、木炭、虫子部位、鱼骨和其他化石供研究人员研究除了沉积物本身及其保存的分子化石之外。拟议的工作包括 X 射线荧光 (XRF) 和 CT 岩心扫描，以识别突变的沉积物边界并以尽可能高的分辨率表征沉积物剖面。降水和蒸发的变化将通过水同位素示踪剂进行研究，包括叶蜡δ-2H（长链和短链）和摇蚊δ-18O。支链甘油二烷基甘油四醚（brGDGT）等分子化石将被用来估计过去夏季随时间变化的温度。将利用花粉、木炭、多环芳烃 (PAH)、生物二氧化硅以及有机碳、氮和稳定同位素来研究景观和水生生态系统的响应。鱼湖高原的流域侵蚀和冰川活动将通过扫描 XRF、粒度、有机质、生物二氧化硅和堆积密度进行新的详细研究。通过辐射测量方法（包括陆地大型化石和木炭的 210Pb 和 AMS 14C）、岩石年代学和古地磁测量，成功对 2014 年回收的 11 米长岩心进行了年代测定。该奖项反映了 NSF 的法定使命，并被认为是值得的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来提供支持。