Integrating novel molecular techniques to disentangle the roles of climate, time, and human agency on the evolution of the Icelandic landscape

整合新颖的分子技术来阐明气候、时间和人类因素对冰岛地貌演变的作用

基本信息

批准号：
1836981
负责人：
Gifford Miller
金额：
$ 93.5万
依托单位：
University of Colorado at Boulder
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2019
资助国家：
美国
起止时间：
2019-06-01 至 2024-11-30
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1836981&HistoricalAwards=false
关键词：
Integrating novel molecular techniques disentangle

项目摘要

Project AbstractNon-Technical Description:Significant uncertainties remain in our ability to predict how ecosystems will respond and landscapes will change as the Arctic continues to warm faster than the global average. We can look to past warm times in recent Earth history to better constrain how the Earth system will respond to warming over the coming century. At the end of the last ice age Earth's orbit was such that the Northern Hemisphere received nearly 10% more solar energy in summer than at present. That extra energy was sufficient to melt almost all Iceland's glaciers, and the Sagas say birch forests extended from the shores to the mountains. Molecular compounds that track changes in temperature, aridity, and vegetation history are contained within the sediment deposited in Icelandic lakes and nearby composite soils over the past 12,000 years. These "proxies" provide a means to accurately reconstruct a continuous history of climate and ecosystem status across Iceland since the end of the last ice age. This research benefits from recent advances in the recovery of DNA from sedimentary archives and in organic geochemistry to isolate biomarkers that track temperature and moisture balance. A pervasive feature of the contemporary Icelandic landscape is widespread soil erosion, but whether that erosion is a result of human settlement and pastoral activity or climate change remains debated. Geochemical proxies related to soil erosion preserved in well-dated lake sediment are targeted to disentangle the roles of climate and humans in Iceland's soil erosion history. This project helps launch an early-career Latino scientist, provides international exposure to a recent PhD as postdoc in a DNA laboratory in Norway, and supports a new PhD student, as well as supporting and mentoring motivated undergraduate students, who gain research experience in a highly relevant field. With an embedded journalist communicating the potential effects of climate change derived from this research to the wider public is enhanced. Technical Description:The Arctic is currently warming twice as fast as the global average with summer temperatures predicted to be 4 to 6 degrees C above late 20th Century averages by the year 2100. Amplified warming in the Arctic is expected to result in a northward shift in woody plants. The increase in woody vegetation will reduce surface albedo and increase atmospheric water vapor, positive feedback mechanisms that are currently poorly constrained in climate models. In Iceland, stratified, securely-dated, lake sediment records span the current interglacial (Holocene) and contain a rich archive of sedimentary ancient DNA (sedaDNA) and lipid biomarker proxies for temperature (brGDGTs), hydrology (delta2-Hwax) and human agency (fecal sterols and PAHs). The analysis of modern soil and lake surface sediment networks will provide calibrations that enhance the community's understanding of these promising new molecular proxies and facilitate the development of regional training sets. Merging the local calibrations with similar measurements downcore in lake sediment and stratified aeolianites will enable reliable reconstructions of past ecosystems and their dependence on summer temperature and hydroclimate. The novel integration of these datasets will provide transformative new insights into 1) how much warmer was the early Holocene in Iceland relative to today, 2) when and to what elevation woody plants established themselves during early Holocene warmth, and 3) to what extent climate, volcanism and/or Norse settlement led to the widespread soil erosion apparent across the Icelandic landscape today. Anticipated results from this project provide key datasets needed to inform policy and improve forecasts of a rapidly warming Arctic.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.

项目摘要非技术描述：随着北极持续变暖速度快于全球平均水平，我们预测生态系统将如何响应以及地貌将如何变化的能力仍然存在很大的不确定性。我们可以回顾近代地球历史上过去的温暖时期，以更好地限制地球系统如何应对下个世纪的变暖。在上一个冰河时代结束时，地球轨道使得北半球在夏季接收到的太阳能比现在多了近 10%。这些额外的能量足以融化几乎所有冰岛冰川，萨加斯说白桦林从海岸延伸到山脉。过去 12,000 年来冰岛湖泊和附近复合土壤中沉积的沉积物中含有跟踪温度、干旱度和植被历史变化的分子化合物。这些“代理”提供了一种准确重建自上一个冰河时代结束以来整个冰岛气候和生态系统状况的连续历史的方法。这项研究受益于从沉积档案中回收 DNA 和有机地球化学领域的最新进展，以分离跟踪温度和湿度平衡的生物标记。当代冰岛景观的一个普遍特征是广泛的土壤侵蚀，但这种侵蚀是否是人类住区和牧区活动或气候变化的结果仍然存在争议。保存在年代久远的湖泊沉积物中的与土壤侵蚀相关的地球化学指标旨在阐明气候和人类在冰岛土壤侵蚀历史中的作用。该项目帮助培养一名职业生涯早期的拉丁裔科学家，为最近在挪威 DNA 实验室担任博士后的博士生提供国际接触机会，并支持一名新的博士生，以及支持和指导有积极性的本科生，让他们在某个领域获得研究经验。高度相关的领域。通过一名嵌入式记者，可以增强向更广泛公众传达这项研究得出的气候变化的潜在影响。技术描述：北极目前变暖速度是全球平均水平的两倍，预计到 2100 年夏季气温将比 20 世纪末平均水平高 4 至 6 摄氏度。北极变暖加剧预计将导致北极地区北移。木本植物。木本植被的增加将降低地表反照率并增加大气水蒸气，这是目前气候模型中很难约束的正反馈机制。在冰岛，分层、年代可靠的湖泊沉积物记录跨越了当前的间冰期（全新世），并包含丰富的沉积古 DNA (sedaDNA) 档案以及温度 (brGDGTs)、水文 (delta2-Hwax) 和人类机构的脂质生物标记物代理（粪便甾醇和多环芳烃）。对现代土壤和湖泊表面沉积物网络的分析将提供校准，以增强社区对这些有前途的新分子代理的理解，并促进区域培训集的开发。将当地校准与湖泊沉积物和分层风成岩中的类似测量相结合，将能够可靠地重建过去的生态系统及其对夏季温度和水文气候的依赖。这些数据集的新颖整合将为以下方面提供变革性的新见解：1）冰岛全新世早期相对于今天温暖了多少，2）木本植物在全新世早期温暖期间何时以及在什么海拔上建立了自己，以及3）气候在多大程度上、火山活动和/或挪威人定居导致今天冰岛景观普遍出现水土流失。该项目的预期结果提供了为政策提供信息并改进对北极迅速变暖的预测所需的关键数据集。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。