Collaborative Research RUI: Decadal cyclicity in NAO proxies from northwest Iceland lake sediments

合作研究 RUI：冰岛西北部湖泊沉积物中 NAO 代理的年代际循环

• 批准号: 1003449
• 负责人: Brad Hubeny
• 金额: $ 12.11万
• 依托单位: Salem State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-10-01 至 2014-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1003449&HistoricalAwards=false
• 关键词: Collaborative; Research; RUI; Decadal; cyclicity

Technical DescriptionThis four-year, field- and lab-intensive work extends the paleo-North Atlantic Oscillation (NAO) record to 2000 years BP, building on existing paleolimnological datasets of pollen, organic and inorganic chemistry, mineral magnetism and particle-size that show strong qualitative linkages with NAO activity on Iceland. It develops new quantitative linkages with the NAO from these same proxies in northwest Iceland lake, soil and stream deposits of the last 2000 years, using calibration datasets of watershed soil and lake sediments derived from current depositional environments. It identifies the specific environmental mechanisms responsible for creating distinct, 80-100 year cycles in the mineral deposits of Icelandic lakes and tests these hypotheses:1. periods of intensified storminess and precipitation on Iceland, such as occur when the NAO index is high and positive, consistently and predictably mobilize minerals from watershed soil reserves and alter lake water characteristics to form distinctive lake sediment deposits, and2. watershed disturbances related to human occupation and land-use increase the amplitude and/or recurrence interval of the decadal cycle, and3. conservation protection of the lakes' watersheds in the last 30 years has resulted in a trend towards that of a pre-occupation state, as documented in the lake sediment geochemistry.Broader impactThe North Atlantic Oscillation (NAO) is part of a global-scale circulation pattern that dominates Northern Hemisphere atmospheric conditions. It is linked to patterns of drought, flooding and severe weather in North America, Europe and the Middle-East. Prior work has shown that the NAO undergoes regular cycles that disturb watershed soils and alter nutrient inflows to lakes and rivers, at least on Iceland. This works uses that lake effect to "see" into the past 2000 years and identify when the NAO was most active. Because human occupation of Iceland began just over 1000 years ago, and this project produces records of change covering the last 2000 years, it offers a unique look at the human role in magnifying the impacts of NAO-related climate changes on fragile landscapes, such as occur in Iceland and in many other previously glaciated regions. By assessing the response of watersheds to repeated climate disturbances, like the NAO, before and after human land use and before and after conservation management, this work provides insight on the usefulness of conservation efforts in mitigating human aspects of climate change. This project also provides much needed research, education, field and laboratory training opportunities for undergraduate and graduate students at institutions with relatively limited research opportunities (Plymouth State University and Salem State College), providing access and engagement with three tier-one, research institutions (U. Maine, U. Colorado and U. Minnesota). Students are involved at every level of the project and learn state-of-the-art interdisciplinary approaches typically practiced at research-oriented institutions. It creates opportunities for students to communicate complex ideas associated with research findings in oral and written publications. The five senior researchers involved in this project also receive training in state-of-the-art cross-disciplinary approaches and applications, which enhances their teaching and research capabilities. This work involves significant use of National Laboratory facilities at LacCore and Large Lakes Observatory and combines efforts of 3 New England campuses, leveraging existing facilities and human resources and building new regional capacity.

这项为期四年的实地和实验室密集型工作将古北大西洋涛动（NAO）记录扩展到2000年BP，建立在现有的花粉，有机和无机化学，矿物磁性和颗粒大小的古湖沼学数据集上，这些数据显示出与冰岛NAO活动的强烈定性联系。它开发了新的定量联系与NAO从这些相同的代理在冰岛西北部的湖泊，土壤和溪流沉积物的过去2000年，使用校准数据集的流域土壤和湖泊沉积物来自当前的沉积环境。它确定了具体的环境机制，负责创造不同的，80-100年的周期在冰岛湖泊的矿藏和测试这些假设：1。在冰岛，当NAO指数高且为正值时，会出现暴雨和降水加剧的时期，持续且可预测地从流域土壤储备中动员矿物质，并改变湖水特征，形成独特的湖泊沉积物沉积，以及2.与人类活动和土地利用相关的流域扰动增加了年代际周期的振幅和/或重现间隔;在过去的30年里，对湖泊流域的保护已经导致了一种趋势，即一个预先占领的状态，在湖泊沉积物地球化学记录。更广泛的影响北大西洋涛动（NAO）是一个全球尺度的环流模式的一部分，主导着北方的大气条件。它与北美、欧洲和中东的干旱、洪水和恶劣天气模式有关。先前的研究表明，NAO经历了有规律的循环，扰乱了流域土壤，改变了流入湖泊和河流的营养物质，至少在冰岛是这样。这项工作利用湖泊效应来“看到”过去2000年，并确定NAO最活跃的时间。由于人类对冰岛的占领始于1000多年前，该项目产生了过去2000年的变化记录，它提供了一个独特的视角，以放大与NAO相关的气候变化对脆弱景观的影响，例如冰岛和许多其他以前的冰川地区。通过评估流域对反复气候扰动的响应，如NAO，在人类土地利用之前和之后，以及在保护管理之前和之后，这项工作提供了关于保护工作在减轻人类对气候变化的影响方面的有用性的见解。该项目还为研究机会相对有限的机构（普利茅斯州立大学和塞勒姆州立学院）的本科生和研究生提供了急需的研究、教育、实地和实验室培训机会，提供了与三个一级研究机构（美国大学）的接触和参与。美国缅因州科罗拉多州和美国明尼苏达州）。学生参与项目的各个层面，并学习通常在研究型机构中实践的最先进的跨学科方法。它为学生创造了机会，以口头和书面出版物的研究成果相关的复杂思想进行交流。参与该项目的五名高级研究人员还接受了最先进的跨学科方法和应用方面的培训，这提高了他们的教学和研究能力。这项工作涉及大量使用LacCore和大湖观测站的国家实验室设施，并结合3个新英格兰校区的努力，利用现有设施和人力资源，建设新的区域能力。