Collaborative Research: Shrub Impacts on Nitrogen Inputs and Turnover in the Arctic, and the Potential Feedbacks to Vegetation and Climate Change

合作研究：灌木对北极氮输入和周转的影响，以及对植被和气候变化的潜在反馈

基本信息

批准号：
1556481
负责人：
Marion Bret-Harte
金额：
$ 75.29万
依托单位：
University of Alaska Fairbanks Campus
依托单位国家：
美国
项目类别：
Standard Grant
财政年份：
2016
资助国家：
美国
起止时间：
2016-09-01 至 2022-08-31
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=1556481&HistoricalAwards=false
关键词：
Collaborative Research Shrub Impacts Nitrogen

项目摘要

Ecosystems develop and change through interactions between living organisms and their physical environment. A shift in vegetation is one of the most important changes an ecosystem can experience, because it can alter exchanges of energy (originating from sunlight), water, and elements such as carbon and nitrogen, among air, plants, and soil. In the Arctic, a widespread shift from tundra to shrub-dominated vegetation appears to be occurring. This research project will discern whether, through complex interactions, this transition to shrublands in the Arctic is likely to result in the release of more carbon into the air (as either carbon dioxide or methane, which are both greenhouse gases). Vast amounts of carbon are stored in Arctic and northern soils, so reduced carbon storage in the Arctic may affect weather and climate in other parts of the world. This project will assess the contributions of different shrub feedbacks to carbon (C) and nitrogen (N) cycling. Snow depth will be manipulated with existing snow fences across a natural gradient of shrub density and height, and a new snowfence experiment will be established in alders. Shrub-induced changes in soil C over the longer term in one ecosystem will be examined in an 18-year-old species removal experiment. Shrub growth, primary production, and biomass will be measured. Long-term effects of added snow on ecosystem N partitioning and shrub N uptake will be measured in a 15N tracer experiment. N fixation will be measured in alder populations and moss communities associated with shrubs. The relative strengths of different shrub feedbacks to N availability and uptake by vegetation will be evaluated. This project will improve prediction of the consequences of shrub expansion in the Arctic, and its potential impacts on regional and global climate. Results will contribute to training of graduate and undergraduate students, to public outreach and training of K-12 teachers and students, and to development of a web-based resource for education.

生态系统通过生物体与其物理环境之间的相互作用发展和变化。植被的转变是生态系统可以体验到的最重要的变化之一，因为它可以改变能量交换（起源于阳光），水以及碳和氮等元素，在空气，植物和土壤中。在北极，从苔原转向灌木主导的植被似乎正在发生。该研究项目将通过复杂的相互作用来辨别这种向北极中灌木丛的过渡是否可能导致更多的碳释放到空气中（例如二氧化碳或甲烷，都是温室气体）。大量的碳存储在北极和北部土壤中，因此北极碳储存的减少可能会影响世界其他地区的天气和气候。该项目将评估不同灌木反馈对碳（C）和氮（N）循环的贡献。积雪深度将通过自然的灌木密度和高度的天然梯度进行操纵，并将在Alders中建立一个新的雪地实验。在一个18岁的物种去除实验中，将检查一个生态系统中灌木诱导的土壤C的变化。将测量灌木生长，初级生产和生物量。在15N示踪剂实验中，将测量降雪对生态系统N分区和灌木N摄取的长期影响。 n固定将在与灌木相关的al木种群和苔藓群落中进行测量。将评估不同灌木对N的相对强度，对N植被的n可用性和吸收的相对强度将得到评估。该项目将改善对北极灌木扩张后果的预测，及其对区域和全球气候的潜在影响。结果将有助于培训研究生和本科生，对K-12教师和学生的公共宣传和培训以及开发基于网络的教育资源。