Collaborative Research: EAGER: Quantifying the Sources of Arctic Tundra-Respired CO2 Year-Round via Continuous in Situ Sampling of 14CO2

自更新世以来，缓慢的有机质分解导致了永冻土中大量有机碳的积累。然而，尽管正在进行的气候变暖和永久冻土融化预计将提高植物生产力(二氧化碳吸收)，但持续变暖也预计将削弱先前对分解(二氧化碳排放)的限制。这些变化对北极的净影响是什么？S碳收支和全球气候系统的了解很少，因为大多数观察是在短暂的生长季进行的，那时根和根际呼吸是二氧化碳排放的主要部分。该项目的重点将是开发一种新技术，用于连续收集北极冻土带土壤排放的二氧化碳。这种用于测量土壤呼吸二氧化碳的被动扩散筛(沸石)捕集器将坚固耐用、体积小、重量轻、成本低，并且需要很少的电力(电池)低功率。它有可能改变我们对北极碳循环的理解，因为它允许全年收集二氧化碳，包括在通常无法进入地点的冬季和肩季，以及数周(3周/样本)，从而将扩散排放和间歇性排放结合在一起。外展活动将加强加州大学欧文分校现有的由国家科学基金会支持的K-12培训计划，旨在增加贫困人口在STEM领域的参与。调查人员将让中学生在大学一天的时间里进行实验室之旅和活动--体验和参观课堂。该项目还将培训一名研究生，并帮助教育研究人员(通过国际暑期课程)在生态学和地球系统科学中使用14C分析。研究人员将开发和部署一种新的系统，在几周内连续捕获北极冻土释放的二氧化碳，用于放射性碳(14C)分析。然而，用于测量土壤呼吸二氧化碳的典型罐式系统可能相对较大，运输成本较高，并且需要线路供电。该项目将开发和部署一种新的系统，在几周内连续捕获从北极冻土带土壤中排放的二氧化碳，用于放射性碳(14C)分析。这种连续收集系统具有改变碳循环研究的潜力。这样的装置还将消除向北极运送大罐的需要，也不需要线路供电。此外，这种设备相对便宜和轻便，因此允许进行高空间分辨率的监测。然而，这些新的诱捕器从未在北极进行过测试，那里的环境条件可能很恶劣，特别是在冬天。因此，这项工作的重点是在阿拉斯加北坡的图利克湖长期生态站通过几个冬季来开发、硬化和测试这种设备。如果成功，该设备将提供第一个全年、准连续的数据集，关于潮湿的酸性苔原土壤呼吸的14CO2，这是北极阿拉斯加的主要冻土带类型，占全球冻土带陆地表面的20%以上。此外，这项研究将为其他在北极类似恶劣环境中工作的实验小组指明方向。

Since the Pleistocene, slow organic matter decomposition has led to the accumulation of vast amounts of organic carbon in permafrost. However, while ongoing climate warming and permafrost thaw are expected to increase plant productivity (CO2 uptake), continued warming is also expected to weaken prior constraints on decomposition (CO2 emissions). The net effect of these changes on the Arctic?s carbon budget and the global climate system are poorly understood, as most observations have been made during the short growing season, when root and rhizosphere respiration dominate CO2 emissions. This project will focus on the development of a new technology for the continuous collection of CO2 emitted from arctic tundra soils. This passive diffusive sieve (zeolite) trap for measuring soil respired CO2 will be rugged, small, lightweight, low-cost, and require little in the way of power (batteries) low power. It has the potential to transform our understanding of carbon cycling in the Arctic, as it allows for the year-round CO2 collection, including during the winter and shoulder seasons when sites are often inaccessible, and over multiple weeks (3 weeks/sample), thus integrating both diffusive and episodic emissions. Outreach activities will strengthen the existing NSF-supported K-12 training programs at UC Irvine that are aimed to increase the participation of underprivileged populations in the STEM fields. THE Investigators will engage middle school students with lab tours and activities during a ?Day at College?-experience and class room visits. The project will also train a graduate student, and contribute to educating researchers (via an international summer course) in the use of 14C analysis in Ecology and Earth System Science.The investigators will develop and deploy a novel system to continuously trap CO2 emitted from arctic tundra soils over several weeks for radiocarbon (14C) analysis. However, typical canister-based systems for measuring soil respired CO2, can be relatively large, expensive to ship, and require line power. This project will develop and deploy a novel system to continuously trap CO2 emitted from Arctic tundra soils over several weeks for radiocarbon (14C) analysis. This continuous collection system has the potential to transform carbon cycle research. Such devices would obviate the need for shipping large canisters to the Arctic as well and the need for line power. Moreover, such devices are relatively inexpensive and lightweight, and therefore, permit for high spatial resolution monitoring. These new traps, however, have never been tested in the Arctic, where the environmental conditions can be harsh, especially in winter. Thus the focus of this work is to develop, harden, and test such devices through a number of winter seasons at the Toolik Lake Long Term Ecological Station, on the north slope of Alaska. If successful, this device will provide the first year-round, quasi-continuous dataset on soil-respired 14CO2 in moist acidic tussock tundra, which is the dominant tundra type of arctic Alaska and globally accounts for over 20% of the tundra land surface. Moreover, this research will point the way for other experimental groups working in similar harsh environments throughout the Arctic.