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，缓慢的有机物分解导致了永久冻土中大量有机碳的积累。然而，虽然持续的气候变暖和永久冻土融化预计会增加植物生产力（二氧化碳吸收），但持续的变暖也预计会削弱先前对分解（二氧化碳排放）的限制。这些变化对北极的净影响是什么？由于大多数观测都是在较短的生长季节进行的，因此对美国的碳收支和全球气候系统了解甚少，而在这个季节，根和根际呼吸作用主导了二氧化碳的排放。该项目将重点开发一种新技术，用于持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）陷阱将是坚固的，小的，轻的，低成本的，并且需要很少的动力（电池）的方式低功率。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的冬季和平季，并且需要数周（3周/样本），从而整合扩散和偶发性排放。外展活动将加强加州大学欧文分校现有的由美国国家科学基金会支持的K-12培训项目，该项目旨在提高贫困人口在STEM领域的参与度。调查人员将与中学生在实验室参观和活动期间？大学的一天？-体验和课堂参观。该项目还将培养一名研究生，并（通过国际暑期课程）帮助研究人员在生态学和地球系统科学中使用14C分析。研究人员将开发并部署一种新的系统，在几周内连续捕获北极苔原土壤排放的二氧化碳，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的基于罐的系统可能相对较大，运输成本高，并且需要线路电力。该项目将开发和部署一种新型系统，在几周内持续捕获北极冻土带土壤排放的二氧化碳，用于放射性碳（14C）分析。这种连续收集系统有可能改变碳循环研究。这样的装置将避免向北极运送大型储罐和对线路电力的需求。此外，这种设备相对便宜且重量轻，因此可以进行高空间分辨率的监测。然而，这些新的陷阱从未在北极进行过测试，那里的环境条件可能很恶劣，尤其是在冬天。因此，这项工作的重点是在阿拉斯加北坡的图里克湖长期生态站，通过多个冬季来开发、强化和测试这些设备。如果成功，该装置将提供第一个全年、准连续的湿润酸性tussock冻土带土壤呼吸14CO2数据集，这是阿拉斯加北极地区主要的冻土带类型，全球占冻土带陆地面积的20%以上。此外，这项研究将为在整个北极类似恶劣环境下工作的其他实验小组指明方向。

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.