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，有机质的缓慢分解导致了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将增加植物生产力（二氧化碳吸收），但持续变暖预计也会削弱先前对分解的限制（二氧化碳排放）。这些变化对北极的净影响是什么？人们对植物的碳收支和全球气候系统知之甚少，因为大多数观测都是在短暂的生长季节进行的，此时根和根际呼吸作用主导了CO2排放。 该项目将侧重于开发一种新技术，用于连续收集北极苔原土壤排放的二氧化碳。用于测量土壤呼吸CO2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，并且需要很少的电源（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，包括在冬季和平季，当网站通常无法访问时，并在多个星期（3周/样本），从而整合了扩散和偶发排放。 外展活动将加强现有的NSF支持的K-12培训计划在加州大学欧文分校，旨在提高贫困人口在干领域的参与。调查人员将在一个实验期间让中学生参加实验室图尔斯和活动。在大学的一天？体验和教室参观。该项目还将培训一名研究生，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14 C分析。研究人员将开发和部署一种新型系统，连续捕获北极苔原土壤在数周内排放的CO2，用于放射性碳（14 C）分析。 然而，用于测量土壤呼吸CO2的典型的基于罐的系统可能相对较大，运输昂贵，并且需要线路功率。 该项目将开发和部署一种新的系统，在数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（14 C）分析。 这种连续收集系统有可能改变碳循环研究。 这样的设备将满足将大型罐运输到北极的需要以及对线路电力的需要。 此外，这种装置相对便宜且重量轻，因此允许高空间分辨率监测。 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，尤其是在冬季。 因此，这项工作的重点是通过在阿拉斯加北坡的图里克湖长期生态站的一些冬季开发，硬化和测试这些设备。 如果成功的话，该设备将提供第一个全年的，准连续的数据集土壤呼吸14二氧化碳在潮湿的酸性草丛苔原，这是主要的苔原类型的北极阿拉斯加和全球占苔原陆地表面的20%以上。 此外，这项研究将为在整个北极地区类似恶劣环境中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.