LTREB Renewal: The reorganization and resynchronization of biogeochemical cycles after an unprecedented tundra fire

历史上，北极苔原地区很少发生火灾，但预计在未来变暖的世界中，火灾的严重程度和频率都会增加。该生物群系中火灾的罕见性使得测量、理解和预测火灾对物种多样性和生态系统碳循环等重要生态系统服务的影响具有挑战性。此外，火灾的影响持续很长时间——几年到几十年——通过改变对长期生态系统恢复很重要的关键生物地球化学循环。由于火灾严重程度会显著降低土壤养分有效性，因此假设生态系统的恢复取决于燃烧严重程度和火灾后的土壤资源。这个项目延续了一个为期十年的项目，研究火灾对阿拉斯加冻土带生态系统陆地碳循环的影响。该研究结合了长期生态观测、营养添加试验和生态系统模型改进。为本科生和研究生提供培训和工作相关技能。将出版一本儿童读物，并在YouTube上发布视频。大量关于生态系统过程的数据正在被提供给公共数据库。本研究将从2007年阿拉斯加北坡前所未有的阿纳克图伍克河火灾中获取并综合生态系统功能的多年记录（2008-2026）。涡旋相关通量和生物量收获将测量整个燃烧严重程度梯度（严重、中度和未燃烧冻土带）的生态系统碳通量和储量的时间变化，而在严重和未燃烧冻土带地点进行的养分施肥试验将确定养分有效性对生态系统恢复速度的作用。这些记录将为耦合的生物地球化学模型（即多元素限制[MEL]模型）提供信息，以改进火灾对北极生态系统碳循环的长期影响的预测。MEL模型的发展将为科学家、土地管理者和政策制定者量化这一快速变化地区未来火灾的影响提供有力的工具。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Fire has been historically rare in the Arctic tundra, but is projected to increase in severity and frequency in a future warmer world. The rarity of fires in this biome has made it challenging to measure, understand, and predict the consequences of fire on important ecosystem services such as species diversity and ecosystem carbon cycling. Furthermore, the impacts of fire last a long time-- years to decades-- by altering critical biogeochemical cycles that are important for long term ecosystem recovery. Since fire severity can dramatically reduce soil nutrient availability, it is hypothesized that ecosystem recovery is dependent on both burn severity and post-fire soil resources. This project continues a ten-year project studying the effects of fire on terrestrial carbon cycling in Alaskan tundra ecosystems. The research combines long-term ecological observations, a nutrient addition experiment, and improvement of an ecosystem model. Training and workforce relevant skills for both undergraduate students and graduate students are being provided. A children’s book will be published to reach the general public, as well as a YouTube video. A large amount of data about ecosystem processes is being contributed to public databases.This research will acquire and synthesize a multi-decadal record (2008-2026) of ecosystem function from the unprecedented 2007 Anaktuvuk River fire on the North Slope of Alaska. Eddy covariance fluxes and biomass harvests will measure temporal changes in ecosystem carbon fluxes and stocks across a burn severity gradient (Severe-, Moderate-, and Un-burned tundra), while nutrient fertilization experiments at the Severe- and Un-burned tundra sites will determine the role of nutrient availability on the rate of ecosystem recovery. These records will inform a coupled biogeochemical model (i.e. the Multiple Element Limitation [MEL] model) to improve predictions of the long term impacts of fire on Arctic ecosystem carbon cycling. The development of the MEL model will provide a powerful tool for scientists, land managers, and policy makers to quantify the future impacts of fire in this rapidly-changing region.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.