The Carbon Balance of Arctic River Deltas: Tundra Fire as an Agent of System Change

2015年夏天对北极地区来说是非同寻常的一年，包括育空-库斯库温三角洲，这预示着苔原和北方地区的火灾将更加常见。值得注意的是，2015年YK三角洲的燃烧面积超过了1940-2014年的总和。YK三角洲在火灾后第一年的反应将为三角洲在冻土带、水生和海洋系统以及对大气的碳储存和运输方面的长期变化奠定基础。量化碳输出和了解生态系统对火灾的直接反应至关重要，因为长期恢复在很大程度上取决于短期反应。本研究将解决的一个主要问题是，火灾如何影响三角洲生态系统季节性和火灾后第一年的碳运输量和形式。最终，这些结果将为三角洲碳库的脆弱性和命运的长期轨迹提供信息。这项研究将大大提高我们对火灾在北极河流三角洲现代和古代碳损失中的作用的理解，这些河流三角洲占北极地区碳总量的10%。美国巨大的永久冻土碳储量。这笔资金将允许项目科学家与阿拉斯加原住民教师和学生在伯特利部落学院进行以stem为重点的教师培训项目，这将为教师提供开展气候变化和北极系统科学研究的经验，并有机会开发以气候变化为重点的课程，以及育空河三角洲生态系统火灾和其他变化带来的反馈。该项目还将改善明尼苏达州中部一所小型本科学院的北极研究和教学基础设施。北极河流三角洲是碳储存的热点地区，占据了泛北极流域的1%，但却包含了北极永久冻土中储存的10%的碳。它们也是相互联系的陆地和水生生态系统的异质嵌合体，易受陆地、河流和海洋系统变化的影响。北极河流三角洲储存的碳的脆弱性是一个主要的未知因素，这一点至关重要，因为气候变暖和火灾频率的增加可能使这些碳容易运输到水生和海洋系统以及大气中。本提案的目标是研究火灾对育空-库斯库温三角洲碳储量的直接影响以及三角洲陆地和水生成分之间的交换。通过扩展，这项工作将对北极系统中三角洲的碳平衡在未来几十年将如何随着变暖的持续和火灾频率的增加而变化产生关键的见解。

The summer of 2015 was an extraordinary year for fire in the Arctic, including in the Yukon-Kuskokwim Delta, presaging a future where tundra and boreal fire is far more common. Remarkably, the area burned in the YK Delta in 2015 exceeds the total area burned from 1940-2014 combined. The response of the YK Delta in the first year post-fire will set the stage for longer-term changes in delta carbon storage and transport among tundra, aquatic and marine systems, and to the atmosphere. Quantifying carbon export and understanding the immediate ecosystem response to fire is critical because long-term recovery is, to a considerable degree, dependent on short-term responses. A major question that this research will address is how fire influences the amount and form of carbon transported from delta ecosystems seasonally and in the first year following fire. Ultimately, these results will inform long-term trajectories of the vulnerability and fate of delta carbon pools. This research will significantly improve our understanding of the role of fire in the loss of both modern and ancient carbon from arctic river deltas, which contain 10% of the Arctic?s massive permafrost carbon store. This funding will allow project scientists to engage with Alaska Native faculty and students in STEM-focused teacher training programs at the tribal college in Bethel, which will provide teachers with experience conducting research on climate change and arctic system science and the opportunity to develop curriculum focused on climate change and the feedbacks that result from fire and other changes in ecosystems in the Yukon River Delta. This project will also improve the infrastructure for arctic research and teaching at a small Undergraduate Institution in central Minnesota. ]Arctic river deltas are hotspots for carbon storage, occupying 1% of the pan-Arctic watershed but containing 10% of carbon stored in arctic permafrost. They are also heterogeneous mosaics of linked terrestrial and aquatic ecosystems, and are susceptible to changes in land, river, and marine systems. The vulnerability of carbon stored in arctic river deltas is a major unknown and is critically important as climate warming and increasing fire frequency may make this carbon vulnerable to transport to aquatic and marine systems and to the atmosphere. The goal of this proposal is to examine the immediate effects of fire on carbon storage in the Yukon-Kuskokwim Delta and exchange between terrestrial and aquatic components of the Delta. By extension this work will yield critical insights into how the carbon balance of deltas in the arctic system will change over the coming decades as warming continues and fire frequency increases.