EAR-PF: Biomass burning in the terrestrial Arctic during past warm periods: New insights from organic biomarkers in Lake El'gygytgyn (Siberia)

威廉·丹尼尔斯博士获得了NSF EAR博士后奖学金，在马萨诸塞大学阿默斯特分校开展研究和教育计划。这项研究将使用过去野火的地质记录来调查可能影响北极冻土带未来火灾流行的因素。野火在森林生态中发挥着重要作用，有助于全球碳循环，并会干扰人类活动。在北极，野火在历史上是罕见的，但随着气候变暖，野火的频率正在增加。考虑到现有的古火记录表明，寒冷干燥的气候比温暖潮湿的气候更有利于燃烧，最近的趋势令人惊讶。为了更好地了解气候和野火之间的联系，将对西伯利亚北极的古代湖泊沉积物进行分析，以寻找过去发生过野火的证据，这些时期跨越了广泛的气候条件。这项研究将检验永久冻土、干旱和植被会影响温度和冻土带野火之间的关系的想法。这项研究将与社区教育活动相结合，包括在马萨诸塞州和北极阿拉斯加为当地青年开设环境科学夏令营。拟议的研究将使用El‘gytgyn湖360万年的沉积物岩芯中的有机地球化学替代品，重建更新世-更新世期间北极生物量燃烧的变化。生物质燃烧的分子副产物左旋葡聚糖和多环芳烃将与上新世中期(3.02-3.26 Ma；未来全球气候的关键相似物)和超间冰期海洋同位素阶段31(1.06-1.08 Ma)独立获得的古气候重建进行比较。结果将提供上新世和更新世期间冰川-间冰期变异性的直接比较，以测试长期变暖下的永久冻土和植被变化是否会导致截然不同的火灾系统。这项研究将进一步开发和测试产生更多古火灾记录所需的分子火灾代理。这一裁决反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Dr. William Daniels has been granted an NSF EAR Postdoctoral Fellowship to carry out research and education plans at the University of Massachusetts Amherst. The research will use geologic records of past wildfires to investigate factors that might impact future fire prevalence in the Arctic tundra. Wildfires play an important role in forest ecology, contribute to the global carbon cycle, and can interfere with human activities. In the Arctic, wildfires are historically rare, but their frequency is increasing as climate warms. This recent trend is surprising given that existing paleofire records demonstrate that a cold and dry climate is more conducive to burning then a warm and wet climate. Ancient lake sediments from the Siberian Arctic will be analyzed for evidence of past wildfires during time periods that span a wide range of climatic conditions to better understand climate-wildfire linkages. The study will test the ideas that permafrost, aridity, and vegetation can influence the relationship between temperature and tundra wildfires. The research will be coupled with community education activities, including teaching environmental science camps for local youth in Massachusetts and Arctic Alaska.The proposed research will use organic geochemical proxies in a Lake El'gygytgyn sediment core covering 3.6 million years to reconstruct variations in Arctic biomass burning over the Plio-Pleistocene. Levoglucosan and polycyclic aromatic hydrocarbons, molecular byproducts of biomass burning, will be compared with independently-derived paleoclimate reconstructions during the mid-Pliocene Warm Period (3.02-3.26 Ma; a key analog for future global climate) and during the Superinterglacial Marine Isotope Stage 31 (1.06-1.08 Ma). Results will provide a direct comparison of glacial-interglacial variability during the Pliocene versus the Pleistocene to test if permafrost and vegetation shifts under prolonged warming could lead to profoundly different fire systematics. The study will further develop and test molecular fire proxies needed to generate additional paleofire records.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.