Collaborative Research: Predicting Micro to Macro-scale Hot-spot and Hot-moment dynamics in Arctic Tundra Ecosystems

北极地区快速的气候变暖正在融化冻土，也就是永久冻土，这不仅重塑了地表地形，而且增加了向大气中释放的温室气体。由于北极景观变化的速度，以及永久冻土中大量的碳库，提高对植物和微生物之间关键相互作用及其对温室气体释放影响的认识，对于预测北极土壤融化将如何促进全球气候变化至关重要。该项目的总体目标是确定驱动热点和热时刻碳动力学的微观尺度机制，以改进宏观尺度碳平衡的预测。我们假设，退化的富含营养的永久冻土时空分布的改变已经并将从根本上改变北方冻土带生态系统的结构和功能，从微生物到景观。这个多尺度跨学科项目将改变我们对多年冻土生态系统中控制过去和未来碳循环动态的基本植物-土壤-微生物相互作用的认识，同时推进对多年冻土融化在空间（即地块到景观）和时间（即季节到年代际）上的关键生物地球化学后果的认识。利用低、高精度地面和空中通量观测相结合的方法，对热点和热时刻碳动态的时空机制进行表征，以确定二氧化碳（CO2）和甲烷（CH4）热点的位置和大小。地面和遥感观测将确定对观测到的热点和通量空间分布的控制，植物、微生物和地貌的时空分析，加上永久冻土退化的时间，将推断热矩的存在，而孵化实验将阐明在阿拉斯加北部北极沿海平原各地点驱动热矩的机制。因此，拟议的研究将为下一代机制和基于过程的模型提供基础，以代表新北极的新扰动制度。这些研究工作将得到阿拉斯加本地高中生参与北极扰动生态学的日益增长的合作网络的称赞。学生们将使用无人机测量他们的环境，并在整个校园和更广泛的科学界分享结果。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。

Rapid climate warming in the Arctic is thawing frozen soils, also known as permafrost, which is not only reshaping surface topography but also increasing the release of greenhouse gases to the atmosphere. Due to the speed in which Arctic landscapes are changing, and the massive carbon pools locked in permafrost, improving knowledge of the key interactions between plants and micro-organisms and their impacts on greenhouse gas release is essential for predicting how thawing Arctic soils will contribute to global climate change.The overarching objective of this project is to determine the micro-scale mechanisms driving hot-spot and hot-moment carbon dynamics, for improving predictions of macro-scale carbon balance. We hypothesize that the altered spatiotemporal distribution of degrading nutrient-rich permafrost has and will fundamentally alter the structure and function of northern tundra ecosystems, from microbes to landscapes. This multi-scale interdisciplinary project will transform our knowledge of fundamental plant-soil-microbial interactions that govern past and projected carbon cycle dynamics in permafrost ecosystems, while advancing knowledge of the key biogeochemical consequences of permafrost thaw over space (i.e., plot to landscape) and time (i.e., seasonal to decadal). The spatiotemporal mechanisms of hot-spots and hot-moment carbon dynamics will be characterized using a combination of low and high-precision ground and airborne flux observations to determine the location and assess the magnitude of carbon dioxide (CO2) and methane (CH4) hot-spots. Ground and remote sensing observations will determine the controls on the observed spatial distribution of hot-spots and fluxes, space-for-time analyses of plants, microbes, and landforms, coupled with the timing of permafrost degradation will infer the existence of hot-moments, while incubation experiments will illuminate the mechanisms driving hot-moments across sites across the Arctic Coastal Plain of northern Alaska. The proposed research will therefore provide the foundation for next-generation mechanistic and process-based models to represent novel disturbance regimes in the new Arctic. These research efforts will be complimented by a growing collaborative network of Alaskan native high-school student involvement in Arctic disturbance ecology. Students will use drones to measure their environment and share results across campuses and with the broader scientific community.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.