LTER: The Role of Climate Variability in Controlling Arctic Ecosystem Function

北极变暖的速度比地球上其他地方更快。先前冻土的融化将通过改变碳排放而对社会产生影响。以前的大多数研究都集中在北极生态系统如何应对平均变暖趋势。然而，关于环境条件在平均变暖趋势内的变异性的研究很少。北极长期生态研究地点(ARC-LTER)社区发现，冻土带生态系统在一系列时间尺度上对环境波动做出强烈反应。ARC-LTER将继续产生长期数据，并进行模拟模拟，以检验环境变异性对关键生态系统功能的作用。这次更新的主要活动将扩大我们的理解，重点是气候变化如何影响陆地生产和有机物质的分解，以及这些过程如何结合在一起影响湖泊和溪流中的二氧化碳产生。因此，该项目将有助于理解平均气候、气候变异性和扰动的趋势如何相互作用来控制北极生态系统的结构和功能。该项目将产生更广泛的影响，如培训年轻的研究人员，通过地球营计划让K-12教师参与研究，校园活动和教师的研究经验。与利益相关者的接触将包括向阿拉斯加州、北坡行政区以及监督环境和自然资源项目的美国政府机构进行简报。ARC-LTER还将与北极环境变化研究计划合作，与土著专家共同产生知识，用于决策。2023-2029年ARC-LTER项目将确定气候趋势的同时和环境条件变化的变化如何结合在一起影响北极生态系统。该项目将检验这样一种假设，即环境条件的变化比气候的平均长期趋势更能驱动北极的变化。该项目将研究生态系统的“开放性”和“关联性”与野火和气候变化等干扰因素之间的关系。这项研究将包括在亚肯色州图利克湖附近维持正在进行的和开展与长期监测、实验和数值模拟工作有关的新活动。该项目将解决三个主要问题，这些问题将整合陆地-水生连续体的研究：问题1：气候变化如何影响北极生态系统的开放性和连通性？这项研究将集中在沿现有营养梯度的湿润酸性冻土带、变暖的地块和附近的赤杨林中的植被和生物地球化学循环。问题2：气候变化如何影响主要消费者及其对生态系统的影响？研究活动将集中在气候变化如何影响消费者群体的组成，它们对生态系统的影响，以及微生物群体的基因组潜力和新陈代谢。问题3：气候变异性如何影响陆地-水生连续体的碳动态？该项目将研究连续体中碳生物地球化学的动态如何受到环境变异性的影响。总之，这些问题的答案将提高我们对环境长期和短期变化如何塑造生态系统功能的理解。这个长期生态研究地点得到了环境生物学部门和极地项目办公室的支持。该奖项反映了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。

The Arctic is warming more rapidly than the rest of the planet. Thawing of previously frozen soils will have consequences for society through alteration of carbon emissions. Most previous research has focused on how Arctic ecosystems respond to average warming trends. There is however very little research on variability of environmental conditions within that average warming trend. The Arctic Long-Term Ecological Research site (ARC-LTER) community has found that tundra ecosystems respond strongly to fluctuations in environment on a range of time scales. ARC-LTER will continue to produce long-term data and perform modeling simulations that examine the role of that environmental variability on critical ecosystem functions. The main activities in this renewal will expand our understanding by focusing on how climate variability affects the terrestrial production and breakdown of organic matter and how those processes combine to affect CO2 production in lakes and streams. The project will therefore contribute understanding of how trends in mean climate, climate variability, and disturbances all interact to control arctic ecosystem structure and function. The project will have many broader impacts such as training of young investigators, engagement of K-12 teachers in research via the Earth Camp program, schoolyard activities and research experiences for teachers. Outreach to stakeholders will include briefings to Alaska State, North Slope Borough, and US government agencies overseeing environmental and natural resource programs. ARC-LTER will also work with the Study of Environmental Arctic Change program on co-production of knowledge with Indigenous experts for use in decision making.The 2023-2029 ARC-LTER project will determine how concurrence of climate trends and altered variability of environmental conditions combine to affect arctic ecosystems. The project will test the hypothesis that variability in environmental conditions is a stronger driver of change in the Arctic than are the average long-term trends in climate. The project will examine how ‘openness’ and ‘connectedness’ of ecosystems relate to disturbances such as wildfire and climate change. This research will include the maintenance of ongoing and development of new activities associated with long-term monitoring, experiments and numerical modeling work in the vicinity of Toolik Lake, AK. The project will address three main questions which will integrate research along the terrestrial-aquatic continuum: Question 1: How does climate variability affect the openness and connectivity of arctic ecosystems? This research will focus on vegetation and biogeochemical cycles in moist acidic tundra along an existing nutrient gradient, within warming plots, and in nearby Alder stands. Question 2: How does climate variability affect key consumers and their influence on ecosystems? The research activities will focus on how climate variability affects the composition of consumer communities, their influence on ecosystems, and the genomic potential and metabolism of microbial communities. Question 3: How does climate variability affect carbon dynamics along the terrestrial-aquatic continuum? The project will study how the dynamics of carbon biogeochemistry along the continuum are affected by environmental variability. Together, the answers to these questions will improve our understanding on how long and short-term changes in environment shape ecosystem function.This Long Term Ecological Research site is supported by The Division of Environmental Biology and the Office of Polar Programs.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.