Winter carbon losses in wetland ecosystem under current and future climates

包括北极和加拿大北方地区在内的高纬度寒冷地区的变暖速度是地球其他地区的两倍多，其中最大的变暖发生在冬季。由于微生物呼吸是二氧化碳（CO2）排放的主要过程，即使在零度以下的温度下，微生物呼吸也会随着变暖而增加，因此冬季是碳循环的关键时期。因此，随着气候变暖，非生长季节（NGS;秋季、冬季、春季）的CO2排放量预计会增加。然而，目前对寒区生态系统NGS CO2排放量的估计存在很大的不确定性。加拿大的亚北极湿地和永久冻土泥炭地拥有大量的碳储存，在未来气候变暖的情况下很容易损失。因此，了解NGS期间控制温室气体排放的过程的因素对于预测这些可再生碳储量的命运以及制定气候适应和缓解战略至关重要。以这些关键生态系统为重点，我们汇集了来自各大学多个学科的加拿大领导人与联邦政府科学家和政策制定者，以确定NGS碳循环的驱动因素，开发基于过程的环境模型，并估计二氧化碳排放量。在此过程中，我们将解决NGS排放的知识差距，提供数据和工具，以评估冬季变暖缓解对控制泛加拿大湿地生态系统碳损失的影响。通过历史数据分析、实验室实验和建模相结合，拟议的研究将侧重于1）确定驱动微生物NGS碳循环的水文和气候因素; 2）将获得的信息和数据整合到描述控制NGS排放的基本过程的模型中，以纳入加拿大森林部门的碳预算模型（CBM-CFS）。这将提高我们跟踪和预测寒冷地区湿地生态系统碳通量的能力，并提出改进的、基于证据的建议，以估计冬季碳损失和评估减缓战略。

High latitude cold regions, including Arctic and northern areas of Canada, are warming more than twice as fastas the rest of the planet, with the greatest warming occurring during the winter. Given that a major processresponsible for carbon dioxide (CO2) emissions, microbial respiration, increases with warming even atsub-zero temperatures, winter is a critical period for carbon cycling. Consequently, CO2 emissions during thenon-growing season (NGS; fall, winter, spring) are expected to increase as the climate warms. However, thereis large uncertainty in estimates of current NGS CO2 emissions from cold region ecosystems. Canada'stemperate to subarctic wetlands and permafrost peatlands hold large stores of carbon which are susceptible toloss under future climate warming scenarios. Therefore, understanding the factors which regulate the processescontrolling greenhouse gas emissions during the NGS is critical for predicting the fate of these vulnerablecarbon stocks and for creating climate adaptation and mitigation strategies. With a focus on these criticalecosystems, we bring together Canadian leaders from multiple disciplines from across universities with federalgovernment scientists and policy makers to determine the drivers of NGS carbon cycling, developprocess-based environmental models, and estimate CO2 emissions. In doing so, we will address the knowledgegaps on NGS emissions to provide data and tools to evaluate the impact of winter warming mitigation incontrolling carbon losses from pan-Canadian wetland ecosystems. Through a combination of historical datasynthesis, laboratory experiments and modelling, the proposed research will focus on 1) determining thehydrological and climatic factors driving microbial NGS carbon cycling; and 2) integrating the information anddata gained into models describing the underlying processes controlling NGS emissions for incorporation intothe Carbon Budget Model of the Canadian Forest Sector (CBM-CFS). This will advance our ability to trackand predict carbon fluxes in cold regions wetland ecosystems and make improved, evidence-basedrecommendations to estimate winter carbon losses and evaluate mitigation strategies.