Dissertation Research: Controls on Methane Flux from Arctic Tundra

高纬度生态系统是对气候变化加速最敏感的地区之一，其中一些地区的气温上升速度最快，水文模式也发生了变化。锁定在北方土壤中的丰富碳储量越来越容易以甲烷的形式释放到大气中。甲烷是一种强大的温室气体，随着大气浓度的增加，它有可能进一步加快变暖的速度。影响天然湿地生态系统产生和释放甲烷量的两个主要环境因素是：(1)土壤的湿润程度，(2)土壤的温暖程度，但人们对这些因素在季节过渡时期（如春末土壤解冻和积雪减少）如何相互作用知之甚少。本项目利用便携式温室气体分析仪测量芬兰北部沼泽在2013年春季过渡期和夏季生长期的甲烷气体排放量，利用融雪和土壤操纵实验确定这些变量对甲烷排放率的影响。正是因为高纬度地区的气候变化速度比地球上其他地区快，所以高纬度地区的甲烷研究对我们了解未来的气候动态至关重要。这项研究不仅有助于提高对北部湿地甲烷循环的科学认识，而且有助于改进全球气候模型，为国际气候变化决策提供信息。此外，这项研究认识到气候变化不仅仅是一个国家问题，并促进了与作者的跨国比较。正在进行的阿拉斯加湿地研究实地工作将包括一名PolarTREC志愿者的参与，他是一名美国中学科学教师，他将提供多种外联途径，向年轻的美国人宣传这项研究。将在芬兰和美国进行额外的外展和实地教学机会。

High-latitude ecosystems are among the most sensitive to accelerating climate change, with some of the highest rates of temperature increase and altered hydrological patterns. The rich carbon reserves locked in northern soils are increasingly prone to being released into the atmosphere as methane, a powerful greenhouse gas that, as atmospheric concentrations increase, is liable to further increase the speed of warming. The two major environmental factors that affect the amount of methane being made and released from natural wetland ecosystems are (1) how wet the soil is, and (2) how warm the soil is, but little is known about how these factors interact during seasonal transition periods like late spring, when soils thaw and lose snow cover. This project uses a portable greenhouse gas analyzer to measure methane gas emissions from a northern Finnish mire during the 2013 spring transition period and summer growing season, using snow-melting and soil manipulation experiments to determine the influence of these variables on methane emission rates.Precisely because they are experiencing climate changes at faster rates than the rest of the planet, methane studies in high-latitude systems are critical to our understanding of future climate dynamics. This research will contribute not only to scientific knowledge of methane cycling in northern wetlands, but also to improving global climate models that inform international climate change policymaking. Moreover, this research recognizes that climate change is not merely a national issue, and facilitates trans-national comparisons with the authors? ongoing study of Alaskan wetlands. The field work will include the participation of a PolarTREC volunteer, an American middle school science teacher, which will provide multiple outreach avenues for informing young Americans about this research. Additional outreach and field-based teaching opportunities will be conducted, both in Finland and America.