COLLABORATIVE RESEARCH: INVESTIGATING HYDROLOGY-DRIVEN MODELS FOR METHANE CYCLING IN NORTHERN PEATLANDS

目前泥炭地的碳循环将如何应对气候变暖的不确定性的一个主要因素是对游离相气体（FPG）的生产，储存和排放的不完全理解，这是一种以前未被充分认识的甲烷和二氧化碳排放到大气中的来源。越来越清楚的是，FPG的生产，储存和排放受水力作用力以及泥炭的机械特性的调节，即泥炭地中的碳和水循环密切相关。该项目的重点是现场规模的水文和水文地球物理研究，以进一步调查最近调用的“浅”与“深”泥炭模型的生产，存储和排放的FPG在北方泥炭地的重要性。该项目的具体目标包括[1]在泥炭地内的三个位置中的每一个位置，在至少六个月的时间段内量化甲烷储存和释放随深度的垂直变化，[2]确定驱动深层和浅层气体释放的水文强迫机制，[3]估计储存和释放的空间变化作为地下异质性的函数，以及[4]量化浅层与深层气体对来自北方泥炭地的甲烷排放的相对贡献。这项研究将通过将水文地质方法与对FPG生产、储存和排放敏感的新型腔室、地球物理和大地测量传感技术相结合来进行。野外现场是驯鹿沼泽，这是缅因州中部一个经过充分研究的多单元泥炭地复合体。将开发经验预测模型和简单的机理模型，以评估关键强迫机制对FPG排放的相对重要性。时间序列数据集的时频分析也将被用来提高对调节FPG生产、储存和释放的可能强迫成分的理解。这项研究将显着推进我们的理解水文控制FPG动态在北方泥炭地，泥炭地碳动态对气候变化的响应具有重要意义。北方泥炭地全球覆盖超过3.5亿公顷，包含约三分之一的陆地储存的碳。这种碳在应对持续气候变暖中的命运是高度不确定的。泥炭地也是大气甲烷的来源，甲烷是一种导致气候变暖的强效温室气体。这项研究将提供促进泥炭地甲烷循环的理解所需的基础科学知识，以及泥炭地水文学如何控制泥炭地甲烷向大气的排放。鉴于人们对气候变暖的环境和经济影响的关切，这项工作具有直接的社会意义。在这个项目中，洛伊斯·斯托克斯少数民族参与联盟的本科生将接触到三个机构之间的动手跨学科研究。此外，一个国际研究生团体将参加美国地球物理联盟会议上以学生为中心的关于北方泥炭地甲烷循环的会议。驯鹿沼泽附近的社区外联活动将通过每年利用奥罗诺沼泽木板路的图尔斯导游进行，该木板路在2009年接待了30 000多名游客。

Project AbstractA major contributor to the current uncertainty regarding how carbon cycling in peatlands will respond to climate warming is the incomplete understanding of the production, storage and emission of free phase gas (FPG), a previously under-appreciated source of methane and carbon dioxide emissions to the atmosphere. It is increasingly clear that FPG production, storage and emission are regulated by hydraulic forcing, as well as the mechanical properties of the peat, i.e. that the carbon and water cycles in a peatland are intimately connected. The focus of this project is field-scale hydrological and hydrogeophysical research to further investigate the importance of recently invoked "shallow" versus "deep" peat models for the production, storage and emission of FPG in northern peatlands. Specific objectives of the project include [1] quantifying vertical variations in storage and release of methane with depth over a minimum six month time period at each of three locations within a peatland, [2] determining the hydrological forcing mechanisms that drive releases from both deep and shallow gas, [3] estimating spatial variations in storage and release as a function of subsurface heterogeneity, and [4] quantifying relative contributions of shallow versus deep gas to methane emissions from a northern peatland. This research will be conducted by coupling hydrogeological methods with novel chamber, geophysical and geodetic sensing technologies sensitive to FPG production, storage and emissions. The field site is Caribou Bog, a well-studied multi-unit peatland complex in central Maine. Empirical predictive models and simple mechanistic models will be developed to assess the relative importance of key forcing mechanisms on FPG emissions. Time-frequency analysis of time-series datasets will also be employed to improve understanding of likely forcing components regulating production, storage and release of FPG. This research will significantly advance our understanding of hydrological controls on FPG dynamics in northern peatlands, with important implications for the response of peatland carbon dynamics to climate change.Northern peatlands globally cover more than 350 million ha and contain about one third of the terrestrially stored carbon. The fate of this carbon in response to continued climate warming is highly uncertain. Peatlands are also a source of atmospheric methane, a potent greenhouse gas that contributes to climate warming. This research will provide fundamental scientific knowledge needed to advance the understanding of the cycling of methane in peatlands, and how peatland hydrology controls the emission of methane from peatlands to the atmosphere. The work has direct societal relevance given the concerns about the environmental and economical affects of climate warming. In this project, Lois Stokes Alliance for Minority Participation undergraduate students will be exposed to a hands-on interdisciplinary research among three institutions. Furthermore, an international community of graduate students will participate in a student-focused session on methane cycling in northern peatlands at American Geophysical Union meetings. Community outreach in the vicinity of the Caribou Bog will occur via annual guided tours using the Orono Bog Boardwalk that served +30,000 visitors in 2009.