Mackenzie Delta thermogenic methane distribution, sources, drivers

麦肯齐三角洲产热甲烷分布、来源、驱动因素

• 批准号: RGPIN-2019-06006
• 负责人: Risk, Dave
• 金额: $ 2.62万
• 依托单位: St. Francis Xavier University
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=686692
• 关键词: Mackenzie; Delta; thermogenic; methane; distribution

Relative to surface biologic production of methane from soils, wetlands, and degrading permafrost, geologic seeps of methane are less well understood. We know that a large amount of methane is emitted from natural geologic seepage, venting oil and gas reservoirs or subsurface gas hydrates. Sporadic studies over the past two decades from provincial and federal scientists have identified huge natural seeps in the Mackenzie Delta. New aircraft studies suggest that geological seepage hotspots are a dominant control on landscape emissions, and that water body sources in the Mackenzie Delta were not the hotspots most global land surface models would expect. This leaves an uncomfortable friction between geologically-based estimates, and the findings of ecosystem scientists working elsewhere in the Arctic who conclude that warming temperatures and a deepening active layer drives increased methane production in large part from water bodies. Are geological emissions of methane in the Mackenzie Delta as prolific as new studies suggest? Could this be happening elsewhere, and do we need to revise our approach to studying Arctic methane?******My proposed research aims to understand geological methane distribution, sources, and drivers in the Mackenzie Delta. The research will focus on collecting data at landscape scales, since the debates are inherently about landscape distribution of sources. The research will involve a mixture of graduate students, undergraduates, and research associates, working alongside identified academic, government, and industry collaborators specialized in Mackenzie Delta methane and related issues (permafrost degradation, petroleum systems, geochemistry, measurement tools). To identify emission hotspots, we will apply landscape-scale (100s km) geochemical survey tools, in combination with satellite data. Within these areas we will undertake detailed investigations of sources and geochemistry, in an effort to understand local distribution, relative rates, and drivers of geological seeps and surface biogenic activity. This research is a natural extension of my experience in oil and gas tracer studies, cold-regions biogenic soil gas studies (including recent work in the Mackenzie Delta), and my keen interest in landscape-scale gas measurement methodologies, which for the first time will come together in a single project.******The results of this interdisciplinary work will be useful for atmospheric scientists, climate modelers, permafrost soil scientists, and geologists interested in petroleum systems and the long-term carbon cycle. Because there is also some focus on identifying biogenic methane, there is the possibility to link this work to permafrost thaw and decomposition of organics, methane from organic-loaded hydrologic systems, and landscape change (thaw-driven landslides, slumps). This research is also designed to connect with the NASA Arctic Boreal Vulnerability Experiment (ABoVE), in which I play a continuing role.**

相对于地表生物从土壤、湿地和退化的永久冻土中产生甲烷，甲烷的地质渗漏还不太清楚。 我们知道，大量的甲烷是从自然地质渗漏、石油和天然气储层或地下天然气水合物中排放出来的。 在过去的二十年里，省级和联邦科学家的零星研究发现了麦肯齐三角洲巨大的天然渗漏。新的飞机研究表明，地质渗漏热点是景观排放的主要控制因素，而麦肯齐三角洲的水体来源并不是大多数全球陆地表面模型所期望的热点。这使得基于地质的估计与在北极其他地方工作的生态系统科学家的发现之间存在令人不安的摩擦，他们得出结论认为，气温变暖和活动层加深导致甲烷产量增加，大部分来自水体。麦肯齐三角洲的甲烷地质排放是否像新研究所表明的那样多产？这种情况会发生在其他地方吗？我们是否需要修改我们研究北极甲烷的方法？我提议的研究旨在了解麦肯齐三角洲的地质甲烷分布、来源和驱动因素。 研究将侧重于收集景观尺度的数据，因为辩论本质上是关于源的景观分布。该研究将涉及研究生，本科生和研究助理的混合物，与确定的学术，政府和行业合作者一起工作，专门从事麦肯齐三角洲甲烷和相关问题（永久冻土退化，石油系统，地球化学，测量工具）。为了确定排放热点，我们将结合卫星数据，应用小尺度（100公里）地球化学调查工具。在这些地区，我们将进行详细的调查来源和地球化学，努力了解当地的分布，相对速率，以及地质渗漏和地表生物活动的驱动因素。这项研究是我在石油和天然气示踪剂研究，寒冷地区生物成因土壤气体研究（包括最近在麦肯齐三角洲的工作）方面经验的自然延伸，以及我对小规模气体测量方法的浓厚兴趣，这是第一次将在一个单一的项目中结合在一起。这项跨学科工作的结果将有助于大气科学家，气候建模者，永久冻土土壤科学家和对石油系统和长期碳循环感兴趣的地质学家。由于也有一些重点是识别生物甲烷，因此有可能将这项工作与永久冻土解冻和有机物分解，有机物负载水文系统的甲烷以及景观变化（解冻驱动的山体滑坡，滑塌）联系起来。 这项研究也旨在与美国宇航局北极地区脆弱性实验（ABoVE）联系起来，我在其中发挥了持续的作用。