A Mobile Instrument System for Measuring Dissolved Methane in Arctic Aquatic Environments

* 甲烷（CH 4）是一种重要的温室气体。虽然它在我们大气中的含量低于二氧化碳（CO2），但其每个分子的气候影响约为30倍。像二氧化碳一样，甲烷有自然和人为来源，两者的解释对于准确的气候预测非常重要。人们非常担心，随着我们的气候变暖，大量的天然甲烷可能会释放到大气中，加剧变暖。北极甲烷储量巨大，在永久冻土、海底沉积物以及海洋和淡水环境中含量丰富。由于北极已经经历了快速的气候变化，这些水库的甲烷排放量增加对我们的气候系统构成了威胁。我的研究小组主要研究北极的二氧化碳，但我们最近与一个合作实验室一起对努纳武特的剑桥湾附近的溶解甲烷进行了一些测量。我们的初步结果非常令人兴奋。我们已经发现，在冬季，甲烷积累在格雷纳湖的冰冻表面之下--格雷纳湖是剑桥湾附近的一个大而浅的湖。春天，随着湖冰的破裂，大量的甲烷沿着淡水河流向海洋。在海洋环境中，一些甲烷被释放到大气中，但一些被困在海冰下数周。在这个NSERC-RTI拨款申请中，我们正在申请资金购买一个多功能的溶解甲烷分析仪，安装在配备雪地摩托履带的全地形车上。有了这个系统，我们将绘制Greiner湖产生甲烷的区域，跟踪它沿淡水河的传输，并绘制海冰下形成的羽流。在海冰之下，我们将寻找微生物消耗甲烷的证据。如果甲烷在海冰下被移除，我们将发现北极甲烷循环中一个重要的、以前未知的部分。如果不购买这种仪器系统，我们将无法验证我们的假设，并了解这些过程在整个北极地区的重要性。在让我们能够立即回答这个及时的研究问题的同时，该仪器还将为我们的团队开辟新的研究领域。我们希望利用该系统研究其他北极湖泊中的甲烷，并调查其他河流系统以及它们如何与海洋环境相互作用。在夏天，我们将把甲烷传感器放在研究船上，研究北极沿岸沃茨中溶解的甲烷。未来，我们将在该平台上添加其他仪器，使其功能更加丰富。我们预计，研究生、博士后研究员和北方（即因纽特人）研究助理进行研究时，将几乎不断地使用该系统。所有这些高素质的人员将发展甲烷监测技能，这些技能在加拿大各地都有市场，在加拿大，自然景观和工业过程中甲烷排放的检测变得越来越重要。

*********Methane (CH4) is an important greenhouse gas. Although it is less abundant in our atmosphere than carbon dioxide (CO2), its climate impact per molecule is about 30 times higher. Like CO2, methane has natural and human sources, and accounting for both is important for accurate climate predictions. There is significant concern that as our climate warms, large reservoirs of natural methane may be released to the atmosphere, amplifying warming. The Arctic methane reservoir is massive, with significant quantities in permafrost soils, seafloor sediments, and in marine and freshwater environments. Since the Arctic is already experiencing rapid climate change, enhanced methane emission from these reservoirs is a threat to our climate system.******My research group mostly studies CO2 in the Arctic, but with a collaborating lab we recently made some measurements of dissolved CH4 near Cambridge Bay, Nunavut. Our preliminary results are very exciting. We have discovered that over the winter, methane accumulates beneath the frozen surface of Greiner Lake – a large, shallow lake near Cambridge Bay. In the spring, as the lake ice breaks up, a large amount of that methane travels down Freshwater Creek to the ocean. In the marine environment, some of the methane is released to the atmosphere, but some is trapped beneath the sea ice for several weeks. In this NSERC-RTI grant application, we are applying for funds to purchase a versatile dissolved methane analyzer, mounted on an all-terrain vehicle equipped with snowmobile tracks. With this system, we will map the areas generating methane in Greiner Lake, follow its transit down Freshwater Creek, and map the plume that forms beneath the sea ice. Beneath the sea ice, we will look for evidence that microbes are consuming the methane. If CH4 is being removed beneath the sea ice, we will have discovered an important, and previously unknown part of the Arctic methane cycle. Without the purchase of this instrument system, we will be unable to test our hypotheses, and learn how important these processes are across the Arctic.******While allowing us to immediately answer this timely research question, the instrument will also open up new research areas for our team. We expect to use the system to study methane in other Arctic lakes, and to investigate other river systems and how they interact with the marine environment. In the summer, we will put the methane sensor on research ships to study dissolved CH4 in coastal waters across the Arctic. In the future, we will add other instruments to the platform, making it even more versatile. We anticipate near-constant use of the system by the graduate students, postdoctoral fellows, and northern (i.e. Inuit) research assistants conducting the research. All of these highly qualified personnel will develop methane monitoring skills that are marketable across Canada, where detection of methane emissions from natural landscapes and industrial processes is becoming increasingly important.**