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

点击翻译按钮获取中文摘要

*********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.**