Greenhouse Gas Dynamics Across the Land-to-Ocean Continuum in the Canadian Archipelago

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Current and future warming has the potential to impact the cycling of methane in the Arctic, and the contribution of the region to the global methane budget remains poorly constrained. Thawing of permafrost, as well as melting of ice, has the potential to mobilize significant quantities of methane. This project focuses on understanding the connection between lakes, rivers, and bays across the land-ocean continuum in northern Canada. Methane and carbon dioxide from terrestrial and freshwater systems can be mobilized during the spring thaw and rapidly transported into the coastal ocean. The investigators will use unmanned vehicles to study the fate of these gases as they are transported via small river networks to the coastal ocean and subsequently outgassed as sea ice breaks up. Broader impacts of this project include developing new technology for Arctic research, training a female graduate student in polar field work and engineering, and engagement with local indigenous communities.The contribution of Arctic fresh water bodies to the global methane budget is poorly constrained. This project will use a cutting-edge autonomous surface platform to measure dissolved methane, carbon dioxide, salinity, nitrate, and oxygen in surface waters of Cambridge Bay, Canada. The investigators will quantify the magnitude of the rapid burst of outgassing of methane and carbon dioxide with two field seasons of intensive spatial and temporal sampling during the weeks surrounding the spring freshet. The specific objectives are to: characterize the rapid lateral pulse of greenhouse gases entering the coastal ocean from terrestrial aquatic systems during the freshet; determine the extent to which methane and carbon dioxide accumulates under ice; quantify the geographical extent and rate of rapid outgassing to the atmosphere; and close a mass balance of the Cambridge Bay to determine if the majority of methane and carbon dioxide delivered to the coastal ocean outgasses. The investigators will also provide proof of concept for autonomous vehicles carrying sensor technology that can expand our spatial and temporal sampling capability in dangerous or harsh environments.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.