Bonnie De Baets
Ph.D. student
Department of Earth and Planetary Sciences
McGill University

Supervised by:

Peter Douglas (Regular member)

Research project description

Using clumped isotopes to detail methane cycling in the permafrost active layer in northern Canada

Introduction: The mechanisms driving methane emissions from the Arctic are not understood. To comprehend Arctic emissions, sources and production processes need to be ascertained. Methane cycling in the permafrost active layer (PAL) is an important aspect. The PAL is made of organic-rich soils that thaw and freeze seasonally, though it is now thickening due to climate change. This allows for previously dormant organic materials to act as new source material for microbial activity, potentially resulting in an increased contribution of methane to the atmosphere. Isotope measurements that can decipher the processes involved in methane formation and consumption in the environment will be used. As standard stable isotope techniques alone are often ambiguous this work will make use of newer methodologies through the employment of clumped isotopes. Clumped isotope measurements in permafrost environments are hypothesized to be controlled by the rate of methane production, this has not been fully tested. Objectives: The overall objective of the project is to study methane emitted from the permafrost active layer as a result of anthropogenic climate change. A technical objective of this project is to refine the methane clumped isotope technique using real-world, in-situ measurements from permafrost landscapes. With this information, the aim is to better understand what the results of this technique tells us about the microbial activities occurring in the permafrost active layer and what the impacts of those activities could be. Study sites: The first research location is on Bylot Island, located just north of Baffin Island in Nunavut. Samples will be collected from permafrost thaw ponds in a polygonal patterned ground environment. The second research location is along the Dempster Highway in the Northwest Territories. Samples will be collected in peat-dominated areas.Material and methods: To achieve the research project’s objectives, gas samples will be collected from the research locations for analysis. In the ponds, ebullition gases will be collected through the use of floating bubble traps. In the peat, customized sampling units were constructed to be able to passively collect gas at depth from the areas. These gas samples will be analysed for stable, radio and clumped isotopes of methane. Expected results: This new data on permafrost methane emissions and isotope ratios will ultimately improve our understanding of why methane emissions are increasing, and what the implications of this are for carbon cycle feedbacks to climate change.

Research Site Coordinates

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