Carbon dioxide fluxes on Canadian Arctic Tundra

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The Arctic is experiencing unprecedented change due to global warming. Ecosystem processes, such as the exchange of carbon dioxide between tundra and atmosphere, are impacted by this warming. Our ability to predict future climate rests on understanding these changes. For the past eight years I have been building a research program with my students and collaborators to investigate Arctic tundra-atmosphere carbon dioxide exchange near Daring Lake, NWT, where carbon dioxide flux stations are set up in four different tundra environments. It is now the longest running and most extensive carbon flux measurement program in Arctic Canada. I am proposing to expand this research to address new crucial scientific issues that will improve out understanding of Arctic tundra processes and thus, generate knowledge that will assist in predictions of future climatic change. I will investigate how variations in plant growth, expressed as leaf area, control seasonal and interannual variations in carbon dioxide fluxes and compare these with climate factors such as temperature and precipitation. It is hypothesized that the plant factors are only indirectly related to climate factors and are more important than climate for determining the total amount of atmospheric carbon dioxide absorbed by the tundra. I will also explore novel ways for monitoring these vegetation changes, and ultimately carbon dioxide fluxes, which can be extrapolated to large geographic areas. I will extend the measurements into the late-winter and autumn seasons when we believe that the loss of carbon dioxide from the tundra is significant. In the past, due to technological limitations, measurements were primarily restricted to the snow-free growing season, but this can now be overcome with updated equipment and will give us the information needed to construct accurate annual carbon budgets for tundra ecosystems. This research will advance our knowledge of tundra processes and climate feedbacks, address the lack of carbon flux research in the Canadian Arctic, train new students in Arctic environmental science and ultimately, benefit northerners by improving climate predictions that will help communities plan for and adapt to climate change.