Effects of Warming and Permafrost Thaw on Carbon Dioxide Fluxes from Boreal Peatlands in northwestern Canada

Abstract

<p>The Taiga Plains ecozone in northwestern Canada is warming rapidly which alters the carbon dioxide (CO₂) fluxes of the boreal peat landscape in two ways: 1) directly by increasing temperatures going along with increasing fluxes and 2) indirectly via permafrost thaw and resulting wetland expansion. However, we still lack an understanding of how direct and indirect effects vary across a latitudinal climate gradient covering different extents of permafrost. In this study, we will compare two years of concurrent eddy covariance measurements made over forested permafrost peat plateaus at Smith Creek (discontinuous permafrost) and Scotty Creek (sporadic permafrost) to assess differences in net CO₂ exchange and its two component fluxes, gross primary productivity (GPP) and ecosystem respiration (ER). Footprint analysis will be used to assess the net CO₂ balance of peat plateaus and thermokarst wetlands at both sites. We hypothesize that GPP and ER will be higher at the warmer Scotty Creek site, due to both, more abundant thermokarst wetlands and higher GPP and ER of peat plateaus at this southern site. We also hypothesize that the effects of warming on GPP are greater than on ER and thus that the warmer Scotty Creek site is a greater net CO₂ sink. Our study will conclude on the carbon feedback of warming peat landscapes near the southern limit of permafrost in northwestern Canada in response to Climate Change.</p>