Critical Changes to Peatland Carbon Biogeochemistry Following Permafrost Thaw
Critical Changes to Peatland Carbon Biogeochemistry Following Permafrost Thaw
Previously Published Material: A small subset of the proposed presentation is from a manuscript that has been submitted and is currently under review. Data from this manuscript was also presented at the following conferences: AGU fall meeting 2014 and EUCOP 2014.Majority of the presentation material is new and based on another manuscript that is currently in preparation for submission. The proposed presentation will synthesize and build upon the 2 aforementioned manuscripts, drawing big-picture conclusions on biogeochemical changes in peatlands following permafrost.
Abstract ID#: 36731
English Abstract:
Permafrost peatlands contain significant stores of soil carbon (C) and the fate of this C is uncertain in light of the warming north. With ongoing and projected degradation of permafrost, release of permafrost C is considered a highly likely positive feedback to climate change. To quantify the magnitude of C loss following permafrost thaw in peatlands, several studies have investigated changes in ecosystem structure (vegetation and hydrology) and associated function (C cycling). Based on current literature, we developed a conceptual framework to summarize key changes in structure and function after thaw. Subsequently, we tested hypotheses generated from this conceptual framework, along a wide range of permafrost thaw conditions. Data will be presented on the abiotic and biotic correlates of litter decomposition as well as carbon dioxide and methane fluxes in a thawing landscape. Our results suggest that the dominant controls on C cycling vary significantly, depending on the degree of permafrost thaw. Across the thaw gradient, indirect pathways (change in vegetation due to change in moisture and temperature) have a more pronounced effect on litter decomposition rates than direct pathways (change in temperature and moisture). We will present a revised conceptual framework of peatland C biogeochemistry following permafrost thaw and propose landscape level integrator variables of C function for these spatially heterogeneous landscapes.