Decomposition Dynamics Under Climate Change Conditions in Boreal Peat

Boreal peatlands currently act as carbon sinks, but are projected to become carbon sources under climate change. Shifts in plant community composition alongside increased decomposition rates are potential mechanisms precipitating this change. My objective was to determine the decomposition potential of different peatland plant litters (Sphagnum magellanicum (peat moss), Carex magellanica (graminoid) and Chamaedaphne calyculata (woody shrub)) during short-term (48 hour) leaching and microbial decomposition (20 week) phases. The 48-hour leaching experiment measured mass loss and leachate chemistry of litters grown under ambient and elevated CO2, while the 20-week experiment measured heterotrophic respiration and mass loss of litters incubated at 11.5, 15.5 and 19.5 °C. In both experiments, Ch. calyculata and Ca. magellanica were more decomposable compared to S. magellanicum. My results suggest that decomposition rates under climate change will increase due to direct temperature effects as well as through potential shifts in plant communities