Tuula Larmola, Jill L. Bubier, Sari Juutinen, Elyn Humphreys, Tim R. Moore
Proceedings of the 14th International Peat Congress
c-balance, co2, nitrogen, photosynthesis, respiration
Theme X. Peatland carbon budgets and greenhouse gas (GHG) fluxes
We investigated vegetation and ecosystem CO2 exchange at Mer Bleue Bog, Canada that has been fertilized with nitrogen, phosphorus and potassium or with nitrogen only for 7−12 years. Gross photosynthesis, ecosystem respiration and net CO2 exchange were measured weekly during May−September 2011 using chambers and the seasonal CO2 balance reconstructed using environmental time series. The highest nutrient additions were associated with 40% less net CO2 uptake than in the control. A weaker C sink potential could be explained by changes in availability of nutrients limiting plant and microbial growth, a shift in biomass allocation to woody tissues, loss of Sphagnum moss and peat decomposability.