CO2 fluxes in peatlands under varying temperature and moisture conditions

In spite of the large carbon store in mire ecosystems, the annual unbalance between the binding and release of carbon is quite small. In most mires, over 90 % of the carbon fixed in photosynthesis is released annually in soil respiration. The predicted atmospheric and climate change would alter the factors regulating production and decomposition. In many scenarios the summertime soil moisture has been thought to decrease in large areas of the boreal region. This would lead to the increasing variation of the water table in peatlands and to increase of the aerobic decomposition during the dry period. The climatic warming would still enhance this effect. One possibility in examining the long-term effects of the reducing soil moisture is to compare virgin and drained mires. Here the CO2 fluxes, temperature and water level of peat was measured both in virgin mires and mires drained 20-50 years ago. The measurements were made in varying weather conditions resulting in CO2 flux data from a wide range of water tables. The data thus represent both the CO2 fluxes in the present conditions, and the estimates for the predicted future moisture regime