Growing Season Dynamics in Methane Fluxes at a Northern Boreal Sedge Fen

Lohila A., Aurela M., Hatakka J., Penttilä T., Minkkinen K. and Laurila T.

Proceedings of the 14th International Peat Congress


automatic-chamber, eddy-covariance, methane-concentration, methane-flux

Lohila et al 2012: Growing Season Dynamics in Methane Fluxes at a Northern Boreal Sedge Fen


Theme X. Peatland carbon budgets and greenhouse gas (GHG) fluxes


Methane (CH4) is a powerful greenhouse gas, one of its main natural sources being northern circumpolar wetlands. During the short growing season of northern mires, the temporal variation in CH4 emission is high, the flux increasing with the emergence of mire vegetation and the peat temperature. Still little is known about the more short-scale variations, e.g diurnal cycle, and the factors controlling the peat-atmosphere exchange. We have measured CH4 exchange in 2007–2010 in a northern boreal fen Lompolojänkkä (69 deg N, 24 deg E) with two automated chambers operating with closed dynamic principle. With these opaque chambers also carbon dioxide (CO2) flux, equalling the total ecosystem respiration, has been measured simultaneously. Concentrations of CH4 and CO2 in the peat have been monitored daily throughout the year, using a 50 m long tubing installed into the peat at a depth of 0.15 m. In this presentation we will study the driving factors behind the short-term temporal variation in CH4 flux, and discuss their relationship with the CH4 concentration in the peat. Comparison of different flux measurements (manual chambers, eddy covariance), offering information about the spatial variation, will be shown.