Matthias Peichl, Jörgen Sagerfors, Mikaell Ottosson-Löfvenius, Mats Nilsson
Proceedings of the 14th International Peat Congress
Theme X. Peatland carbon budgets and greenhouse gas (GHG) fluxes
The important role of natural peatland ecosystems in the global carbon (C) cycle and its susceptibility to changes in climate patterns have been recognized and thus, identifying effects from climatic controls on the long-term peatland C sequestration potential has become a focus of concern in recent years. We present results from ten years (2001 to 2010) years of carbon dioxide (CO2) exchange measurements in an oligotrophic minerotrophic peatland in Northern Sweden using the eddy-covariance technique. The seasonal patterns and inter-annual variation of the peatland net ecosystem exchange (NEE), gross ecosystem production (GEP) and ecosystem respiration (ER) and their underlying climatic andenvironmental controls were explored. The results suggest an annual net uptake of CO2 commonly within the narrow range of -48 to -66 g C m-2 y-1 (for eight out of the ten years) and a decadal average (± standard deviation) of 57 ± 24 g C m-2 y-1. The exceptions were the years 2006 and 2008 in which the annual NEE was -17 and -113 g C m-2 y-1, respectively. Lower CO2 uptake in 2006 occurred due to a late summer drought period and its associated reduction of GEP. Such deviation from the long-term mean indicates the possible negative implications of a future drier and warmer summer climate on the northern peatland CO2 uptake potential. Nevertheless, overall this peatland persisted as continuous sink for atmospheric CO2 under various climatic conditions indicating some general stability of the ecosystem functioning and resilience to moderate inter-annual climate variations.