Carbon fluxes of an alpine peatland in Northern Italy

It is widely known that peatlands are a significant carbon (C) stock. Most peatlands are located in boreal and subarctic regions of the northern hemisphere but some occur also at high altitude and, contrary to the first; their contribution in terms of carbon sequestration is far less studied. In the Alps, there are numerous small peatlands, which are threatened by increasing temperatures and an alteration of their water balance. The aim of this study was to investigate the carbon fluxes of a small-scale fen in the Alps over three years (2012–2014). During the study period, the peatland experienced a high interannual variation in weather conditions while it acted as a carbon source based on CO2 emissions (NEE: 180.7 ± 65.2 g C CO2m−2 yr−1) for all three years. This was mainly due to the short net C uptake period (73 ± 7 days) and high respiration. Ecosystem respiration and summer gross primary production were both very high compared to other peatlands around the world and compared to a nearby low productive grassland. In wintertime, the soil did not freeze, resulting in a slow decomposition of the organic matter. Low methane fluxes were recorded during a 10-month measurement campaign, for a total of 3.2 g C CH4m−2 over the December 2013–September 2014 period. Our findings suggest that the interannual variability of temperature and soil water content exert a strong influence on the carbon balance of peatlands of the Alps and that could further worsen depending upon the magnitude of climate change.