Küresel iklim değişikliği bağlamında Yeniçağa Gölü turbalık alanlarında (Bolu) uzun dönemli CO2, H2O ve enerji akılarının izlenmesi

Peatland ecosystems play a crucial role in global carbon (C) cycle as being significant C stocks even though they spatially cover only 5 % of the terrestrial biosphere. Human-induced disturbances including global climate change threaten their ability to continue to behave as a C sink. This study of quantification of carbon dioxide (CO2), water and energy fluxes is the first one conducted for a peatland (Yeniçağa peatland) in Turkey for a monitoring period of three years (from August 2010 to June 2013). CO2, energy and water fluxes were measured using an EC technique, in addition to the ancillary measurements of soil and litterfall C:nitrogen (N) ratios, litterfall lignin content, aboveground biomass, and decomposition rate. Mean peat soil C and N contents were 23.3 % and 1.7 %, respectively. The decomposition constant (-0.006) of soil organic matter (SOM) showed a high decomposition rate with low quality litter (C:N = 18.8, Lignin = 7.2 %), and thus, a positive effect on CO2 efflux. Aboveground biomass peaked in the months of June and August. Hourly net ecosystem exchange (NEE) varied between -1.0 and 1.5 mg CO2 m-2 s-1. The peatland acted as a sink in only June for 2011, a sink from May to July for 2012 and a sink in only May for 2013. The cumulative annual NEE was 352.7, 283.8, 252.4, and 142.6 g C m-2 for 2010, 2011, 2012, and 2013, respectively. Ecosystem respiration (Reco) and gross primary productivity (GPP) were partitioned using an algorithm for partitioning carbon components. The cumulative annual Reco was always higher than GPP which indicated the high CO2 source strength of the peatland. The correlation analysis of the partitioned carbon components (NEE, Reco, and GPP) with environmental variables pointed to their highest correlations with air temperature (Tair), vapor pressure deficit (VPD) and evapotranspiration (ET) for all the years. As a result, the regression models obtained for GPP and Reco showed higher r2adj values (52 % < r2adj < 78 %) than those for NEE (36 % < r2adj < 61 %). The water budget of the peatland showed a constant state of water deficit as ET > PPT for the study period. Energy balance closure of the EC flux system was assessed using net radiation (Rn), soil heat flux (G), latent heat flux (LE) and sensible heat flux (H) components and found to be 0.62 and 0.64 for 2011 and 2012.