CONCLUSION
Here we show that S. fuscum’s photorespiration is suppressed,i.e. net photosynthesis increased, in response to the last
century’s increase in atmospheric CO2. This response was
highly dependent on WT, with water-saturating conditions abolishing the
CO2 effect. Although those conditions are not typical
for hummocks, they frequently occur for lawns. Lawns did not show any
suppression of photorespiration, neither under water-saturation nor
under optimal moisture conditions, suggesting a reduced
CO2 effect for those microhabitats. Variations in
temperature and light intensity did not affect the extent of the
CO2-driven suppression of photorespiration. Our study
revealed that D isotopomers are a valuable tool for understand metabolic
C fluxes in Sphagnum . The results presented in this study will
allow validation of D isotopomer analysis of peat archives and provide
the basis for modelling global peatland C fluxes.