Environmental and taxonomic controls of carbon and oxygen stable isotope composition in Sphagnum across broad climatic and geographic ranges

• Authors: GRANATH Gustaf; RYDIN Hakan; BALTZER J.L.; BENGTSSON F.; BONCEK N.; BRAGAZZA L.; BU Z.J.; CAPORN S.J.M; DORREPAAL E.; GALANINA O.; GAŁKA M.; GANEVA A.; GILLIKIN D.P.; GOIA I.; GONCHAROVA N.; HÁJEK Michal; HARAGUCHI A.; HARRIS L.I.; HUMPHREYS E.; JIROUŠEK Martin; KAJUKAŁO K.; KAROFELD E.; KORONATOVA N.G; KOSYKH N.P.; LAMENTOWICZ Mariusz Grzegorz; LAPSHINA E.; LIMPENS J.; LINKOSALMI M.; JIN-ZE Ma; MAURITZ M.; MUNIR T.M.; NATALI S.M.; NATCHEVA R.; NOSKOVA M.; PAYNE R.J.; PILKINGTON K.; ROBINSON S.; ROBROEK B.J.M.; ROCHEFORT L.; SINGER D.; STENOIEN H.K.; TUITTILA E.S.; VELLAK K.; VERHEYDEN A.; WADDINGTON J.M.; RICE S.K.
• Year of publication: 2018
• Type: Article in Periodical
• Magazine / Source: Biogeosciences
• MU Faculty or unit: Faculty of Science
• Doi: http://dx.doi.org/10.5194/bg-15-5189-2018
• Keywords: MIXED-EFFECTS MODELS; WATER-CONTENT; TESTATE AMEBAS; FUSCUM PEAT; PHOTOSYNTHESIS; CELLULOSE; MOSS; DISCRIMINATION; FRACTIONATION; VARIABILITY
• Description: We analysed two important peat-forming Sphagnum species (S. magellanicum, S. fuscum) samples from 93 sites across North America and Eurasia. There were differences in delta13C values between species. For S. magellanicum delta13C decreased with increasing height above the water table and was positively correlated to productivity. Together these two variables explained 46% of the between-site variation in delta13C values. For S. fuscum, productivity was the only significant predictor of delta13C but had low explanatory power. For delta18O values, approximately 90% of the variation was found between sites. Globally modelled annual delta18O values in precipitation explained 69% of the between-site variation in tissue delta18O. S. magellanicum showed lower delta18O enrichment than S. fuscum. Elevation and climatic variables were weak predictors of tissue delta18O values after controlling for delta18O values of the precipitation. To summarize, our study provides evidence for (a) good predictability of tissue delta18O values from modelled annual delta18O values in precipitation, and (b) the possibility of relating tissue delta13C values to HWT and NPP, but this appears to be species-dependent. These results suggest that isotope composition can be used on a large scale for climatic reconstructions but that such models should be species-specific.