Summer carbon dioxide and water vapor fluxes across a range of northern peatlands

摘要: [1] Northern peatlands are a diverse group of ecosystems varying along continuum hydrological, chemical, and vegetation gradients. These contain about one third the global soil carbon pool, but it is uncertain how water cycling processes response to climate change differ among peatland types. This study examines midsummer CO2 H2O fluxes measured using eddy covariance technique above seven northern including low-shrub bog, two open poor fens, wooded moderately rich extreme-rich fens. Gross ecosystem production respiration correlated positively with indices each other. Consequently, 24-hour net exchange was similar most sites (an average sink 1.5 ± 0.2 g C m−2 d−1) despite large differences in table depth, chemistry, plant communities. Evapotranspiration primarily radiatively driven at all decline surface conductance increasing vapor deficit indicated physiological restrictions transpiration, particularly woody less 100% Sphagnum cover. Despite these differences, midday evapotranspiration ranged only from 0.21 0.34 mm h−1 owing compensation factors controlling evapotranspiration. Water use efficiency varied as result productivity functional type. Although classification includes great variety characteristics, type may not be an effective way predict magnitude characteristics exchanges.