Results/Conclusions Fluxes of CH₄ were reduced in planted units, aerated units and during the winter likely as a function of greater oxygenation under these conditions. Fluxes of CO₂ were higher in planted units and during the summer, and this may be due to higher microbial respiration rates in these treatments. Fluxes of N₂O were higher in units planted with P. australis and during the summer, but the high variability in fluxes observed for this gas prevented the identification of any clear pattern. Globally, T. angustifolia had the lowest GHG production among the macrophyte species surveyed. Global warming potential (GWP) was higher in unplanted units, non-aerated units, and during the summer. Methane was the main contributor of GWP in non-aerated units, whereas CO₂ was the most important GHG in planted and aerated units. N₂O had a minor contribution to GWP in all treatments. We found that artificially aerated and planted units (especially those with T. angustifolia) had the overall best performance among the treatments tested in this study, with the lowest GWP, the highest removal efficiencies and the best hydraulic properties.