Importance of sub-surface rhizosphere-mediated coupled nitrification-denitrification in a flooded agroecosystem in Hawaii

►We examine the effect of emergent macrophytes on the nitrification-denitrification pathway. ► We use a modified 15NH4+ whole core perfusion technique in a flooded agricultural wetland. ► Vegetation enhances sub-surface coupled nitrification-denitrification versus control cores. ► Air movement has a large positive effect on sub-surface coupled nitrification-denitrification. ► Sub-surface N losses were more important than losses from the surface oxic/anoxic interface.