Influence of restored mussel reefs on denitrification in marine sediments

Globally we have lost the majority of shellfish reefs, with the concomitant loss of ecosystem services. Restoration provides opportunities to regain lost services and engage society in the wider ecosystem benefits of restoration. Previous research has demonstrated that the functional role of shellfish can be context dependent, and we therefore measured fluxes of nutrients and dissolved gases from four restored mussel reefs along a grain size gradient in New Zealand as a metric of success in ecosystem function. This globally novel research found that restored mussel reefs were successful in enhancing denitrification. Mussel reefs can therefore be important in reducing the risk of future eutrophication, but the importance of nutrient remineralisation varies in response to site conditions. These data show that mussel reef creation can quickly restore ecosystem function, but site selection to enhance specific services is important. This study provides evidence of a poorly realised ecosystem service provided by restored mussel beds that allows future restoration efforts to better target areas in order to have the largest impact on the removal of anthropogenic nitrogen. •In situ chambers were used to measure nutrient and denitrification fluxes in and out of restored mussel reefs.•Restored mussel reefs enhanced denitrification, especially in sandier habitats.•Restoration can quickly restore ecosystem function, but site selection is important.