Nutrient fluxes via submarine groundwater discharge to the Bay of Puck, southern Baltic Sea

► SGD fluxes were measured, and seepage water collected, by means of seepage meters. ► Both groundwater and recirculated seawater end-members were quantified. ► Nitrogen(N) and Phosphorus(P) loads were scaled up to the Puck Bay and Baltic Sea. ► N and P loads to the Puck Bay were significant at the background of other sources. ► SGD contributed significant P proportion of Baltic Sea nutrient budget.