Multiple trophic levels fueled by recirculation in the Columbia River plume

Large rivers represent gateways for the transport of terrigenous and anthropogenic material to the coastal ocean. Here we document a ~700 km² recirculation or bulge associated with the Columbia River plume that retains recently discharged river water sufficiently to create a regional bioreactor. Fueled by a river nitrate source, this feature stimulated growth across three trophic levels and may buffer this gateway system during periods of increased warming and stratification that lead to decreased ocean productivity, potentially enhancing production at multiple trophic levels and enriching surface waters far from the river mouth.