We estimated the bacterial production and losses to predators along an open ocean trophic gradient from coastal upwelling waters to oligotrophic waters in the Subtropical Northern Atlantic Ocean. Two zonal sections (21 and 268N) extending from the NW African shelf to the Open Atlantic Ocean at 268W were sampled during September– October 2002 (autumn), and May – June 2003 (spring). The main goal was to elucidate whether the impacts of bacterial losses were more import-ant in upwelling rather than in offshore waters. Whereas temperature and salinity decreased and nutrient concentrations increased from offshore to the coastal upwell-ing regions, phytoplankton, ciliate and bacterial biomass followed a similar trend in-creasing towards the upwelling zone. In addition, heterotrophic nanoflagellate biomass, bacterial production and grazing rates on bacteria did not follow this pattern, although the highest activities were recorded at upwelling stations. However, at the stations not affected by upwelling the average impact on bacteria expressed as a percentage of bacterial production consumed by predators in autumn available online at www.plankt.