The northwest Iberian ocean margin experiences seasonal upwelling of nutrient-rich water resulting in enhanced primary productivity. The quantitative organic-walled dinoflagellate cyst distribution and that of other palynomorphs has been determined in 37 box core-tops along three transects to trace the upwelling signal. Oligotrophic Impagidinium spp. represent the dominant offshore elements. Cysts of heterotrophic Protoperidinium spp. mainly occur in sediments of the seasonal upwelling area on the shelf and slope and show a sharp decrease offshore. The eutrophic autotrophic taxon Lingulodinium machaerophorum is also abundant in sediments of the seasonal upwelling area on the shelf and slope, and also decreases more offshore. Both relative as well as absolute numbers of these taxa may be used to trace the upwelling system despite potential taphonomic problems. Considering the overall similar environmental conditions with respect to the other two transects, the elevated palynomorph concentrations in the shielded Nazare ¤ Canyon samples may be seen to represent the actual fluxes of palynomorphs along the Iberian coast. If accepted, this would indicate a preservational and transport loss of cysts of an order of magnitude in other transects. ß