Since November 1995, the CARIACO Ocean Time Series program has been studying the relationship between surface biogeochemical processes and the vertical fluxes of carbon and nutrients in a continental margin setting influenced by seasonal upwelling. This tectonic depression, located on the continental shelf of Venezuela, shows marked seasonal and interannual variation in hydrography and primary production induced in part by the regular migration of the Intertropical Convergence Zone (ITCZ). Between December and May, the Cariaco Basin experiences dry, upwelling-favorable weather. This leads to primary production of ~1.4 gC m-2 d-1 (upper 100 m). From June to November is the rainy season, winds are weaker and upwelling is reduced; primary production falls to half the rate observed during upwelling. The ultimate goal of CARIACO is to understand how meteorological and upper ocean hydrographic conditions affect primary production, dissolved inorganic carbon, CO2 fugacity, bacterial productivity and respiration, and vertical particle fluxes, and how variation in these parameters are reflected in the basin's sedimentary record, which is well known for storing high-frequency global climate signals.