A multidisciplinary study of VERtical Transport and EXchange of material in the upper ocean performed in the California Current. It was organized to investigate the vertical exchange of materials between the photic zone and deeper waters in the Pacific Ocean. VERTEX was one of the first larger scale programs to focus on the couplings between new production and export. Components involved the use of particle traps and subsequent analyses of trapped particles for major elements, trace elements, radionuclides, fecal pellets and microbial populations to estimate vertical particulate fluxes.