OCE-9413249 This project will involve studies of the role of diatoms in new production and in downward flux of biogenic silica, particulate organic carbon, and nitrogen in oceanic areas of low biomass, particularly the Southern and the subtropical Pacific Oceans. The role of diatoms in oligotrophic ocean systems is not well- understood and may have been underestimated in the past. The ocean regions of study and comparison are both important in the overall effort to improve understanding of ocean fluxes.