This project constitutes a part of the United State Joint Global Ocean Flux Study to be conducted in the Central Equatorial Pacific in 1992. Metazoan zooplankton have been identifies as the most likely agents for particle transformation and subsequent export of organic matter to deeper ocean layers. Thus, understanding the functioning and assessing the efficiency of the biological pump, that is the downward fluxes of carbon and nitrogen resulting from the balance of production and consumption of biological material by the pelagic community, requires knowledge of the rates at which zooplankton consume and transform suspended particles. This project will examine in detail the role of metazoa zooplankton in the biological pump of the central equatorial Pacific Ocean. Sophisticated techniques will be used to assess the variability in the upper 200 m of mesozooplankton biomass, grazing rates and fecal matter production rates. Size specific and community based rates of phytoplankton consumption will be compared with phytoplankton production and fecal matter production will be related to particulate organic carbon and nitrogen fluxes to establish what percentage of the photosynthetically fixed carbon is ingested and potentially exported to deeper zones. This project will provide critical information necessary to quantify the flow of carbon and nitrogen in the upper layers of the central equatorial Pacific.