The central North Pacific is one of the more oligotrophic regions of the world oceans. There the particulate organic nitrogen:cabon ratio of surface waters is variable and less than the Redfield ratio of 16N:106C by atoms. The phytoplankton P/B ratio based upon both C and N assimilation rate varied directly with the particulate matter PON:POC ratio as did the productivity index [mg C (mg chl a)−1h−1]. At steady state the doubling time of the phytoplankton, the turnover time of the limiting nutrient supplied via herbivore grazing, and the time for herbivores to filter a unit volume of water would be equivalent. They appear to be of the order of 5–9 days based on present methodology and straightforward interpretation of its results.