Abstract
The chemical composition of oceanic phytoplankton (by atoms) typically occurs in the proportions C106 N16 P1. Yet, in laboratory growth conditions these proportions are only observed for marine phytoplankton at high growth rates when non-nutrient limitation is approached. Thus growth rates of natural phytoplankton populations in oceanic waters may be near maximal and hence non-nutrient limited. The uniformly low biomass and residual nutrient levels in such waters does not preclude the possibility of high growth rates because Zooplankton grazing and nutrient regeneration within the euphotic zone may keep this highly dynamic system in a balanced state.