A relationship between phytoplankton and bacterioplankton has been observed in a laboratory experiment, simulating partial and complete upwelling conditions. Primary and bacterial productivity presented a similar pattern, with a three-stage development (growth, peak and decline in production). However, bacterial development stages did not occur simultaneously with the phytoplanktonic development, that is, the highest bacterial production rates occurred in the stages of growth and decline of the primary production, whilst the lowest values of bacterial productivity were simultaneous to the highest phytoplanktonic production stage. Analysis of data obtained in this experiment shows a close relationship between phytoplankton and bacteria, in which these organisms might be competing for inorganic nutrients in some moments, and bacteria might have, as an important source of carbon, the particulate or dissolved organic matter coming from the phytoplankton. Besides that, bacteria might play an important role in the initial stages of phytoplankton blooms, when they might be one of the main conditioning agents of the waters that have just upwelled, allowing the plain phytoplanktonic development.
Primary production; Bacterial production; Plankton; Upwelling; Arraial do Cabo; Brazil