Production primaire et activité bactérienne en eutrophisation expérimentale (lagune du Brusc - Automne 1977)

An experimental eutrophication carried out with several technics on mediterranean sea water (Embiez) in autumn shows : - significant variations in the electro-chemical composition of phytoplanktonic excretion ; complex organic substances are excreted during two different periods, especially after the Skeletonema costatum bloom ; - close relations between heterotrophy (14c glucose test) and excretion of organic matter by photosynthetic organisms, glucids are always predominant ; - the original heterotrophy from the 14c pyruvate test ; which is obviously more selective than the 14c glucose test ; - the existence of different periods of active ultraplankton.