Variations du volume et des quotas en N et P d'Alexandrium tamarense (dinoflagellata) en culture continue limitante en nitrate

N-limited continuous growth of the dinoflagellate Alexandrium tamarense was performed by applying soft mixing conditions to the culture medium by means of air bubbling and slow rotation of a stirring bar. The cellular nitrate + nitrite and phosphate content and cell volume of Alexandrium tamarense were measured at different dilution rates from 0.05 to 0.37 d(-1). Cell volume varied from 11500 to 31000 mu m(3) between these extremes, indicating a significant positive correlation between cell volume and dilution rate. The analyses also reveal a strong interdependence of cell size and NO3- + NO2- cellular content, the latter increasing from 0.09 to 1.1 pmol cell(-1) with increases in cell size. The positive relationship between cell size, NO3- + NO2- cell content and dilution rate is discussed in terms of the implication of such parameters in the proliferation of this dinoflagellate in a natural environment.