STEADY-STATES OF SEMICONTINUOUS CULTURES OF A MARINE DIATOM - EFFECT OF SATURATING NUTRIENT CONCENTRATIONS

The evolution of nitrogen incorporation, the C-N ratio and chlorophyll content were studied in semicontinuous, light-dark synchronised cultu res of the marine diatom Phaeodactylum tricornutum Bohlin, maintained under conditions of limiting to highly saturating nutrient concentrati ons and at different dilutions. The behaviour of cultures diverged fro m the expected since a decrease in the nitrogen cellular quota and a s table chlorophyll a-C ratio was recorded under nutrient-sufficient con ditions, indicating that current theories on continuous cultures canno t be applied directly to semicontinuous cultures when maintained under highly nutrient-saturated conditions. (C) 1998 Elsevier Science B.V.