THE EFFECTS OF A CONTROLLED FLUCTUATING NUTRIENT ENVIRONMENT ON CONTINUOUS CULTURES OF PHYTOPLANKTON MONITORED BY COMPUTERS

A completely automatic continuous phytoplankton culturing device is de scribed. This computer-controlled system monitors simultaneously and a utomatically the basic culture parameters of several chemostats, i.e., limiting nutrient concentrations, cell size spectra, cell densities a nd temperatures. Culture pH can also be regulated. The dilution rate a nd the limiting nutrient concentration in the enrichment medium may be programmed to follow different dynamic patterns with time. An example is given with a sinusoidal variation of the dilution rate. Applicatio ns are discussed, which concern the advantages to modelling gained by acquiring information from continuously fluctuating systems rather tha n from nutrient-pulsed systems.