Growth of Cyclotella meneghiniana Kutz. II. Growth and cell composition under different growth rates with different limiting nutrient

The growth and cell composition of C. meneghiniana in P-, N- or Si-limited continuous cultures under different dilutions are discussed. Carbon, nitrogen and phosphorus content per cell or per unit cell volume increased with growth rate in all chemostats. Maximum growth rate depends on the type of limiting nutrient. The maximum growth rates are 1.65 +/- 0.04, 0.73 +/- 0.07 and 0.95 +/- 0.08 d(-1) for P-, N- and Si-limited cultures respectively. These values are close to those calculated by Droop, Caperon, Goldman and Monod models. The concentrations of N and P in the river Danube are much higher than the requirements for growth and uptake of C. meneghiniana. This indicates that neither P nor N are limiting to the growth of C. meneghiniana in natural habitat.