Modelling the influence of silicon and phosphorus limitation on the growth and toxicity of Pseudo-nitzschia seriata

Pseudo-nitzschia seriata (Cleve) H. Peragallo isolated from Scottish west coast waters was studied in laboratory batch culture. The neurotoxin domoic acid was produced in both P- and Si-limited stationary phase, but in greater quantities when Si was the limiting nutrient. A mathematical model based on cell quota kinetics was used to simulate P. seriata growth and toxin production. The model was capable of simulating changes in cell density and carbon biomass in the independent Si- and P-limited experiments using a single parameter set. In the model, toxin production was related to C cell(-1) and triggered by nutrient stress, defined by low values of the carbon-based cell quota of the limiting nutrient. The study therefore suggests that simple models, based on easily measured quantities, are capable of simulating Pseudo-nitzschia growth and toxin production.