Developed by combining components simplified from previously developed mechanistic models, acomplete dynamic model is described for simulating the growth of phytoplankton as functions of ammonium, nitrate, light, iron, silicon, phosphorus and temperature. Components may be safely added or deleted to the base model, describing ammonium–nitrate–light interactions, to suit particular modelling scenarios. Biomass is described in terms of C and cells, while chlorophyll is also a state variable enabling the simulation of changes in Chl a:C with photoacclimation. The model is capable of simulating variable silicon deposition (diatoms) and C cell–1 with Si, Fe, or P limitations. Mechanisms for inclusion of temperature control of nutrient transport, growth rate and cell size are given. The model is suitable for placement in ecosystem models, containing various components that can be readily modified to tune the simulation to mimic the behaviour of specific algal groups or species. Most of those components have biological significance and can be estimated from experiments or by analysis of existing data.