Modelling (Nuisance) Algal Physiology

K.J.Flynn
Ecology Research Unit,
Wallace Building,
University of Wales Swansea,
SA2 8PP, UK

A comparative overview will be given of the range of models available for simulating the growth of microalgae, balancing the needs for simplicity versus realism. With the appreciation of the true complexity of algal ecophysiology, multi-nutrient models are required. However, simple models for the description of multi-nutrient interactions may contain constructional errors that invalidate their output. If the construction is inadequate, although growth may be correctly simulated, the removal of lesser-limiting nutrients (the availability of which affects subsequent generations) is prone to serious errors. A simplified model for ammonium-nitrate-P-Si-Fe-light interactions has been developed that offers a suitable compromise for placement in ecosystem simulators. As an example of the utility of multi-nutrient algal models, the results of simulations in which a detailed model of N-P interactions in PSP producing Alexandrium is run within a vertical water structure (allowing DVM) will be shown. This predicts that highly toxic cells may grow at even moderately elevated N:P.