A simple tool for the early prediction of the cyanobacteria Nodularia spumigena bloom biomass in the Gulf of Finland

A fuzzy logic model for predicting the maximum biomass of the toxic cyanobacteria Nodularia spumigena bloom in the Gulf of Finland is suggested. The model bloom biomass depends on the phosphate conditions up to 15 June, including the excess phosphate left over after the spring bloom and on the phosphate inputs parameterised by wind mixing and upwelling from 1 May to 15 June. The surface layer temperature, set to vary from 14 to 23◦C, is regarded as a bloom regulating parameter. The model simulations showed that the predicted N. spumigena biomasses differ markedly from year to year and clearly depend on phosphate conditions up to 15 June.