  A numerical model for mixotrophic phytoplankton is described in this paper.
In contrast with traditional approach where nutrient uptake rates are
constrained by a predefined growth rate, this model uses empirical traits to
compute nutrient uptake rates, and then the growth is controlled by the
nutrient uptake. Simple but meaningful traits for heterotrophy are derived by
analogising heterotrophic mode with phototrophic mode. The trait-based approach
could reduce the model parameterization significantly. Model performance
evaluation against laboratory experiments of various phytoplankton species has
shown remarkable successfulness. Using a single set of model parameterization,
the model is able to capture well the growth rate, nutrient consumption,
accumulation of none-limiting nutrients, increase of cell size of
nutrient-starved cells, surge uptake and rapid population growth of starved
cells when nutrient is added as well as the mixotrophic interaction of
different pairs of predator-prey. The model for mixotrophic phytoplankton is
couped with a hydrodynamic model to simulate algal blooms in Singapore water.
The model has shown a great potential for practical applications
