Periphyton is the material consisting primarily of algae found at the bottom of river and lake beds. Healthy rivers depend on periphyton as the base of the food web but high abundance can have negative effects on ecosystem services, human health, economics, recreation, and aesthetics. Mathematical models are used to predict river periphyton responses to perturbations (eg, changes in flow or nutrient loads).
This report reviews how mechanistic (process-based) models simulate periphyton biomass using algorithms describing known growth and loss processes based on nutrients, light, temperature, grazing, and physical factors. The report also provides preliminary guidance for advancing mechanistic river periphyton modelling to inform nation-wide periphyton management in New Zealand.