A mass-balance model for phosphorus in lakes accounting for biouptake and retention in biota

1. A new mass-balance model was developed to predict phosphorus fluxes to, within and from lakes and lake concentrations of phosphorus. 2. The model is driven by data easily accessed from standard monitoring programmes or maps, so it should be useful in many contexts of lake management. 3. The phosphorus model gives seasonal (weekly) variations and accounts for all fundamental abiotic/biotic interactions and feedbacks for lakes in general for phosphorus. The model has been developed within the framework of a more comprehensive ecosystem model, LakeWeb, which accounts for production values and biomasses of nine functional groups of organisms (phytoplankton, bacterioplankton, herbivorous and predatory zooplankton, prey and predatory fish, zoobenthos, macrophytes and benthic algae). 4. The LakeWeb-model has been critically tested in a wide limnological domain and shown to predict very well. By using this model, it is possible for the first time to predict realistic values of biouptake and retention of phosphorous in biota in lakes on a weekly basis.