Three-Dimensional Modelling of a Microcystis bloom event in a Western Australian Estuary

In January 2000, there was a record maximum rainfall throughout much of the watershed of the Swan River estuary, leading to the first reported Microcystis aeruginosa bloom in the estuary. Peak cell counts reached over 100,000 cells mL-1. A coupled three-dimensional hydrodynamic-ecological model, ELCOM-CAEDYM, is applied to the period of development and subsequent decline of the bloom. The model, previously calibrated for a more typical year (1995), accurately reproduced the unusual hydrodynamic circumstances and predicted the magnitude and timing of the Microcystis bloom. Salinity and temperature were the primary factors controlling the growth of Microcystis during the period of interest. The simulations described provide further validation of the model and its potential as a predictive tool.