Scientists developed a new model to predict how much phytoplankton will grow in rivers on an hourly basis. They used this model to study the River Thames in England for two years. The model accurately predicted changes in phytoplankton levels based on factors like water temperature, flow rate, and nutrients. They found that phytoplankton blooms are influenced by how long the water stays in the river, the amount of light it gets, and the temperature of the water. By using the model, scientists can better understand and manage phytoplankton growth in rivers, which can help prevent large blooms from forming.