Modelling lake cyanobacterial blooms: Disentangling the climate-driven impacts of changing mixed depth and water temperature

Abstract

1. Climate change is already having profound impacts upon the state and dynamics of lake ecosystems globally. A specific concern is that climate change will continue to promote the growth of phytoplankton, particularly blooms of toxic cyanobacteria, via lake physical processes including warming surface waters and shallowing of the mixed layer. These two mechanisms will have different impacts on lake phytoplankton communities, but their inter‐connectedness has made it difficult to disentangle their independent effects. 2. We fill this knowledge gap by performing 1666 numerical modelling experiments with the phytoplankton community model, PROTECH, in which we separated the independent effects on lake phytoplankton of temperature change and changes in the depth of the surface mixed layer. Given the large global abundance of small lakes (