Abstract. Marine calcifiers as a plankton functional type (PFT) are a crucial part of the global carbon cycle, being responsible for much of the carbon export to the deep ocean entering via biological pathways. Deep ocean carbon export through calcifiers is controlled by physiological, ecological and biogeochemical factors. This paper describes the implementation of a phytoplankton coccolithophore PFT in the University of Victoria Earth System Climate Model (UVic ESCM), and improvements to the representation of zooplankton calcification and carbon export therein. The described modifications improve model performance with respect to carbon and nutrient fluxes. Primary production, export production, particulate organic carbon and calcite fluxes all fall within independent estimates.