Interest on the potential CO 2 sequestration of marine bivalve aquaculture has increased during the last decade. However, there is still some controversy about which biological processes are involved and how to estimate their contribution to the carbon footprint of bivalve aquaculture. This work considers the dissolved inorganic carbon, CO 2 and alkalinity fluxes linked to flesh and shell growth, calcification, respiration, faeces egestion, and ammonia excretion, accounting also for the RDOC production associated to these processes. We have developed an algorithm for a dynamic estimation of these fluxes based on a net production DEB growth model for mussels. The resulting model has been implemented in Python to create a toolbox with a graphical user interface. This toolbox allows the selection of different culture strategies, in terms of seeding date, seed size and culture length, and consequently analyzes the carbon footprint and impact on the carbonate chemistry of seawater of aquaculture management. • Mussel physiology is commonly ignored in carbon footprint estimates of mussel aquaculture. • MusselCF provides dynamic estimation of mussel culture carbon footprint and its impact on the seawater carbonate chemistry. • Hydrography, carbonate chemistry, seeding time and mussel seed and harvest size dictate the physiological carbon footprint. [ABSTRACT FROM AUTHOR]