Modelling CO2 budget of mussel farms across the Mediterranean Sea.

The role of bivalve aquaculture as a carbon sink is highly debated, without a general consensus on the components to include in the budget. This study proposes to estimate the terms of the budget using a scope-for-growth-based model. The model was applied at 12 Mediterranean sites, with environmental forcings provided by operational oceanography data spanning over 12 years. Mussels were found to be slight sinks, with a limited variability across sites, if all components of the budget, i.e. accumulation in soft tissue, emissions associated with calcification and respiration, are included. The differences found among stations concerning the calcification and soft tissue contributions to the budget were found to be related to site-specific productivity and water chemistry parameters. This led to the identification of a set of meta-models, which could be used for relating the budget to local conditions, at a screening level, rendering them useful for optimal site selection.