Understanding is currently limited of the biological processes underlying the responses of modular organisms to climate change and the potential to adapt through morphological plasticity related to their modularity. Here, Lombardi and coauthors investigate the effects of ocean acidification and seawater warming on the growth, life history and morphological plasticity in the modular bryozoan Calpensia nobilis using transplantation experiments in a shallow Mediterranean volcanic CO2 vents system that simulates pH values expected for the year 2100. Growth models describing colony development under different environmental scenarios suggest that stressed colonies of C. nobilis reallocate metabolic energy to the consolidation and strengthening of existing zooids. This is interpreted as a change in life-history strategy to support persistence under unfavourable environmental conditions. Changes in the skeletal morphology of zooids evident in C. nobilis during short-time exposure experiments reveal morphological plasticity that may indicate a potential to adapt to the more acidic Mediterranean predicted for the future.