As well as warming the oceans, CO2 released due to human activities is also causing ocean acidification, which alters the fundamental chemical balance of surface waters (e.g. reducing the amount of carbonate). Our laboratory uses natural analogues of ocean acidification (CO2 seep) in Japan and Europe alongside manipulative experiments to understand the eco-physiological processes involved in the response of winner and loser species to ocean acidification and warming in Japan and on coastal ecosystems worldwide. We mostly focus on marine macrophytes as they are key organisms for the structure and functioning of coastal ecosystems. The aim will be to improve the knowledge on the impacts of combined ocean acidification and global warming on the fate of their distribution and the associated ecosystem services.