Geochemical survey of Levante Bay, Vulcano Island (Italy), a natural laboratory for the study of ocean acidification

► We collected a total of 70 water samples in 2011 from a shallow submarine vent area. ► We analysed major, minor elements and dissolved gases. ► pH ranges from 5.64 units to ambient seawater values. ► Dissolved gases are enriched near the bubbling area. ► The CO2 gradient produces saturated conditions at >300 m from the main vent site.