Total CO₂ output from Vulcano island (Aeolian Islands, Italy)

Total CO 2 output from fumaroles, soil gas, bubbling gas discharges and water dissolved gases discharged from the island, was estimated for Vulcano island, Italy. The CO 2 emission from fumaroles from the La Fossa summit crater was estimated from the SO 2 crater output, while CO 2 discharged through diffuse soil emission was quantified on the basis of 730 measurements of CO 2 fluxes from the soil of the island, performed by using the accumulation chamber method. The results indicate an overall output of ≅500 t day −1 of CO 2 from the island. The main contribution to the total CO 2 output comes from the summit area of the La Fossa cone (453 t day −1 ), with 362 t day −1 from crater fumaroles and 91 t day −1 from crater soil degassing. The release of CO 2 from peripheral areas is ≅20 t day −1 by soil degassing (Palizzi and Istmo areas mainly), an amount comparable to both the contribution of water dissolved CO 2 (6 t day −1 ), as well as to seawater bubbling CO 2 (4 t day −1 measured in the Istmo area). Presented data (September 2007) refer to a period of moderate solphataric activity, when the fumaroles temperature were 450°C and gas/water molar ratio of fumaroles was up to 0.16. The calculated total CO 2 emission allows the estimation of the mass release and related thermal energy from the volcanic‐hydrothermal system.