Flux measurements of nonvolcanic CO2 emission from some vents in central Italy

In central Italy, nonvolcanic CO2 is discharged from many areas of focused degassing (vents and associated strong diffuse emission) and from high-pCO(2) groundwater. We estimate that there are at least 100 CO2 vents in central Italy, many of which have a history of lethality to animals and humans. The gas vents are extremely efficient pathways for transporting large amounts of deeply derived CO2 from gas reservoirs to the surface. As CO2 fluxes from these vents were heretofore unmeasured, several complementary methods were developed to measure the CO2 flux from seven of these vents, which cumulatively discharge 3.1x10(9) mol yr(-1) CO2(472 t d(-1)). Considering all of the vents in central Italy, the total CO2 flux from vents alone may be similar to the CO2 emission from the Taupo Volcanic Zone in New Zealand (similar to 10(10) mol yr(-1); similar to 1200 t d(-1)) and other areas of high heat flow. Summing the CO2 discharged from vents, areas of diffuse CO2 degassing, and degassing of high-pCO(2) groundwater, we provisionally estimate that the total nonvolcanic CO2 flux to the atmosphere in central Italy may be >10(11) mol yr(-1) (similar to 12,000 t d(-1)).