Location, flow–rate, extension of the hydrogeological basin, chemical and isotopic analyses of the 160 springs considered in this study, along with the results of the carbon mass balance. <i>Measuring and interpreting CO₂ fluxes at regional scale: the case of Apennines, Italy</i>

Tectonically active regions are often characterized by a large amounts of carbon dioxide degassing, and estimation of the total CO₂ discharged to the atmosphere from tectonic structures, hydrothermal systems and inactive volcanic areas is crucial for the definition of present-day global Earth degassing. The carbon balance of regional aquifers is a powerful tool to quantify the diffuse degassing of deep inorganic carbon sources because the method integrates the CO₂ flux over large areas. Its application to peninsular Italy shows that the region is characterized by specific CO₂ fluxes higher than the baseline determined for the geothermal regions of the world, and that the amount of endogenous CO₂ discharged through diffuse regional degassing (~2.1×1011 mol yr^-1) is the major component of the geological CO₂ budget of Italy, definitely prevailing over the CO₂ discharged by Italian active volcanoes and volcanoes in hydrothermal activity. Furthermore, the positive correlation between geothermal heat and deep CO₂ dissolved in the groundwater of central Italy suggests that (i) the geothermal heat is transported into the aquifers by the same hot CO₂ rich fluids causing the Italian CO₂ anomaly and (ii) the advective heat flow is the dominant form of heat transfer of the region.构造活动区通常以大规模二氧化碳(CO₂)脱气为典型特征，而估算从构造结构、热液系统及休眠火山区域排放至大气的总CO₂量，对于界定当前全球地球脱气总量至关重要。区域含水层的碳平衡是量化深部无机碳源弥散脱气的有效手段，该方法可整合大尺度范围内的CO₂通量。将其应用于意大利半岛的研究显示，该区域的CO₂通量显著高于全球地热区域的基准水平，且通过区域弥散脱气排放的内生CO₂总量（约2.1×10¹¹ mol yr⁻¹）构成意大利地质CO₂收支的主要组成部分，远超意大利活火山及热液活动火山所排放的CO₂量。此外，意大利中部地下水中溶解的深部CO₂与地热热量呈正相关，这表明：(i) 地热热量由引发意大利CO₂异常的同一富CO₂热流体输送至含水层；(ii) 对流热流是该区域主要的热传递形式。