My main research is focused on the origin and seepage of hydrocarbons (seeps, mud volcanoes, microseepage) with implications on petroleum exploration (assessment of petroleum systems, source rocks, oil biodegradation, secondary alterations, reservoir compartmentalization), environment (groundwater and soil pollution, geo-hazards) and global changes (atmospheric greenhouse gas budget). I worked in the framework of EU research programmes on gas migration, radioactive waste management, and development of submarine observatories. Recent studies are focused on the abiotic origin of gas on Earth and Mars, with reference to low temperature abiotic synthesis of methane in ultramafic rocks. I worked in NATO (North Atlantic Treaty Organization) projects, which provided the first data on methane flux from mud volcanoes. Successive studies on gas seepage have provided the first global estimates of geo-methane emissions into the atmosphere, today endorsed in greenhouse-gas emission inventories of the Environmental European Agency, the US EPA and the IPCC. Research is based on collaborations with the Deep Carbon Observatory (Sloan Foundation), NASA, NOAA and several universities and research centres in North America, Europe and Asia.