The course provides advanced knowledge on the cycle of volatiles (in particular carbon and light noble gases) in the Earth's interior, in relation to geodynamics, volcanism and climate change. PhD students, through a multidisciplinary approach, learn the use of geochemical tracers (particularly isotopic ratios) in mantle and magmatic environments to constrain the origin of fluids. Attention will also be posed to the potential impact of magmatic/hydrothermal degassing on submarine ecosystems. There will be discussed some study cases representative of how volatiles isotopic signatures change in relation to i) terrestrial geodynamics, ii) the recycling of crustal material into the mantle, iii) the effect of magmatic degassing at mantle and crustal depths.