In shallow or deep water, in lakes, oceans and seas, in high-resolution single channel or industrial 3D data, gas systems are visible in the deep seismic record, in the shallow subsurface and escaping from the seafloor. Often, this gas can reach the atmosphere, providing an accounted for contribution to global warming. This course, which is open only to students of the Laboratory for Applied Geophysics, tackles this topic from multiple directions and aims at providing students with knowledge of this topic which is at the forefront of marine research.