Groundwater discharge and submarine geothermal phenomena

The submarine or coastal groundwater outflow is often due or overlapped to important offshore geothermal phenomena, which contribute to modify geochemical water characteristics, sometime adding relevant gases outflow fractions. The peculiarities of these natural phenomena create uncommon difficulties to the geological, geochemical, and hydrogeological conceptualization, the solution of which contributes to the earth knowledge, in some cases, at high depth. The study of these phenomena, call for a continuous improving of study tools, methods and equipment. The peculiarities of these fluid outflows can create peculiar environment, of high ecological relevance and/or with important social and economic effects, also in terms of any type of geothermal energy utilisation. The special issue is a global call for any experience of scientific relevance which is facing with the study of these phenomena from any point of view, including methodological or technological improvements, or to focus on conceptualization of peculiar study cases, and review articles which describe the current state of the art on these subjects.