In parallel to session BG 7.2 this Splinter Meeting will be hosted by the joint SCOR & InterRidge WG135. An open discussion (17:30-18:30) will anticipate the regular group meeting (19:00-20:00). The aim of the open discussion is to interact with a broad scientific community in view of a future assessment the potential contribution of hydrothermal system to ocean ecosystems and carbon cycle at different scales. At a time when plans for exploration and exploitation of deep-sea mineral resources are rapidly developing, with potential impacts on habitats and biodiversity, there is an urgent need to consider the potential ‘services’ provided by these systems to the ocean related to chemosynthetic biomass production and C-cycling. The discussion aims to create opportunities to bridge scientific efforts focusing on these environments. Programme and session conveners of related EGU themes are encouraged to relay this invitation to participants in their sessions.