Hydrothermal systems in the deep ocean have been studied from the past 37 years, but their impact on the ocean biogeochemistry and related ecological processes is far from being understood. Vent ecosystems were long described as largely independent from the photosynthesis-driven biosphere, a paradigm which no longer stands. Today we have a slightly clearer picture of the role energy transfer from hydrothermal circulation could play on ecosystems across a range of depths and on subseafloor carbon sequestration. At a time the exploration and exploitation of deep-sea mineral resources is rapidly developing, with potential impacts to habitats and biodiversity, there is a urgent need to consider the potential ‘services’ that is provided by these systems to the ocean.

The aim of this session is to synthesize the most advanced knowledge on:
1) carbon-fixation pathways in the different compartments influenced by hydrothermal activity, the metabolic diversity sustaining them and their dependence on oceanic processes,
2) biotic and abiotic drivers of productivity of related seafloor and subseafloor ecosystems, their natural dynamics and sensitivity to disturbance,
3) hydrothermally-derived fluxes of micronutrients and exported DOC and their potential influence on ocean biogeochemistry at larger scale.
4) integration of these processes into conceptual models of energy transfer and carbon cycling.

Our objective is also to enlarge the discussion outside the field of vent research with a broader scientific community and determine the opportunities to bridge scientific efforts focussing on these environments with larger marine science programmes in view of a future assessment the potential contribution that they may make to the ocean ecosystems and carbon cycle at different scales.
This session is organized as part of the InterRidge and SCOR WG135 working group activities.