Hydrothermal processes

Submarine hydrothermal activity was detected only toward the latter part of the 20th Century as a direct – but largely unanticipated – consequence of the Plate Tectonics Revolution. It has now been shown to occur in every ocean basin of our planet and to have profound impacts on ocean biogeochemical cycles. In the past decade, one particularly important advance has been the realization that we have not yet identified the full spectrum of geologic settings in which submarine venting can occur; hence, we have not yet characterized the full range of geochemical fluxes that can arise from hydrothermal circulation in the sub-seafloor. A further important discovery is that the release of trace elements and isotopes may be intimately associated with the global carbon cycle, not just at the deep seafloor but up to and including sequestration of significant amounts of carbon at the air-sea interface: in High Nutrient Low Chlorophyll (HNLC) regions at high latitudes, hydrothermally-sourced Fe may provide a previously unrecognized source of essential micronutrients to sustain primary productivity. Finally, the last decade has revealed the presence of multiple additional ocean worlds within our solar system, at least some of which have the capacity to host – and even have already revealed evidence for – styles of submarine venting that could support abiotic organic synthesis and, potentially, be inhabited.