Deep-sea hydrothermal vent fields were recently discovery. The first one was observed in 1977 during an expedition at the oceanic spreading ridge near the Galapagos Islands (Corliss et al., 1979). In this cruise scientist were using the submersible Alvin when they made a stunning discovery on the bottom of the Pacific Ocean – they observed hot and drack mineral-rich fluids venting from the seafloor. This discovery did not only reveal hydrothermal fluid emanating through vents hosted at the seafloor (black smokers), but it also presented to the scientific community never before seen organisms living around these hot, toxic and lightless environments, using sulphur-oxidizing bacteria to derive their entire energy.

Deep-sea hydrothermal vents are usually formed in volcanically active areas on mid-ocean ridges. In these sites seawater percolating down through ocean crust through fissures, cracks and porous rocks and is heated by a heat source (frequently magmatic). The heat helps drive chemical reactions that remove O, Mg, sulfates and other chemicals from the seawater and fluids become hotter and more acidic, causing them to leach metals such as Fe, Zn, Co, Pb, Co etc from the rocks that are percolated by this fluids. In some circumstances also Au and Pb are also leached. The heated fluids rise back to the surface through openings in the seafloor. Hydrothermal fluid temperatures can reach very high temperatures as 300-400°C and when these hot fluids are enriched in metals they became dark (Black smokers). Most of the known hydrothermal fields are located at very high depths, most of them higher than 1000m depth (Lucky strike for example is located at higher than 1600m). The hot vent fluids cause them to be more buoyant than ocean water however, at these depths; they do not boil because they are under the extreme pressure of the deep ocean.

The world’s deepest hydrothermal vent field known, until now, is located in the Cayman Trough at 5000 m deep (discovery in 2010: Connelly et al, 2012). Watch the video of these expedition here: Missions to Cayman Trough deep-sea vents

ISE is involved in the Blue Mining Project. The overall objective of Blue Mining is to provide breakthrough solutions for a sustainable deep sea mining value chain. This means to develop the technical capabilities to adequately and cost-effectively discover, assess and extract deep sea mineral deposits up to 6,000 m water depths as this is the required range where valuable seafloor mineral resources are found. On 25 of May we stared a new RESEARCH CRUISE (Cruise M127): to see the news go to: BLOG from the RESEARCH CRUISE M127