Luso hydrothermal vent field. © ROV Luso, Portuguese Task Force for the Extension of the Continental Shelf

Luso was discovered during an ATLAS/Oceano Azul/MapGES expedition on June 16th 2018 on the slopes of Gigante, a seamount on the Mid-Atlantic Ridge (MAR) in the seas of the Azores. The hydrothermal vent Luso is composed of multiple chimney-like structures with orifices up to approximately 40cm in diameter. This system differs considerably from other known hydrothermal fields along the MAR in terms of fluid chemistry with dominance of hydrogen and iron, and low temperature. These elements support diverse chemoautotrophic microbial communities and benthic fauna, with several putative new species to science. The diffuse fluid emission released by this type of hydrothermal system may represent an important but overlooked source of iron to the oceans, an essential element to primary productivity, thus playing a potentially important role as “fertilisers” of oligotrophic oceanic systems such as those in the Azores. This new exciting discovery is special in that it is located in an important fishing ground, close to the shores of the Azores. This highlights how little we know about the deep sea, even when the deep sea is right in our back yard. At a time when the United Nations is developing a new international agreement on the conservation and sustainable use of biodiversity in areas beyond national jurisdiction (BBNJ), it would be contradictory for individual countries not to develop science-based management strategies for deep-sea exploration within their own territorial waters.