Exploring the caves of the remote Selvagens Islands: the Microceno project

Ana Miller, Francesco Sauro

In July 2021, a multidisciplinary speleological expedition to the Selvagens Islands was carried out. This tiny archipelago in Macaronesia, to the south of Madeira, is located within Portuguese territory. The archipelago is renowned as one of the most intact, uncontaminated places in the Atlantic Ocean, frequented in the summer months, as a nesting site, by more than 85,000 birds, mainly of the Cory’s Shearwater species (Puffinus diomedea borealis). Since 1961, the year in which these islands were first included in international maritime cartography, numerous scientific expeditions have studied the flora and fauna there. However, until today, the archipelago had never been investigated in terms of the numerous sea caves, some of which were known about in previous centuries, particularly through stories of legendary hidden treasures, such as that of Captain Kidd, which was enthusiastically sought in the seventeenth century. The Microceno project, financed by the Portuguese Foundation for Technology and Science and co-ordinated by Dr Ana Miller of Evora University, had the objective of enhancing our knowledge of these caves not only in exploratory and documentary terms, but also in terms of their biology, microbiology, geology and analogy with extra-terrestrial environments, given that the volcanic caves in question are similar to those that may, in future, be found on Mars. The expedition involved researchers from a full seven countries (Portugal, Spain, Italy, the Netherlands, the UK, Russia and Canada) in a collective effort that made the most of an innovative technological approach. Indeed, to minimise the environmental impact associated with on-site research, a sophisticated laboratory was set up on the island, including a scanning electron microscope (SEM Phenom made by Thermofisher) and instruments for DNA sequencing