The recent iMAR expedition to the Mid-Atlantic Ridge (MAR) in the Azores region has generated new data that demonstrate the ridge supports more life and diversity than previous studies have indicated. Although the data has yet to be analysed in detail, this expedition yielded some surprising discoveries.
Led by Dr. Telmo Morato and Marina Carreiro-Silva from Okeanos, University of the Azores, the expedition on RV Pelagia (18 May – 2 June 2021) identified new areas that fit the definition of Vulnerable Marine Ecosystems. This valuable new scientific information will inform the development of policies that promote the preservation of natural resources, ensure the sustainable use of the deep sea and minimise negative impacts on these vulnerable ecosystems.
The video work to characterise the benthic communities revealed the largest aggregation of black corals (or black coral gardens) ever seen in the Azores and perhaps across the Atlantic. These corals are very slow growing and can live for several thousands of years and, therefore, the gardens that form can be considered as the equivalent of the redwood forests (oldest trees on the planet) that still persist, for example, in the United States of America.
The team also discovered several areas of deep-sea coral thickets that have an important role as carbon reservoirs and in mitigating climate change. Some of these corals, along with sponges, are habitat structuring species, functioning as refuge areas for other species including commercially important deep-sea fish, and thus enhancing the total biodiversity associated with these habitats. Orange roughy and cardinalfish were observed, confirming that the trawl ban within the Azores EEZ, declared in 2005, has had positive effects for these species and the habitats they are associated with.
Multibeam bathymetric surveys revealed several locations in the northern part of the Azores EEZ that are much shallower than previously thought. One of these areas is shallow enough (less than 600 m) to be at risk from fishing, but thanks to its anonymity it can be considered intact. These areas are fundamental for understanding what ecosystems looked like before they were impacted by fishing activities and may be considered as reference sites and priority areas for conservation.
As well as informing policy development and conservation actions, these new discoveries the data from this expedition will contribute significantly to the Instituto Hidrográfico (IH) programme Mapping the Portuguese Sea, and to the United Nations Decade of Ocean Science for Sustainable Development (2021-2030).
Cruise statistics
13 working days at sea, 2,500 km of transits, 12 areas visited, 5,000 km2 of mapped seabed, 19 dives with the NIOZ video system that resulted in 54 hours of deep-sea images over 48 km of the seabed, 10 stations for the analysis of water mass properties and to collect sediments, which resulted in 360 samples for environmental DNA, 260 samples for nutrient analyses, 27 sediment samples for geological analyses, 24 for microplastic analyses, and 10 samples for bacteriological and meiofauna analyses.
This expedition was funded by the SEA OCEANS program of Eurofleets+ and the European project iAtlantic, was led by IMAR and Okeanos from the University of the Azores (Portugal) in collaboration with the Hydrographic Institute and University of Porto (Portugal), the University of Aarhus (Denmark), the National Oceanography Center (United Kingdom), GEOMAR (Germany), the University Museum of Bergen (Norway), the PP Shirshov Institute of Oceanology (Russia), and the University of Vale do Itajaí (Brazil).
