Abstract
This work presents the preliminary result of the multidisciplinary cruise EXPLOSEA2 surveying the northern Mid-Atlantic Ridge and Azores Archipelago from 46° 30′ N to 38° 30′ N aboard the R/V Sarmiento de Gamboa and ROV Luso over 54 days (June 11 to July 27, 2019). In this cruise report, we detail the geophysical, hydrographic, geological, oceanographic, ecological, and microbiological data acquired and a brief of main findings. The cruise addressed the exploration and comprehensive characterization of venting sites, including the water column, the sediments and rocks that host the hydrothermal activity, and the associated mineralizations, biology, and microbiology. Deep hydrothermal chimneys and massive sulfide deposits (up 3,000 m in depth) within the Moytirra hydrothermal active field were identified on slopes that had not been explored previously. Another striking finding made during the EXPLOSEA2 cruise was the field of carbonate chimneys named the “Magallanes-Elcano” field, a potentially relict ultramafic-hosted hydrothermal site sourced by abiotic methane. This field is related to a serpentinite and gabbro rock outcropping on a dome-shaped massif named the “Iberian Massif.” An outstanding finding of the EXPLOSEA2 survey was the identification of the first garden of soft corals growing after active submarine eruptions were reported in the Azores Archipelago composed by a high density of soft corals the suborder Alcyoniina at the summit and flanks of a recent volcanic cone at 160 m water depth developed during the 1957–1958 eruption of Capelinhos. Several cold-water coral habitats formed by colonial scleractinians (e.g., Lophelia pertusa and Madrepora oculata), coral gardens composed of mixed assemblages of black corals (Leiopathes sp.), and octocorals and dense aggregations of the glass sponge Pheronema carpenteri that may be classified as vulnerable marine ecosystems (VMEs) have been discovered during the EXPLOSEA2 cruise along the northern Mid-Atlantic Ridge. This work reveals the importance of multidisciplinary surveys to the knowledge of deep-sea environments.
Highlights
The high-resolution mapping of the seabed and habitat of the entire North Atlantic Ocean is a challenge that must be overcome to augment our present knowledge of the Atlantic seabed
regional environmental management plan (REMP) have been interpreted as essential tools because they provide regional-specific information that facilitates the decision-making for present exploration and future exploitation of mineral resources in order to ensure the effective protection of the marine environment according to Article 145 of the United Nations Convention on the Law of the Sea (UNCLOS)
Between the South Azores Fault at ∼ 38◦ 20 N and the Charlie-Gibbs Fracture Zone at 52◦ 25 N, only two active hydrothermal vents with associated mineral deposits have been reported: (1) The Moytirra field at ∼ 45◦ N, a deep-sea, high-temperature vent field with active black smokers discovered on the terraces of the axial valley (Wheeler et al, 2013); and (2) the Luso hydrothermal vent, a shallow low-temperature hydrothermal field, which was recently discovered at the Azores latitude and is associated with the Faial transform fault crossing the MAR3
Summary
The high-resolution mapping of the seabed and habitat of the entire North Atlantic Ocean is a challenge that must be overcome to augment our present knowledge of the Atlantic seabed. It is being addressed by the Atlantic Seabed Mapping International Working Group (ASMIWG) as part of the Trilateral Galway Statement agreement between the United States, European Union, and Canada for the Atlantic Ocean Research Alliance (AORA1). In preparing the North Atlantic REMP, the procedure should involve the use of an extensive multidisciplinary scientific dataset including information such as high-resolution bathymetry mapping, habitat types, biodiversity, active vents, and distribution of massive sulfide mineralizations as essential tools for ensuring the effective protection of the marine environment. Between the South Azores Fault at ∼ 38◦ 20 N and the Charlie-Gibbs Fracture Zone at 52◦ 25 N, only two active hydrothermal vents with associated mineral deposits have been reported: (1) The Moytirra field at ∼ 45◦ N, a deep-sea, high-temperature vent field with active black smokers discovered on the terraces of the axial valley (Wheeler et al, 2013); and (2) the Luso hydrothermal vent, a shallow low-temperature hydrothermal field, which was recently discovered at the Azores latitude and is associated with the Faial transform fault crossing the MAR3
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
