Multidisciplinary Scientific Cruise to the Northern Mid-Atlantic Ridge and Azores Archipelago

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

Drifting in the deep: Metatranscriptomics and metabarcoding reveal sustained metabolic activity and community composition in hydrothermal vent plume microbial communities

“…In 2011, further surveying with CTD tow-yos and ROV missions led to the discovery of the Moytirra hydrothermal vent system (Wheeler et al, 2013). Two published expeditions have visited the site, providing high-resolution mapping and characterizing the geology and animal fauna (Wheeler et al, 2013;Somoza et al, 2020). Located at 45°N, this high-temperature vent field is basalt-hosted, consisting of multiple black smokers and sitting midway up the 300 m high fault scarp of the eastern axial wall, 3.5 km from the axial volcanic ridge crust at ~2900 m depth (Wheeler et al, 2013).…”

Fluid chemistry alters faunal trophodynamics but not composition on the deep-sea Capelinhos hydrothermal edifice (Lucky Strike vent field, Mid-Atlantic Ridge)

“…Capelinhos is located ~ 1.5 km to the east of the main Lucky Strike (LS) area (nMAR) at 1665 m depth (37.28917 N, − 32.26388 E) 52 (Fig. 1 A) (not to be confused with the Capelinhos volcano on the Faial Island, Azores Archipelago 77 ). The LS hydrothermal vent field (~ 1700 m depth), discovered in 1992, is located on the Lucky Strike Seamount on the Azores Triple Junction 61 , 78 .…”

The Interactive Role of Hydrocarbon Seeps, Hydrothermal Vents and Intermediate Antarctic/Mediterranean Water Masses on the Distribution of Some Vulnerable Deep-Sea Habitats in Mid Latitude NE Atlantic Ocean

“…Therefore, within the Macaronesia volcanic archipelagos, several recent submarine eruptions have taken place in Capelinhos (west Faial Island, Azores) in 1958-59 or south of El Hierro Island (Canary Islands) in 2011-2012 [34]. The recent discovery of soft coral gardens dominated by Alcyonacea in the Azores Archipelago [90] colonizing the volcanic substrate created from the eruption of Capelinhos in 19581-959, opens new studies of succession and survivorship of habitat-forming species in the Macaronesia volcanic areas as they have already been developed in the Hawaiian Islands [91].…”