Beyond the hydrothermal vents: Megafauna of the Mid-Atlantic Ridge

In the French exploration area for Seafloor Massive Sulfides, two cruises with the HOV Nautile and one cruise with the ROV Victor 6000 have been carried out in 2014, 2017 and 2018. The BICOSE1 cruise (2014) and Bicose2 cruise (2018) focused on the two vent fields TAG and Snake Pit while during the HERMINE cruise (2017), the exploration contract was explored from south (21°N) to North (26°N). The megafauna and geomorphological have been annotated from HOV- and ROV-videos. The seafloor is dominated by hard substrates, mainly basalts, locally interspaced by patches of soft-sediments. Most the dives were carried out at depth deeper than 3000 m. At those depths, and beyond the influence of hydrothermal vents, which gradually decreases within a hundred meter of the most active sites, the megafauna is sparse but yet diverse. On a seamount reaching 1200 m depth however, an unusual ground of a yet unknown sponge have been observed. At first glance, the sponge can be easily be confounded with an octocoral. This large branched sponge differs from Sarostegia oculuta but similarly mimics coral gardens.

How to cite
Menot Lenaick, Planchette Fanny (2018). Beyond the hydrothermal vents: Megafauna of the Mid-Atlantic Ridge. DSBS 2018 - 15th Deep-Sea Biology Symposium. 09 au 14/09/2018, Monterey (Californie).

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