Megafaunal assemblages in deep-sea ecosystems of the Gulf of Cadiz, northeast Atlantic ocean

Jordi Grinyó (1, 2) , Marco Francescangeli , Andreu Santín (1) , Gemma Ercilla (3) , Ferran Estrada (4) , Ariadna Mecho (5, 6) , Emanuela Fanelli (7) , Corrado Costa (8) , Roberto Danovaro (9) , Joan Batista Company (1) , Ignacio Sobrino (10) , Javier Valencia (11) , Jacopo Aguzzi (1, 9)

1 ICM - Institute of Marine Sciences / Institut de Ciències del Mar [Barcelona]
2 NIOZ - Royal Netherlands Institute for Sea Research
3 ICM - Instituto de Ciencias del Mar de Barcelona
4 UB - Universitat de Barcelona
5 LSCE - Laboratoire des Sciences du Climat et de l'Environnement [Gif-sur-Yvette]
6 MERMAID - Modelling the Earth Response to Multiple Anthropogenic Interactions and Dynamics
7 UNIVPM - Polytechnic University of Marche [Ancona, Italy] / Università Politecnica delle Marche [Ancona, Italia]
8 CREA - Consiglio per la Ricerca in Agricoltura e l’analisi dell’economia agraria = Council for Agricultural Research and Economics
9 SZN - Stazione Zoologica Anton Dohrn
10 IEO - Instituto Espagňol de Oceanografia
11 Chercheur indépendant

Deep-sea ecosystems of the Iberian margin have been widely impacted over the past decades, but the limited knowledge on their biodiversity and functioning limits our ability to contribute to their conservation. So far, in the Gulf of Cadiz, research has mostly been focused on megabenthic assemblages associated to mud volcanoes. However, several other geomorphological structures have remained widely unexplored. Here, by means of a quantitative analysis of 17 video transects conducted between 220 and 980 m depth, we investigated megabenthic assemblages associated to canyons, contouritic channels, contouritic furrows and open slopes. We report the presence of 8 different assemblages, segregated as a result of the different substrates and geomorphologic features. Megabenthic assemblages on hard substrates were characterized by mono or multispecific sponge assemblages. Soft bottoms hosted crinoid beds, pennatulacean meadows and fields of the gorgonian Radicipes gracilis. These results highlight the high diversity of megabenthic assemblages in deep-sea ecosystems of the Gulf of Cadiz and suggest that most of the geomorphological features that remained so far unexplored represent vulnerable marine ecosystems deserving protection and inclusion in future management plans.

Mots clés: Benthic assemblages; Deep-sea ecosystems; Gulf of Cadiz; Vulnerable marine ecosystems; ROV imaging

Domaines: Sciences du Vivant [q-bio]; Sciences de l'environnement

Jordi Grinyó, Marco Francescangeli, Andreu Santín, Gemma Ercilla, Ferran Estrada, et al.. Megafaunal assemblages in deep-sea ecosystems of the Gulf of Cadiz, northeast Atlantic ocean. Deep Sea Research Part I: Oceanographic Research Papers, 2022, 183, pp.103738. ⟨10.1016/j.dsr.2022.103738⟩. ⟨hal-04430221⟩