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Auteur (up) Arnaud-Haond, S.; van den Beld, I.M.J.; Becheler, R.; Orejas, C.; Menot, L.; Frank, N.; Grehan, A.; Bourillet, J.F. doi  openurl
  Titre Two “pillars” of cold-water coral reefs along Atlantic European margins: Prevalent association of Madrepora oculata with Lophelia pertusa, from reef to colony scale Type Article scientifique
  Année 2017 Publication Revue Abrégée Deep-Sea Res. Part II-Top. Stud. Oceanogr.  
  Volume 145 Numéro Pages 110-119  
  Mots-Clés community; bay; Bay of Biscay; Lophelia pertusa; Madrepora oculata; biscay; mediterranean sea; Cold water corals (CWC); deep-sea corals; False-chimaera colonies; fleuve manche; hydrodynamics; Iceland; Ireland; megafauna; mid-norway; ne atlantic  
  Résumé The scleractinian coral Lophelia pertusa has been the focus of deep-sea research since the recognition of the vast extent of coral reefs in North Atlantic waters two decades ago, long after their existence was mentioned by fishermen. These reefs where shown to provide habitat, concentrate biomass and act as feeding or nursery grounds for many species, including those targeted by commercial fisheries. Thus, the attention given to this cold-water coral (CWC) species from researchers and the wider public has increased. Consequently, new research programs triggered research to determine the full extent of the corals geographic distribution and ecological dynamics of “Lophelia reefs”. The present study is based on a systematic standardised sampling design to analyze the distribution and coverage of CWC reefs along European margins from the Bay of Biscay to Iceland. Based on Remotely Operated Vehicle (ROV) image analysis, we report an almost systematic occurrence of Madrepora oculata in association with L. pertusa with similar abundances of both species within explored reefs, despite a tendency of increased abundance of L. pertusa compared to M. oculata toward higher latitudes. This systematic association occasionally reached the colony scale, with “twin” colonies of both species often observed growing next to each other when isolated structures were occurring offireefs. Finally, several “false chimaera” were observed within reefs, confirming that colonial structures can be “coral bushes” formed by an accumulation of multiple colonies even at the inter-specific scale, with no need for self-recognition mechanisms. Thus, we underline the importance of the hitherto underexplored M. oculata in the Eastern Atlantic, reestablishing a more balanced view that both species and their yet unknown interactions are required to better elucidate the ecology, dynamics and fate of European CWC reefs in a changing environment.  
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  ISSN 0967-0645 ISBN Médium  
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Auteur (up) Becheler, R.; Cassone, A.-L.; Noel, P.; Mouchel, O.; Morrison, C.L.; Arnaud-Haond, S. doi  openurl
  Titre Low incidence of clonality in cold water corals revealed through the novel use of a standardized protocol adapted to deep sea sampling Type Article scientifique
  Année 2017 Publication Revue Abrégée Deep-Sea Res. Part II-Top. Stud. Oceanogr.  
  Volume 145 Numéro Pages 120-130  
  Mots-Clés diversity; dispersal; disturbance; Lophelia pertusa; Madrepora oculata; organisms; population-structure; asexual reproduction; Clonality; Cold-water coral; Fine-grained spatial genetic structure; gorgonian coral; lophelia-pertusa; pertusa linnaeus 1758; spatial genetic-structure; Standardized sampling  
  Résumé Sampling in the deep sea is a technical challenge, which has hindered the acquisition of robust datasets that are necessary to determine the fine-grained biological patterns and processes that may shape genetic diversity. Estimates of the extent of clonality in deep-sea species, despite the importance of clonality in shaping the local dynamics and evolutionary trajectories, have been largely obscured by such limitations. Cold-water coral reefs along European margins are formed mainly by two reef-building species, Lophelia pertusa and Madrepora oculata. Here we present a fine-grained analysis of the genotypic and genetic composition of reefs occurring in the Bay of Biscay, based on an innovative deep-sea sampling protocol. This strategy was designed to be standardized, random, and allowed the georeferencing of all sampled colonies. Clonal lineages discriminated through their Multi-Locus Genotypes (MLG) at 6-7 microsatellite markers could thus be mapped to assess the level of clonality and the spatial spread of clonal lineages. High values of clonal richness were observed for both species across all sites suggesting a limited occurrence of clonality, which likely originated through fragmentation. Additionally, spatial autocorrelation analysis underlined the possible occurrence of fine-grained genetic structure in several populations of both L. pertusa and M. oculata. The two cold-water coral species examined had contrasting patterns of connectivity among canyons, with among-canyon genetic structuring detected in M. oculata, whereas L. pertusa was panmictic at the canyon scale. This study exemplifies that a standardized, random and georeferenced sampling strategy, while challenging, can be applied in the deep sea, and associated benefits outlined here include improved estimates of fine grained patterns of clonality and dispersal that are comparable across sites and among species.  
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  ISSN 0967-0645 ISBN Médium  
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  Numéro d'Appel MARBEC @ alain.herve @ collection 2257  
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Auteur (up) Boavida, J.; Becheler, R.; Choquet, M.; Frank, N.; Taviani, M.; Bourillet, J.-F.; Meistertzheim, A.-L.; Grehan, A.; Savini, A.; Arnaud-Haond, S. doi  openurl
  Titre Out of the Mediterranean? Post-glacial colonization pathways varied among cold-water coral species Type Article scientifique
  Année 2019 Publication Revue Abrégée J. Biogeogr.  
  Volume 46 Numéro 5 Pages 915-931  
  Mots-Clés biodiversity; cold-water corals; computer-program; deep-sea; deep-sea corals; genetic-structure; glacial marine refugia; glacial refugia; growth; in-situ; Last Glacial Maximum; Lophelia pertusa; lophelia-pertusa; Madrepora oculata; marine phylogeography; north-atlantic ocean; software  
  Résumé Aim: To infer cold-water corals' (CWC) post-glacial phylogeography and assess the role of Mediterranean Sea glacial refugia as origins for the recolonization of the northeastern Atlantic Ocean. Location: Northeastern Atlantic Ocean and Mediterranean Sea. Taxon: Lophelia pertusa, Madrepora oculata. Methods: We sampled CWC using remotely operated vehicles and one sediment core for coral and sediment dating. We characterized spatial genetic patterns (microsatellites and a nuclear gene fragment) using networks, clustering and measures of genetic differentiation. Results: Inferences from microsatellite and sequence data were congruent, and showed a contrast between the two CWC species. Populations of L. pertusa present a dominant pioneer haplotype, local haplotype radiations and a majority of endemic variation in lower latitudes. Madrepora oculata populations are differentiated across the northeastern Atlantic and genetic lineages are poorly admixed even among neighbouring sites. Conclusions: Our study shows contrasting post-glacial colonization pathways for two key habitat-forming species in the deep sea. The CWC L. pertusa has likely undertaken a long-range (post-glacial) recolonization of the northeastern Atlantic directly from refugia located along southern Europe (Mediterranean Sea or Gulf of Cadiz). In contrast, the stronger genetic differentiation of M. oculata populations mirrors the effects of long-term isolation in multiple refugia. We suggest that the distinct and genetically divergent, refugial populations initiated the post-glacial recolonization of the northeastern Atlantic margins, leading to a secondary contact in the northern range and reaching higher latitudes much later, in the late Holocene. This study highlights the need to disentangle the influences of present-day dispersal and evolutionary processes on the distribution of genetic polymorphisms, to unravel the influence of past and future environmental changes on the connectivity of cosmopolitan deep-sea ecosystems associated with CWC.  
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  Langue English Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0305-0270 ISBN Médium  
  Région Expédition Conférence  
  Notes WOS:000471344900007 Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 2602  
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Auteur (up) Meistertzheim, A.-L.; Lartaud, F.; Arnaud-Haond, S.; Kalenitchenko, D.; Bessalam, M.; Le Bris, N.; Galand, P.E. url  doi
openurl 
  Titre Patterns of bacteria-host associations suggest different ecological strategies between two reef building cold-water coral species Type Article scientifique
  Année 2016 Publication Revue Abrégée Deep Sea Research Part I: Oceanographic Research Papers  
  Volume 114 Numéro Pages 12-22  
  Mots-Clés Bacterial communities; Bacterial ecology; Deep-Sea corals; Lophelia pertusa; Madrepora oculata; Mediterranean Sea; Microbe-microbe and microbe-host interactions  
  Résumé Cold-water corals (CWC) are main ecosystem engineers of the deep sea, and their reefs constitute hot-spots of biodiversity. However, their ecology remains poorly understood, particularly, the nature of the holobiont formed by corals with their associated bacterial communities. Here, we analyzed Madrepora oculata and Lophelia pertusa samples, collected from one location in a Mediterranean canyon in two different seasons (autumn and spring), in order to test for species specificity and temporal stability of the host-bacteria associations. The 16S rRNA sequencing revealed host-specific patterns of bacterial communities associated with L. pertusa and M. oculata, both in terms of community composition and diversity. All analyzed M. oculata polyps exhibited temporally and spatially similar bacterial communities dominated by haplotypes homologous to the known cnidarians-associated genus Endozoicomonas. In contrast, the bacterial communities associated with L. pertusa varied among polyps from the same colony, as well as among distinct colonies and between seasons. While the resilient consortium formed by M. oculata and its bacterial community fit the definition of holobiont, the versatility of the L. pertusa microbiome suggests that this association is more influenced by the environmental conditions or nutritional status. Our results thus highlight distinct host/microbes association strategies for these two closely related Scleractinians sharing the same habitat, suggesting distinct sensitivity to environmental change.  
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  Langue Langue du Résumé Titre Original  
  Éditeur de collection Titre de collection Titre de collection Abrégé  
  Volume de collection Numéro de collection Edition  
  ISSN 0967-0637 ISBN Médium  
  Région Expédition Conférence  
  Notes Approuvé pas de  
  Numéro d'Appel MARBEC @ isabelle.vidal-ayouba @ collection 1565  
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