title: Sediment Microbial Diversity of Three Deep-Sea Hydrothermal Vents Southwest of the Azores.
abstract: Menez Gwen, Lucky Strike and Rainbow are the three most visited and well-known deep-sea hydrothermal vent fields in the Azores region, located in the Mid-Atlantic Ridge. Their distinct geological and ecological features allow them to support a diversity of vent communities, which are largely dependent on Bacteria and Archaea capable of anaerobic or microaerophilic metabolism. These communities play important ecological roles through chemoautotrophy, feeding and in establishing symbiotic associations. However, the occurrence and distribution of these microbes remain poorly understood, especially in deep-sea sediments. In this study, we provide for the first time a comparative survey of the sediment-associated microbial communities from these three neighbouring vent fields. Sediment samples collected in the Menez Gwen, Lucky Strike and Rainbow vent fields showed significant differences in trace-metal concentrations and associated microbiomes. The taxonomic profiles of bacterial, archaeal and eukaryotic representatives were assessed by rRNA gene-tag pyrosequencing, identified anaerobic methanogens and microaerobic Epsilonproteobacteria, particularly at the Menez Gwen site, suggesting sediment communities potentially enriched in sub-seafloor microbes rather than from pelagic microbial taxa. Cosmopolitan OTUs were also detected mostly at Lucky Strike and Rainbow sites and affiliated with the bacterial clades JTB255, Sh765B-TzT-29, Rhodospirillaceae and OCS155 marine group and with the archaeal Marine Group I. Some variations in the community composition along the sediment depth were revealed. Elemental contents and hydrothermal influence are suggested as being reflected in the composition of the microbial assemblages in the sediments of the three vent fields. Altogether, these findings represent valuable information for the understanding of the microbial distribution and potential ecological roles in deep-sea hydrothermal fields.
authors.affiliation: Department of Oceanography and Fisheries, University of the Azores, Rua Prof. Dr. Frederico Machado, 4, 9901-862, Horta, Portugal. mt.cerqueira@mare-centre.pt.|MARE-Marine and Environmental Sciences Centre-Azores, Rua Prof. Dr. Frederico Machado, 4, 9901-862, Horta, Portugal. mt.cerqueira@mare-centre.pt.
authors.forename: Teresa
authors.identifier: 0000-0002-3397-574X
authors.initials: T
authors.lastname: Cerqueira
authors.affiliation: Next Generation Sequencing Unit, UCBiotech-CNC, Parque Tecnológico de Cantanhede, Núcleo 04, Lote 8, 3060-197, Cantanhede, Portugal.
authors.forename: Diogo
authors.initials: D
authors.lastname: Pinho
authors.affiliation: Next Generation Sequencing Unit, UCBiotech-CNC, Parque Tecnológico de Cantanhede, Núcleo 04, Lote 8, 3060-197, Cantanhede, Portugal.
authors.forename: Hugo
authors.initials: H
authors.lastname: Froufe
authors.affiliation: Department of Oceanography and Fisheries, University of the Azores, Rua Prof. Dr. Frederico Machado, 4, 9901-862, Horta, Portugal.|MARE-Marine and Environmental Sciences Centre-Azores, Rua Prof. Dr. Frederico Machado, 4, 9901-862, Horta, Portugal.|OKEANOS Centre, Department of Oceanography and Fisheries, Faculty of Sciences and Technology, University of the Azores, Rua Prof. Dr. Frederico Machado, 4, 9901-862, Horta, Portugal.
authors.forename: Ricardo S
authors.initials: RS
authors.lastname: Santos
authors.affiliation: MARE-Marine and Environmental Sciences Centre-Azores, Rua Prof. Dr. Frederico Machado, 4, 9901-862, Horta, Portugal.|OKEANOS Centre, Department of Oceanography and Fisheries, Faculty of Sciences and Technology, University of the Azores, Rua Prof. Dr. Frederico Machado, 4, 9901-862, Horta, Portugal.
authors.forename: Raul
authors.initials: R
authors.lastname: Bettencourt
authors.affiliation: Next Generation Sequencing Unit, UCBiotech-CNC, Parque Tecnológico de Cantanhede, Núcleo 04, Lote 8, 3060-197, Cantanhede, Portugal.
authors.forename: Conceição
authors.initials: C
authors.lastname: Egas
mesh_terms: D001105:Archaea / Q000145:classification*; D001267:Atlantic Ocean; D001394:Azores; D001419:Bacteria / Q000145:classification*; D056890:Eukaryota / Q000145:classification*; D019015:Geologic Sediments / Q000382:microbiology*; D060086:Hydrothermal Vents / Q000382:microbiology*; D010802:Phylogeny; D012336:RNA, Ribosomal, 16S
chemical_list: D012336:RNA, Ribosomal, 16S
keywords: Deep-sea sediments; Hydrothermal vent field; Lucky Strike; Menez Gwen; Microbial diversity; Pyrosequencing; Rainbow