title: Global diversity and biogeography of deep-sea pelagic prokaryotes.
abstract: The deep-sea is the largest biome of the biosphere, and contains more than half of the whole ocean's microbes. Uncovering their general patterns of diversity and community structure at a global scale remains a great challenge, as only fragmentary information of deep-sea microbial diversity exists based on regional-scale studies. Here we report the first globally comprehensive survey of the prokaryotic communities inhabiting the bathypelagic ocean using high-throughput sequencing of the 16S rRNA gene. This work identifies the dominant prokaryotes in the pelagic deep ocean and reveals that 50% of the operational taxonomic units (OTUs) belong to previously unknown prokaryotic taxa, most of which are rare and appear in just a few samples. We show that whereas the local richness of communities is comparable to that observed in previous regional studies, the global pool of prokaryotic taxa detected is modest (~3600 OTUs), as a high proportion of OTUs are shared among samples. The water masses appear to act as clear drivers of the geographical distribution of both particle-attached and free-living prokaryotes. In addition, we show that the deep-oceanic basins in which the bathypelagic realm is divided contain different particle-attached (but not free-living) microbial communities. The combination of the aging of the water masses and a lack of complete dispersal are identified as the main drivers for this biogeographical pattern. All together, we identify the potential of the deep ocean as a reservoir of still unknown biological diversity with a higher degree of spatial complexity than hitherto considered.
authors.affiliation: Institut de Cieènces del Mar, CSIC, Barcelona, Catalunya, Spain.
authors.forename: Guillem
authors.identifier: http://orcid.org/0000-0002-9786-1493
authors.initials: G
authors.lastname: Salazar
authors.affiliation: Institut de Cieènces del Mar, CSIC, Barcelona, Catalunya, Spain.
authors.forename: Francisco M
authors.initials: FM
authors.lastname: Cornejo-Castillo
authors.affiliation: Instituto Español de Oceanografía, Centro Oceanográfico de Canarias, Santa Cruz de Tenerife, Spain.
authors.forename: Verónica
authors.initials: V
authors.lastname: Benítez-Barrios
authors.affiliation: Instituto Español de Oceanografía, Centro Oceanográfico de Canarias, Santa Cruz de Tenerife, Spain.
authors.forename: Eugenio
authors.initials: E
authors.lastname: Fraile-Nuez
authors.affiliation: Instituto de Investigacións Mariñas, CSIC, Vigo, Spain.
authors.forename: X Antón
authors.initials: XA
authors.lastname: Álvarez-Salgado
authors.affiliation: Department of Global Change Research, IMEDEA (CSIC-UIB) Instituto Mediterráneo de Estudios Avanzados, Esporles, Spain.|King Abdullah University of Science and Technology (KAUST), Red Sea Research Center (RSRC), Thuwal, Saudi Arabia.
authors.forename: Carlos M
authors.initials: CM
authors.lastname: Duarte
authors.affiliation: Institut de Cieènces del Mar, CSIC, Barcelona, Catalunya, Spain.
authors.forename: Josep M
authors.initials: JM
authors.lastname: Gasol
authors.affiliation: Institut de Cieènces del Mar, CSIC, Barcelona, Catalunya, Spain.
authors.forename: Silvia G
authors.initials: SG
authors.lastname: Acinas
mesh_terms: D001419:Bacteria / Q000145:classification / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D044822:Biodiversity; D009792:Oceans and Seas; D010802:Phylogeny; D012623:Seawater / Q000382:microbiology*; D012965:Sodium Chloride / Q000032:analysis / Q000378:metabolism
chemical_list: D012965:Sodium Chloride