title: Comparison of prokaryotic diversity at offshore oceanic locations reveals a different microbiota in the Mediterranean Sea.
abstract: The bacterial and archaeal assemblages at two offshore sites located in polar (Greenland Sea; depth: 50 and 2000 m) and Mediterranean (Ionian Sea; depth 50 and 3000 m) waters were studied by PCR amplification and sequencing of the last 450-500 bp of the 16S rRNA gene. A total of 1621 sequences, together with alignable 16S rRNA gene fragments from the Sargasso Sea metagenome database, were analysed to ascertain variations associated with geographical location and depth. The Ionian 50 m sample appeared to be the most diverse and also had remarkable differences in terms of the prokaryotic groups retrieved; surprisingly, however, many similarities were found at the level of large-scale diversity between the Sargasso database fragments and the Greenland 50 m sample. Most sequences with more than 97% sequence similarity, a value often taken as indicative of species delimitation, were only found at a single location/depth; nevertheless, a few examples of cosmopolitan sequences were found in all samples. Depth was also an important factor and, although both deep-water samples had overall similarities, there were important differences that could be due to the warmer waters at depth of the Mediterranean Sea.
authors.affiliation: División de Microbiología and Evolutionary Genomics Group, Universidad Miguel Hernández, San Juan de Alicante, Spain.
authors.forename: Milagros
authors.initials: M
authors.lastname: Zaballos
authors.forename: Arantxa
authors.initials: A
authors.lastname: López-López
authors.forename: Lise
authors.initials: L
authors.lastname: Ovreas
authors.forename: Sergio Galán
authors.initials: SG
authors.lastname: Bartual
authors.forename: Giuseppe
authors.initials: G
authors.lastname: D'Auria
authors.forename: Jose Carlos
authors.initials: JC
authors.lastname: Alba
authors.forename: Boris
authors.initials: B
authors.lastname: Legault
authors.forename: Ravindra
authors.initials: R
authors.lastname: Pushker
authors.forename: Frida Lise
authors.initials: FL
authors.lastname: Daae
authors.forename: Francisco
authors.initials: F
authors.lastname: Rodríguez-Valera
mesh_terms: D001105:Archaea / Q000145:classification* / Q000235:genetics; D001439:Bacteroides / Q000145:classification / Q000235:genetics; D045848:Fibrobacter / Q000145:classification / Q000235:genetics; D020459:Genes, rRNA / Q000235:genetics; D006116:Greenland; D008522:Mediterranean Sea; D020560:Proteobacteria / Q000145:classification* / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics*; D012623:Seawater / Q000382:microbiology*; D017423:Sequence Analysis, RNA
chemical_list: D012336:RNA, Ribosomal, 16S