title: Pyrosequencing analysis of microbial communities reveals dominant cosmopolitan phylotypes in deep-sea sediments of the eastern Mediterranean Sea.
abstract: The deep eastern basin of the Mediterranean Sea is considered to be one of the world's most oligotrophic areas in the world. Here we performed pyrosequenicng analysis of bacterial and archaeal communities in oxic nutrient-poor sediments collected from the eastern Mediterranean at 1025-4393 m depth. Microbial communities were surveyed by targeting the hypervariable V5-V6 regions of the 16S ribosomal RNA gene using bar-coded pyrosequencing. With a total of 13,194 operational taxonomic units (OTUs) or phylotypes at 97% sequence similarities, the phylogenetic affiliation of microbes was assigned to 23 bacterial and 2 archaeal known phyla, 23 candidate divisions at the phylum level and distributed into 186 families. It was further revealed that the microbial consortia inhabiting all sampling sites were highly diverse, but dominated by phylotypes closely related to members of the genus Pseudomonas and Marine Group I archaea. Such pronounced and widespread enrichment probably manifests the cosmopolitan character of these species and raises questions about their metabolic adaptation to the physical stressors and low nutrient availability of the deep eastern Mediterranean Sea.
authors.affiliation: Hellenic Centre for Marine Research (IMBBC-HCMR), Institute of Marine Biology, Biotechnology and Aquaculture, Gournes Pediados, 71500 Heraklion Crete, Greece. Electronic address: polymen@hcmr.gr.
authors.forename: Paraskevi N
authors.initials: PN
authors.lastname: Polymenakou
authors.affiliation: Hellenic Centre for Marine Research (IMBBC-HCMR), Institute of Marine Biology, Biotechnology and Aquaculture, Gournes Pediados, 71500 Heraklion Crete, Greece.
authors.forename: Christos A
authors.initials: CA
authors.lastname: Christakis
authors.affiliation: Hellenic Centre for Marine Research (IMBBC-HCMR), Institute of Marine Biology, Biotechnology and Aquaculture, Gournes Pediados, 71500 Heraklion Crete, Greece.
authors.forename: Manolis
authors.initials: M
authors.lastname: Mandalakis
authors.affiliation: Hellenic Centre for Marine Research (IMBBC-HCMR), Institute of Marine Biology, Biotechnology and Aquaculture, Gournes Pediados, 71500 Heraklion Crete, Greece.
authors.forename: Anastasis
authors.initials: A
authors.lastname: Oulas
mesh_terms: D001105:Archaea / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D001419:Bacteria / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification* / Q000378:metabolism; D044822:Biodiversity; D019641:DNA, Archaeal / Q000235:genetics; D004269:DNA, Bacterial / Q000235:genetics; D019015:Geologic Sediments / Q000382:microbiology*; D059014:High-Throughput Nucleotide Sequencing; D008522:Mediterranean Sea; D059013:Microbial Consortia; D010802:Phylogeny; D011549:Pseudomonas / Q000145:classification / Q000235:genetics / Q000302:isolation & purification; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D012623:Seawater / Q000382:microbiology; D017422:Sequence Analysis, DNA
chemical_list: D019641:DNA, Archaeal; D004269:DNA, Bacterial; D012336:RNA, Ribosomal, 16S
keywords: Cosmopolitan species; Deep-sea sediments; Eastern Mediterranean Sea; Microbial diversity; Pseudomonas; Pyrosequencing