title: In-depth analyses of deep subsurface sediments using 454-pyrosequencing reveals a reservoir of buried fungal communities at record-breaking depths.
abstract: The deep subseafloor, extending from a few centimeters below the sediment surface to several hundred meters into sedimentary deposits, constitutes the deep biosphere and harbors an unexpected microbial diversity. Several studies have described the occurrence, turnover, activity and function of subseafloor prokaryotes; however, subsurface eukaryotic communities still remain largely underexplored. Ribosomal RNA surveys of superficial and near-surface marine sediments have revealed an unexpected diversity of active eukaryotic communities, but knowledge of the diversity of deep subseafloor microeukaryotes is still scarce. Here, we investigated the vertical distribution of DNA and RNA fungal signatures within subseafloor sediments of the Canterbury basin (New Zealand) by 454 pyrotag sequencing of fungal genetic markers. Different shifts between the fungal classes of Tremellomycetes, Sordariomycetes, Eurotiomycetes, Saccharomycetes, Wallemiomycetes, Dothideomycetes, Exobasidiomycetes and Microbotryomycetes were observed. These data provide direct evidence that fungal communities occur at record depths in deep sediments of the Canterbury basin and extend the depth limit of fungal presence and activity, respectively 1740 and 346 mbsf. As most of the fungal sequences retrieved have a cosmopolitan distribution, it indicates that fungi are able to adapt to the deep subseafloor conditions at record-depth and must play important ecological roles in biogeochemical cycles.
authors.affiliation: EA 3882 Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, Université de Brest, Plouzané, France.
authors.forename: Vanessa
authors.initials: V
authors.lastname: Rédou
authors.forename: Maria Cristina
authors.initials: MC
authors.lastname: Ciobanu
authors.forename: Maria G
authors.initials: MG
authors.lastname: Pachiadaki
authors.forename: Virginia
authors.initials: V
authors.lastname: Edgcomb
authors.forename: Karine
authors.initials: K
authors.lastname: Alain
authors.forename: Georges
authors.initials: G
authors.lastname: Barbier
authors.forename: Gaëtan
authors.initials: G
authors.lastname: Burgaud
mesh_terms: D001483:Base Sequence; D005658:Fungi / Q000145:classification* / Q000235:genetics*; D019015:Geologic Sediments / Q000382:microbiology*; D059013:Microbial Consortia / Q000235:genetics*; D009520:New Zealand; D009792:Oceans and Seas; D010802:Phylogeny; D012335:RNA, Ribosomal / Q000235:genetics; D012336:RNA, Ribosomal, 16S / Q000235:genetics; D017422:Sequence Analysis, DNA
chemical_list: D012335:RNA, Ribosomal; D012336:RNA, Ribosomal, 16S
keywords: 454 pyrotag; Canterbury basin; deep subseafloor; fungi; microeukaryotes