In-depth analyses of deep subsurface sediments using 454-pyrosequencing reveals a reservoir of buried fungal communities. Canterbury basin

In this study, we investigated the vertical distribution of DNA and RNA fungal signatures within subseafloor sediments of the Canterbury basin, along a depth profile, by 454 pyrotag sequencing of eukaryotic V1-V3 SSU rRNA genes and the fungal ITS1 region. Most operational taxonomic units (OTUs) belonged to Dikarya. 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 at which fungal signatures were detected to 1740 mbsf and the depth limit of fungal activity to 346 mbsf. As most of the fungal sequences retrieved have a cosmopolitan distribution in terrestrial, freshwater and marine environments, 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.