title: Variability of subseafloor viral abundance at the geographically and geologically distinct continental margins.
abstract: We studied the relationship between viral particle and microbial cell abundances in marine subsurface sediments from three geographically distinct locations in the continental margins (offshore of the Shimokita Peninsula of Japan, the Cascadia Margin off Oregon, and the Gulf of Mexico) and found depth variations in viral abundances among these sites. Viruses in sediments obtained offshore of the Shimokita and in the Cascadia Margin generally decreased with increasing depth, whereas those in sediments from the Gulf of Mexico were relatively constant throughout the investigated depths. In addition, the abundance ratios of viruses to microbial cells notably varied among the sites, ranging between 10(-3) and 10(1) . The subseafloor viral abundance offshore of the Shimokita showed a positive relationship with the microbial cell abundance and the sediment porosity. In contrast, no statistically significant relationship was observed in the Cascadia Margin and the Gulf of Mexico sites, presumably due to the long-term preservation of viruses from enzymatic degradation within the low-porosity sediments. Our observations indicate that viral abundance in the marine subsurface sedimentary environment is regulated not only by in situ production but also by the balance of preservation and decay, which is associated with the regional sedimentation processes in the geological settings.
authors.affiliation: Subsurface Geobiology and Advanced Research (SUGAR) Project, Japan Agency for Marine-Earth Science and Technology, Yokosuka, Japan; Department of Earth and Planetary Science, Graduate School of Science, The University of Tokyo, Tokyo, Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Yanagawa
authors.forename: Yuki
authors.initials: Y
authors.lastname: Morono
authors.forename: Yukari
authors.initials: Y
authors.lastname: Yoshida-Takashima
authors.forename: Masamitsu
authors.initials: M
authors.lastname: Eitoku
authors.forename: Michinari
authors.initials: M
authors.lastname: Sunamura
authors.forename: Fumio
authors.initials: F
authors.lastname: Inagaki
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Imachi
authors.forename: Ken
authors.initials: K
authors.lastname: Takai
authors.forename: Takuro
authors.initials: T
authors.lastname: Nunoura
mesh_terms: D017753:Ecosystem; D019015:Geologic Sediments / Q000737:chemistry / Q000821:virology*; D055593:Geological Phenomena; D007564:Japan; D008800:Mexico; D009922:Oregon; D010140:Pacific Ocean; D014780:Viruses / Q000302:isolation & purification*
keywords: deep-sea sedimentary environment; phage; subsurface viruses; viral decay