title: Distribution and Niche Separation of Planktonic Microbial Communities in the Water Columns from the Surface to the Hadal Waters of the Japan Trench under the Eutrophic Ocean.
abstract: The Japan Trench is located under the eutrophic Northwestern Pacific while the Mariana Trench that harbors the unique hadal planktonic biosphere is located under the oligotrophic Pacific. Water samples from the sea surface to just above the seafloor at a total of 11 stations including a trench axis station, were investigated several months after the Tohoku Earthquake in March 2011. High turbidity zones in deep waters were observed at most of the sampling stations. The small subunit (SSU) rRNA gene community structures in the hadal waters (water depths below 6000 m) at the trench axis station were distinct from those in the overlying meso-, bathy and abyssopelagic waters (water depths between 200 and 1000 m, 1000 and 4000 m, and 4000 and 6000 m, respectively), although the SSU rRNA gene sequences suggested that potential heterotrophic bacteria dominated in all of the waters. Potential niche separation of nitrifiers, including ammonia-oxidizing archaea (AOA), was revealed by quantitative PCR analyses. It seems likely that Nitrosopumilus-like AOAs respond to a high flux of electron donors and dominate in several zones of water columns including shallow and very deep waters. This study highlights the effects of suspended organic matter, as induced by seafloor deformation, on microbial communities in deep waters and confirm the occurrence of the distinctive hadal biosphere in global trench environments hypothesized in the previous study.
authors: Marine Functional Biology Group, Research and Development Center for Marine Biosciences, Japan Agency for Marine-Earth Science and Technology Yokosuka, Japan.
authors: Takuro
authors: T
authors: Nunoura
authors: Marine Functional Biology Group, Research and Development Center for Marine Biosciences, Japan Agency for Marine-Earth Science and Technology Yokosuka, Japan.
authors: Miho
authors: M
authors: Hirai
authors: Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science and Technology Yokosuka, Japan.
authors: Yukari
authors: Y
authors: Yoshida-Takashima
authors: Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science and Technology Yokosuka, Japan.
authors: Manabu
authors: M
authors: Nishizawa
authors: Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science and Technology Yokosuka, Japan.
authors: Shinsuke
authors: S
authors: Kawagucci
authors: Marine Functional Biology Group, Research and Development Center for Marine Biosciences, Japan Agency for Marine-Earth Science and Technology Yokosuka, Japan.
authors: Taichi
authors: T
authors: Yokokawa
authors: Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science and Technology Yokosuka, Japan.
authors: Junichi
authors: J
authors: Miyazaki
authors: Marine Functional Biology Group, Research and Development Center for Marine Biosciences, Japan Agency for Marine-Earth Science and Technology Yokosuka, Japan.
authors: Osamu
authors: O
authors: Koide
authors: Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science and Technology Yokosuka, Japan.
authors: Hiroko
authors: H
authors: Makita
authors: Marine Functional Biology Group, Research and Development Center for Marine Biosciences, Japan Agency for Marine-Earth Science and TechnologyYokosuka, Japan; Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science and TechnologyYokosuka, Japan.
authors: Yoshihiro
authors: Y
authors: Takaki
authors: Department of Earth and Planetary Science, The University of Tokyo Tokyo, Japan.
authors: Michinari
authors: M
authors: Sunamura
authors: Department of Subsurface Geobiological Analysis and Research, Japan Agency for Marine-Earth Science and Technology Yokosuka, Japan.
authors: Ken
authors: K
authors: Takai
keywords: deep ocean; hadal; niche separation; nitrification; trench