A5065439474- Methane Hydrates and Related Phenomena
- Microbial Community Ecology and Physiology
- Hydrocarbon exploration and reservoir analysis
- Geology and Paleoclimatology Research
- Genomics and Phylogenetic Studies
- Atmospheric and Environmental Gas Dynamics
- Geological and Geophysical Studies
- Seismic Imaging and Inversion Techniques
- Offshore Engineering and Technologies
- Reservoir Engineering and Simulation Methods
- Marine Biology and Ecology Research
- earthquake and tectonic studies
- Geological Studies and Exploration
- Drilling and Well Engineering
- Environmental DNA in Biodiversity Studies
- Geochemistry and Elemental Analysis
- Paleontology and Stratigraphy of Fossils
- CO2 Sequestration and Geologic Interactions
- Geological formations and processes
- Protist diversity and phylogeny
- Planetary Science and Exploration
- Marine and coastal ecosystems
- Ocean Acidification Effects and Responses
- Coal Properties and Utilization
- Isotope Analysis in Ecology
Japan Agency for Marine-Earth Science and Technology
2015-2024
Tohoku University
2022-2024
Waseda University
2024
Shanghai Jiao Tong University
2023
University of Toronto
2020
Oregon State University
2019
Instituto Andaluz de Ciencias de la Tierra
2019
Consejo Superior de Investigaciones Científicas
2019
Universidad de Granada
2019
Texas A&M University
2019
Diverse microbial communities and numerous energy-yielding activities occur in deeply buried sediments of the eastern Pacific Ocean. Distributions metabolic often deviate from standard model. Rates activities, cell concentrations, populations cultured bacteria vary consistently one subseafloor environment to another. Net rates major principally rely on electron acceptors donors photosynthetic surface world. At open-ocean sites, nitrate oxygen are supplied deepest sedimentary through...
The deep subseafloor biosphere is among the least-understood habitats on Earth, even though huge microbial biomass therein plays an important role for potential long-term controls global biogeochemical cycles. We report here vertical and geographical distribution of microbes their phylogenetic diversities in deeply buried marine sediments Pacific Ocean Margins. During Drilling Program Legs 201 204, we obtained sediment cores from Peru Cascadia Margins that varied with respect to presence...
Microbial communities from a subseafloor sediment core the southwestern Sea of Okhotsk were evaluated by performing both cultivation-dependent and cultivation-independent (molecular) analyses. The core, which extended 58.1 m below seafloor, was composed pelagic clays with several volcanic ash layers containing fine pumice grains. Direct cell counting quantitative PCR analysis archaeal bacterial 16S rRNA gene fragments indicated that populations in approximately 2 to 10 times larger than...
Microbial life inhabits deeply buried marine sediments, but the extent of this vast ecosystem remains poorly constrained. Here we provide evidence for existence microbial communities in ~40° to 60°C sediment associated with lignite coal beds at ~1.5 2.5 km below seafloor Pacific Ocean off Japan. methanogenesis was indicated by isotopic compositions methane and carbon dioxide, biomarkers, cultivation data, gas compositions. Concentrations indigenous cells 1.5 ranged from <10 ~10(4) cm(-3)....
A novel mesophilic sulfur- and thiosulfate-oxidizing bacterium, strain 42BKTT, was isolated from the gas-bubbling sediment at Iheya North hydrothermal system in mid-Okinawa Trough, Japan. The isolate a Gram-negative, non-motile coccoid to oval-shaped bacterium. Growth observed 10-40 degrees C (optimum 28-30 C) pH range 5.0-9.0 6.5-7.0). Strain 42BKTT grew chemolithoautotrophically with elemental sulfur or thiosulfate as sole electron donor oxygen 5 % gas phase) nitrate an acceptor. G +...
Significance Marine sediment covers 70% of Earth’s surface and harbors as much biomass seawater. However, the global taxonomic diversity marine sedimentary communities, spatial distribution that remain unclear. We investigated microbial composition from 40 globally distributed sampling locations, spanning depths 0.1 to 678 m. Statistical analysis reveals oxygen presence or absence organic carbon concentration are key environmental factors for defining communities. Global richness predicted...
Sediment-covered basalt on the flanks of mid-ocean ridges constitutes most Earth's oceanic crust, but composition and metabolic function its microbial ecosystem are largely unknown. By drilling into 3.5-million-year-old subseafloor basalt, we demonstrated presence methane- sulfur-cycling microbes eastern flank Juan de Fuca Ridge. Depth horizons with functional genes indicative methane-cycling sulfate-reducing microorganisms enriched in solid-phase sulfur total organic carbon, host δ(13)C-...
Archaeal community structures in microhabitats a deep-sea hydrothermal vent chimney structure were evaluated through the combined use of culture-independent molecular analyses and enrichment culture methods. A black smoker was obtained from PACMANUS site Manus Basin near Papua New Guinea, subsamples vertical horizontal sections. The elemental composition analyzed different by scanning electron microscopy energy-dispersive X-ray spectroscopy, indicating that zinc sulfur major components while...
A novel mesophilic, sulfur- and thiosulfate-oxidizing bacterium, strain OK10(T), was isolated from deep-sea sediments at the Hatoma Knoll in Mid-Okinawa Trough hydrothermal field. Cells of OK10(T) were short rods, each being motile by means a single polar flagellum. The isolate grew 10-40 degrees C (optimum 25 C) pH 4.5-9.0 6.5). It chemolithoautotrophically with elemental sulfur, sulfide thiosulfate as sole electron donors oxygen acceptor. Molecular hydrogen did not support growth. G+C...
Summary Epsilon‐ Proteobacteria is increasingly recognized as an ecologically significant group of bacteria, particularly in deep‐sea hydrothermal environments. In this study, we studied the spatial distribution, diversity and physiological characteristics epsilon‐ various microbial habitats vicinity a vent occurring Iheya North field Mid‐Okinawa Trough, by using culture‐dependent ‐independent approaches. The were inside outside plume, annelid polychaete tubes. addition, deployed...
A novel mesophilic bacterium, strain GO25(T), was isolated from a nest of hydrothermal vent polychaetes, Paralvinella sp., at the Iheya North field in Mid-Okinawa Trough. Cells were motile short rods with single polar flagellum. Growth observed between 4 and 35 degrees C (optimum 30 C; 13-16 h doubling time) pH 5.4 8.6 6.1). The isolate facultatively anaerobic chemolithoautotroph capable growth using molecular hydrogen, elemental sulfur or thiosulfate as sole energy source, carbon dioxide...
Integrated Ocean Drilling Program (IODP) Expedition 316 Sites C0006 and C0007 examined the deformation front of Nankai accretionary prism offshore Kii Peninsula, Japan. In drilling area, frontal thrust shows unusual behavior as compared to other regions Trough. results, integrated with observations from seismic reflection profiles, suggest that has been active since ∼0.78–0.436 Ma accommodated ∼13 34% estimated plate convergence during time. The remainder likely distributed among...
Remarkable numbers of microbial cells have been observed in global shallow to deep subseafloor sediments. Accumulating evidence indicates that and ancient sediments harbor living life, where the flux nutrients energy are extremely low. However, their physiology requirements remain largely unknown. We used stable isotope tracer incubation nanometer-scale secondary ion MS investigate dynamics carbon nitrogen assimilation activities individual from 219-m-deep lower Pleistocene (460,000 y old)...
ABSTRACT The carbon and energy metabolisms of a variety cultured chemolithoautotrophic Epsilonproteobacteria from deep-sea hydrothermal environments were characterized by both enzymatic genetic analyses. All the tested had all three key reductive tricarboxylic acid (rTCA) cycle activities—ATP-dependent citrate lyase, pyruvate:ferredoxin oxidoreductase, 2-oxoglutarate:ferredoxin oxidoreductase—while they no ribulose 1,5-bisphosphate carboxylase (RubisCO) activity, enzyme in Calvin-Benson...
Phase-separation and -segregation (boiling/distillation of subseafloor hydrothermal fluids) represent the primary mechanisms causing intra-field variations in vent fluid compositions. To determine whether this geochemical process affects formation microbial communities, we examined communities at three different sites located within a few tens meters one another. In addition to chimney structures, colonization devices capturing entrained by fluids were studied, using culture-dependent...
Increasing levels of CO2 in the atmosphere are expected to cause climatic change with negative effects on earth's ecosystems and human society. Consequently, a variety disposal options discussed, including injection into deep ocean. Because dissolution seawater will decrease ambient pH considerably, consequences for deep-water have been predicted. Hence, associated natural reservoirs sea, dynamics gaseous, liquid, solid such environments, great interest science We report here biogeochemical...
Development of an improved technique for separating microbial cells from marine sediments and standardization a high-throughput discriminative cell enumeration method were conducted. We separated various types sediment then recovered the using multilayer density gradients sodium polytungstate and/or Nycodenz, resulting in notably higher percent recovery than previous methods. The efficiency extraction generally depends on depth; new we developed, more 80% total shallow samples (down to 100...
Recovering high quality genomic DNA from environmental samples is a crucial primary step to understand the genetic, metabolic, and evolutionary characteristics of microbial communities through molecular ecological approaches. However, it often challenging because difficulty effective cell lysis without fragmenting DNA. This work aims improve previous SDS-based extraction methods for high-biomass seafloor samples, such as pelagic sediments metal sulfide chimney, obtain weight applicable...
Significance Microbial cells are widespread in diverse deep subseafloor environments; however, the viability, growth, and ecophysiology of these low-abundance organisms poorly understood. Using single-cell–targeted stable isotope probing incubations combined with nanometer-scale secondary ion mass spectrometry, we measured metabolic activity generation times thermally adapted microorganisms within Miocene-aged coal shale bed samples collected from 2 km below seafloor during Integrated Ocean...