A5067776837- Methane Hydrates and Related Phenomena
- Geology and Paleoclimatology Research
- Hydrocarbon exploration and reservoir analysis
- Atmospheric and Environmental Gas Dynamics
- Seismic Imaging and Inversion Techniques
- Reservoir Engineering and Simulation Methods
- Microbial Community Ecology and Physiology
- Isotope Analysis in Ecology
- Geological and Geophysical Studies
- earthquake and tectonic studies
- Paleontology and Stratigraphy of Fossils
- Geochemistry and Elemental Analysis
- Marine and coastal ecosystems
- Marine Biology and Ecology Research
- Groundwater and Isotope Geochemistry
- CO2 Sequestration and Geologic Interactions
- Geological formations and processes
- Geological Studies and Exploration
- Geological and Geochemical Analysis
- Marine and environmental studies
- Clay minerals and soil interactions
- Diatoms and Algae Research
- Coal Properties and Utilization
- Arctic and Antarctic ice dynamics
- Metabolomics and Mass Spectrometry Studies
Japan Agency for Marine-Earth Science and Technology
2015-2025
Kobe University
2021-2025
California Maritime Academy
2023
International Ocean Discovery Program
2017-2020
Kōchi University
2017
Shikoku (Japan)
2017
The University of Tokyo
2014
Hokkaido University
2003-2009
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)....
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...
Deep, hot, and more alive than we thought Marine sediments represent a massive microbial ecosystem, but still do not fully understand what factors shape limit life underneath the seafloor. Analyzing samples from subduction zone off coast of Japan, Heuer et al. found that life, in particular bacterial vegetative cells, decreases as depth temperature increases down to ∼600 meters below seafloor, corresponding temperatures ∼70°C. Below this limit, endospores are common—a remnant, potential...
Scientific drilling at a submarine mud volcano shows that geofluid migration stimulates methanogenesis in the deep biosphere.
We have discovered deep-sea mud that is extremely enriched in rare-earth elements and yttrium (together called REY) the Japanese Exclusive Economic Zone around Minamitorishima Island, western North Pacific Ocean. The maximum total REY concentration reaches approximately 7000 ppm, which much higher than reported for conventional deposits on land other known potential resources ocean. REY-rich characterized by abundant phillipsite biogenic calcium phosphate. In addition, stratigraphic layer...
Submarine mud volcanoes (SMVs) are formed by muddy sediments and breccias extruded to the seafloor from a source in deep subseafloor characterized discharge of methane other hydrocarbon gases deep-sourced fluids into overlying seawater. Although SMVs act as natural pipeline connecting Earth's surface subsurface biospheres, dispersal deep-biosphere microorganisms their ecological roles remain largely unknown. In this study, we investigated microbial communities sediment seawater at two...
We report detailed lithological and chemical characteristics of deep-sea sediments, including rare-earth elements yttrium-rich mud (REY-rich mud), in the Japanese Exclusive Economic Zone (EEZ) around Minamitorishima Island. Three research cruises obtained fourteen sediment cores collected by piston coring. Based on visual descriptions geochemical analysis cores, we confirm presence REY-rich containing more than 400 ppm total REY (∑REY) southern northwestern areas EEZ. The layers are...
<strong class="journal-contentHeaderColor">Abstract.</strong> Integrated Ocean Drilling Program (IODP) Expedition 331 drilled into the Iheya North hydrothermal system in middle Okinawa Trough order to investigate active subseafloor microbial ecosystems and their physical chemical settings. We five sites during using special guide bases at three holes for reentry, casing, capping, including installation of a steel mesh platform with valve controls postcruise sampling fluids. At Site C0016,...
Abstract Serpentinization of ultramafic rocks provides molecular hydrogen (H2) that can support lithotrophic metabolism microorganisms, but also poses extremely challenging conditions, including hyperalkalinity and limited electron acceptor availability. Investigation two serpentinization-active systems reveals conventional H2-/CO2-dependent homoacetogenesis is thermodynamically unfavorable in situ due to picomolar CO2 levels. Through metagenomics thermodynamics, we discover unique taxa...
A well-preserved fossil seep community has been found in a carbonate lens the Santonian to Campanian Omagari Formation, Upper Yezo Group Nakagawa region, Hokkaido, north Japan. The (roughly ellipsoidal plan view with diameter of 10 m × 6 m, and thickness about 5 m) is composed mainly various types high-Mg calcite containing several mol% magnesium little iron or manganese. divided into an upper tube worm-dominated boundstone lower breccia facies. In facies, concentric cements occur...
ABSTRACT The impacts of lithologic structure and geothermal gradient on subseafloor microbial communities were investigated at a marginal site the Iheya North hydrothermal field in Mid-Okinawa Trough. Subsurface marine sediments composed hemipelagic muds volcaniclastic deposits recovered through depth 151 m below seafloor C0017 during Integrated Ocean Drilling Program Expedition 331. Microbial inferred from 16S rRNA gene clone sequencing low-temperature mainly members Chloroflexi deep-sea...
Chemical and isotopic compositions of hydrothermal fluids from Hatoma Knoll in the southern Okinawa Trough were investigated. The derived a single pure fluid source, but they underwent phase separation beneath seafloor prior to venting. Only vapor-like vent at system, most active area is around center crater, based on location maximum temperature lowest Cl– concentrations. Compared with other systems world, pH alkalinity, as well B, NH4+, K, Li, CO2, CH4 concentrations, higher, Fe Al...
Geological CO2 sequestration in unmineable subsurface oil/gas fields and coal formations has been proposed as a means of reducing anthropogenic greenhouse gasses the atmosphere. However, feasibility injecting into depends upon variety geological economic conditions, ecological consequences are largely unpredictable. In this study, we developed new flow-through-type reactor system to examine potential geophysical, geochemical microbiological impacts associated with injection by simulating...
Abstract Recent explorations of scientific ocean drilling have revealed the presence microbial communities persisting in sediments down to ~2.5 km below floor. However, our knowledge these populations deep subseafloor sedimentary biosphere remains limited. Here, we present a cultivation experiment 2-km-deep 20-million-year-old lignite coalbeds using continuous-flow bioreactor operating at 40 °C for 1029 days with particles as major energy source. Chemical monitoring effluent samples via...
Pore waters were taken from core sediments of Sites C0001, C0004, and C0008 on the landward slope Nankai Trough Site C0002 in forearc basin accretionary prism off Kumano during Integrated Ocean Drilling Program Expeditions 315 316. The carbon isotopic ratios CH4 total dioxide (∑CO2) dissolved gases measured. contribution thermogenic was negligible at all sites, while separation between ∑CO2 indicated that formation mainly by microbial hydrogenotrophic methanogenesis. Evaluation fraction...
We used push corers during manned submersible dives to obtain sediment samples of up 30 cm from the subseafloor at Oomine Ridge. The concentrations B in pore water extracted cold seep sites were higher than could be explained by organic matter decomposition, suggesting that seepage fluid site was influenced derived smectite-illite alteration, which occurs between 50°C and 160°C. Although negative δ18OH2O δDH2O values fluids cannot freshwater clay mineral dehydration (CMD), we considered...