A5010782193- Methane Hydrates and Related Phenomena
- Geology and Paleoclimatology Research
- Hydrocarbon exploration and reservoir analysis
- Atmospheric and Environmental Gas Dynamics
- Isotope Analysis in Ecology
- Microbial Community Ecology and Physiology
- Marine Biology and Ecology Research
- earthquake and tectonic studies
- Ocean Acidification Effects and Responses
- High-pressure geophysics and materials
- Marine Bivalve and Aquaculture Studies
- Marine and coastal ecosystems
- Geological and Geochemical Analysis
- Atmospheric Ozone and Climate
- Geochemistry and Elemental Analysis
- Marine animal studies overview
- Underwater Acoustics Research
- Earthquake Detection and Analysis
- Geological Studies and Exploration
- Underwater Vehicles and Communication Systems
- Bacteriophages and microbial interactions
- Geological formations and processes
- Oceanographic and Atmospheric Processes
- Groundwater and Isotope Geochemistry
- Anaerobic Digestion and Biogas Production
Japan Agency for Marine-Earth Science and Technology
2016-2025
ETH Zurich
2017-2021
Woods Hole Oceanographic Institution
2019
The University of Tokyo
2008-2014
Hokkaido University
2005-2008
Japan Aerospace Exploration Agency
2005
Tohoku University
2005
Abstract Microbes can decompose biodegradable plastics on land, rivers and seashore. However, it is unclear whether deep-sea microbes degrade in the extreme environmental conditions of seafloor. Here, we report microbial decomposition representative (polyhydroxyalkanoates, polyesters, polysaccharide esters) at diverse floor locations ranging depth from 757 to 5552 m. The degradation samples was evaluated terms weight loss, reduction material thickness, surface morphological changes. Poly( l...
Geochemical characteristics of hydrothermal fluids in the Iheya North field, mid-Okinawa Trough, was investigated. Twelve-years observation reveals temporal variation vent fluid chemistry potentially controlled by temporally varying pattern phase-separation and -segregation, while constant Element/Cl ratios among periods chimneys indicate stable chemical composition source prior to undergoing phase-separation. The high K contents estimated are typical arc-backarc systems due reaction with...
Scientific drilling at a submarine mud volcano shows that geofluid migration stimulates methanogenesis in the deep biosphere.
The near-Earth carbonaceous asteroid (162173) Ryugu is expected to contain volatile chemical species that could provide information on the origin of Earth's volatiles. Samples were retrieved by Hayabusa2 spacecraft. We measured noble gas and nitrogen isotopes in samples found they are dominated presolar primordial components, incorporated during Solar System formation. Noble concentrations higher than those Ivuna-type (CI) chondrite meteorites. Several host phases isotopically distinct have...
Abstract Hydrogen‐rich hydrothermal areas, such as those in the Indian Ocean, may have had an influence on early evolution of life Earth and thus attracted interest because they be a proxy for ancient ecosystems. The Kairei Edmond fields Ocean are separated by 160 km, but exhibit distinct fluid chemistry: fluids hydrogen‐rich; hydrogen‐poor. At this region, Central Ridge shows intermediate spreading rate, 48 mm year −1 full where hydrothemal occur. field vent show persistently high...
A newly discovered hydrothermal field called the Mariner on Valu Fa Ridge in southern Lau Basin was explored and characterized with geochemical microbiological analyses. The fluid discharging from most vigorous vent (Snow Chimney, maximum discharge temperature 365°C) boiling at seafloor a depth of 1908 m, two distinct end‐member fluids were identified. chemistry typical Cl‐enriched Cl‐depleted analyzed, as mineralogy host chimney structures. variability potentially controlled by subseafloor...
Indian Ocean hydrothermal vents are believed to represent a novel biogeographic province, and host many genera families of animals, potentially indigenous systems. In particular, since its discovery in 2001, much attention has been paid so-called 'scaly-foot' gastropod because unique iron-sulfide-coated dermal sclerites the chemosynthetic symbioses various tissues. Despite increasing interest faunal assemblages at vents, only two vent fields have investigated Ocean. Here we report newly...
[1] Molecular hydrogen, H2, is the key component to link inorganic lithosphere with subsurface biosphere. Geochemical and microbiological characterizations of natural hydrothermal fields strongly suggested that H2 an important energy source in microbial ecosystems because its metabolic versatility. One possible sources has been considered as earthquakes: mechanoradical reactions on fault surfaces generate during earthquake faulting. However it unclear whether faulting can abundant sustain...
Two active hydrothermal fields, Jade and Hakurei fields have been discovered within the Izena Hole, a rectangular 6 km × 3 shape depression located in middle Okinawa Trough back arc basin. In both intense activity is represented by venting of high-temperature fluid (>300°C) occurrence sulfide/sulfate ore deposits. We collected fluids during dive expeditions ROV Hyper Dolphin conducted 2003, 2010 2011, order to analyze elemental gas species. The geochemistry high temperature from very similar...
Polymetallic sulfides deposited in seafloor hydrothermal vents have recently attracted attention as potential deep-sea mineral resources for base, rare, and precious metals such Cu, Zn, Pb, In, Ga, Ge, Au, Ag. For future exploitation of this type resources, development effective methods exploring activity is a key to provide the most promising list fields. However, conventional exploration are likely laborious time-consuming, more efficient be further developed. In last decade, water column...
Abstract Chemosynthetic symbiosis is one of the successful systems for adapting to a wide range habitats including extreme environments, and metabolic capabilities symbionts enable host organisms expand their habitat ranges. However, our understanding adaptive strategies that symbiotic still fragmentary. Here, we report single-ribotype endosymbiont population in an individual vent mussel, Bathymodiolus septemdierum has heterogeneous genomes with regard composition key gene clusters hydrogen...
The Japan Trench is located under the eutrophic Northwestern Pacific while Mariana that harbors unique hadal planktonic biosphere oligotrophic Pacific. Water samples from sea surface to just above seafloor at a total of 11 stations including trench axis station, were investigated several months after Tohoku Earthquake in March 2011. High turbidity zones deep waters observed most sampling stations. small subunit (SSU) rRNA gene community structures (water depths below 6000 m) station distinct...
Hydrogen and carbon isotope systematics of H2O–H2–CO2–CH4 in hydrogenotrophic methanogenesis their relation to H2 availability were investigated. Two H2-syntrophic cocultures fermentatively hydrogenogenic bacteria methanogens under conditions <102 Pa-H2 two pure cultures ~105 tested. Carbon fractionation between CH4 CO2 during was correlated with pH2, as indicated previous studies. The hydrogen ratio produced rapid growth the thermophilic methanogen Methanothermococcus okinawensis high pH2...
The impacts of the M9.0 Tohoku Earthquake on deep-sea environment were investigated 36 and 98 days after event. light transmission anomaly in water became atypically greater (∼35%) more extensive (thickness ∼1500 m) near trench axis owing to turbulent diffusion fresh seafloor sediment, coordinated with potential displacement. In addition chemical influx associated sediment diffusion, an (13)C-enriched methane from deep sub-seafloor reservoirs was estimated. This isotopically unusual possibly...
Deep-sea chemistry: The electrochemical analysis of hydrothermal fluids and the ambient seawater with fuel cells installed in deep-sea vents provided evidence for possibility generating electricity deep sea. illumination light-emitting diodes dark environment also confirmed this prospect.
The Integrated Ocean Drilling Program (IODP) Expedition 331 investigated the Iheya North hydrothermal field in Okinawa Trough. Several post‐drilling underwater vehicle investigations were conducted over 2 years to identify changes fluid discharge pattern, mineral deposition, and chemistry. Drilling‐induced high‐temperature vents identified at deep holes not only near naturally occurring NBC vent (Site C0016) but also seafloor ∼450 m distal C0014), where no was observed prior drilling. A...
Since the initial discovery of hydrothermal vents in 1977, these ‘extreme’ chemosynthetic systems have been a focus interdisciplinary research. The Okinawa Trough (OT), located semi-enclosed East China Sea between Eurasian continent and Ryukyu arc, hosts more than 20 known vent sites but all within relatively narrow depth range (600–1880 m). Depth is significant factor determining fluid temperature chemistry, as well biological composition. However, due to sites, actual influence here has...
Abstract Seafloor massive sulphide deposits are potential resources for base and precious metals (Cu-Pb-Zn ± Ag Au), but difficulties in estimating precise reserves assessing environmental impacts hinder exploration commercial mining. Here, we report petrological geochemical properties of chimneys less than 2 years old that formed where scientific boreholes vented hydrothermal fluids the Iheya-North field, Okinawa Trough, East China Sea. One these infant chimneys, dominated by Cu-Pb-Zn-rich...
Seafloor massive sulfide deposits have attracted much interest as mineral resources. Therefore, the potential environmental impacts of full-scale mining should be considered. In this study, we focused on metal and metalloid contamination that could triggered by accidental leakage dispersion hydrothermal ore particulates from vessels into surface seawater. We determined leaching metals metalloids four ores collected Okinawa Trough aerobic seawater then evaluated toxic effects leachates a...
Abstract Deep‐sea hydrothermal vents host exceptional ecosystems with lush animal communities primarily relying on organic matter (OM) produced by chemoautotrophic microbes. Though energy sources and food webs at have been extensively studied, the exact carbon of chemosynthetic primary production, such as methane (CH 4 ) dioxide (CO 2 in vent fluid or bottom water, not elucidated quantitatively across spatial scales. Here, we investigate nitrogen 12 species Iheya North field, Okinawa Trough...
We analyzed the distribution of turbidity in seawater near epicenter 2011 Tohoku earthquake ( M w 9.0) as well mineral composition and grain size suspended particles shallow sediments cores from same area. One month after an area where large changes bathymetry accompanied earthquake, we observed a strong anomaly above seafloor (maximum 5 mg/L) that greatly exceeded measured several years before (average 0.59 mg/L). The were composed material similar to surface sediment cores, inferred they...
There has been an increasing interest in seafloor exploitation such as mineral mining deep-sea hydrothermal fields, but the environmental impact of anthropogenic disturbance to is poorly known. In this study, effect by scientific drilling operations (IODP Expedition 331) on seabed landscape and megafaunal habitation was surveyed for over 3 years using remotely operated vehicle video observation a field, Iheya North Okinawa Trough. We focused observations from particular site (Site C0014)...