A5041326961- Geochemistry and Elemental Analysis
- Radioactive element chemistry and processing
- Paleontology and Stratigraphy of Fossils
- Iron oxide chemistry and applications
- Arsenic contamination and mitigation
- Heavy metals in environment
- Geochemistry and Geologic Mapping
- Radioactive contamination and transfer
- Metal Extraction and Bioleaching
- Catalytic Processes in Materials Science
- Geological and Geochemical Analysis
- Geology and Paleoclimatology Research
- Clay minerals and soil interactions
- Isotope Analysis in Ecology
- Extraction and Separation Processes
- Methane Hydrates and Related Phenomena
- X-ray Spectroscopy and Fluorescence Analysis
- Coal and Its By-products
- Geological and Geophysical Studies
- Marine and environmental studies
- Geomagnetism and Paleomagnetism Studies
- Chemical Synthesis and Characterization
- Selenium in Biological Systems
- Minerals Flotation and Separation Techniques
- Hydrocarbon exploration and reservoir analysis
Japan Agency for Marine-Earth Science and Technology
2016-2025
Tokyo University of Science
2006-2021
Geological Survey of Japan
2020
University of Alberta
2019
Hiroshima University
2008-2015
Planetary Systems (United States)
2008-2015
In-Q-Tel
2010
The migration of REEs in pelagic siliceous sediments were studied, especially (i) accumulation at sea floor to Mn4+ oxides, (ii) release from oxides accompanied with the reductive dissolution during early diagenesis, and (iii) incorporation fixation released phosphates such as apatite below 0.6 meters (mbsf). These processes have been indicated by various geochemical findings: (a) chemical compositions bulk sediment pore water, (b) REE patterns sediment, (c) oxidation states Ce, Mn, Fe host...
The large molybdenum (Mo) isotope fractionation from seawater is caused by the adsorption of Mo on manganese oxides. However, effects oxide mineralogy (crystal structure) and surface coverage have not been investigated. In this study, synthetic todorokite, birnessite, δMnO2 was investigated under a wide range coverages. changed Δ98/95Mo = 2.18 ± 0.05‰ to 2.61 0.06‰ for todorokite; 1.25 2.10 birnessite; 2.19 0.07‰ 2.73 0.08‰ δMnO2. fractionations three oxides were negatively correlated with...
Due to its potential as a paleoredox proxy, there have been many studies on Mo isotopic fractionation during adsorption onto ferromanganese oxides in seawater. However, the mechanisms of both and are still under debate due lack structural information adsorbed species. In this study, XAFS analyses were performed reveal mechanism, based at molecular level, oxides. Molybdenum L3-edge XANES K-edge EXAFS revealed that species surface ferrihydrite was tetrahedrally coordinated outer-sphere...
Abstract Host phase of lanthanum (La) in deep-sea rare-earth elements and yttrium (REY)-rich mud was directly determined by X-ray absorption fine structure (XAFS) micro-focused fluorescence (µ-XRF) analyses. Excitation K edge La high-energy allowed us to avoid severe interferences coexisting such as vanadium titanium XAFS XRF. It revealed for the first time that is accumulated apatite this type sediments.
The abundance, diversity and composition of bacterial archaeal communities in a freshwater iron-rich microbial mat were investigated using culture-dependent culture-independent methods. sampling site is mixing zone where ferrous-iron-rich fluids encounter oxygen-rich environments. Quantitative PCR analysis shows that Bacteria dominated the community (>99% total cell numbers). Phylotypes related to iron-oxidizers Gallionellaceae, methano/methylotrophs Methylophilaceae Methylococcaceae,...
Clays are one of the most abundant minerals on Earth's surface, and they play a significant role in global trace element cycling because their ability to adsorb incorporate range metal cations. However, what extent clay surface reactivities affected by changes pH surrounding environment remains poorly understood. To address this uncertainty, we investigated three common (kaolinite, illite, montmorillonite) compared properties binding capacity prior after acidic treatment (pH ranges from 0...
Abstract Given the high surface reactivity of clay minerals, it is assumed that flocculation will lead to metal accumulation in marginal marine settings. However, degree sorption clays impacted by solution pH and ionic strength, remains unknown whether riverine indeed serve as a sink once they encounter seawater where strength markedly increase. Here, we conducted cadmium (Cd) adsorption experiments three types common minerals – kaolinite, illite montmorillonite. We found 20–30% Cd from...
We have succeeded in operating a transition-edge sensor (TES) spectrometer and evaluating its performance at the SPring-8 synchrotron x-ray light source. The TES consists of 240 pixel National Institute Standards Technology (NIST) system, 220 pixels are operated simultaneously with an energy resolution 4 eV 6 keV rate ∼1 c/s pixel−1. tolerance for high count rates is evaluated terms live time fraction, leading to empirical compromise ∼2 × 103 (all pixels) 5 keV. By utilizing TES’s wideband...
Simple, efficient, and robust method established in this study will contribute to clarify how tungsten (W) isotopes behave the Earth system relative molybdenum (Mo) isotopes.
The yellow coloration mechanism of Camellia chrysantha flowers has been a mystery because the pigments which produce their deep color could not be found in flower. We sought to solve regarding characteristic accumulation aluminum ions by camellia plants. Deep C. contained at three times concentration pale flowers. Three quercetin derivatives, 3-rutinoside, 3-glucoside, and 7-glucoside, were identified as major flavonoids both There no significant differences flavonoid content or pH, was 5.8....
Redox-sensitive metallic elements, Mn and Fe, are oxidized in deep sea waters form abundant ferromanganese crusts nodules on the world's ocean floors at ultraslow rates of growth. This process oxidation mechanism precipitation yet unknown. In this paper, results first successful, long-term, on-site experiment mineral that ascertains modern, ongoing hydrogenetic deposition oxide materials from normal seawaters water depths 900-4500 m geologically active inactive environments presented. We...
A large mass-dependent isotope fractionation of molybdenum (Mo) during its adsorption on marine ferromanganese oxides, which are mixtures iron (Fe) (oxyhydr)oxide and manganese (Mn) oxide, is most likely caused by a geometrical change from tetrahedral (Td) to distorted octahedral (Oh) based X-ray absorption fine structure (XAFS) spectroscopy. However, the understanding such can be enhanced further. In this study, density functional theory (DFT) calculations were conducted examine models Oh...