A5050044217- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Isotope Analysis in Ecology
- Atmospheric chemistry and aerosols
- Groundwater and Isotope Geochemistry
- Marine and coastal ecosystems
- Wastewater Treatment and Nitrogen Removal
- Radioactive contamination and transfer
- Soil and Water Nutrient Dynamics
- Soil Carbon and Nitrogen Dynamics
- Methane Hydrates and Related Phenomena
- Microbial Community Ecology and Physiology
- Radioactive element chemistry and processing
- Spectroscopy and Laser Applications
- Radioactivity and Radon Measurements
- Composting and Vermicomposting Techniques
- Marine Biology and Ecology Research
- Spacecraft and Cryogenic Technologies
- Microbial Fuel Cells and Bioremediation
- Nuclear and radioactivity studies
- Odor and Emission Control Technologies
- Advanced Chemical Sensor Technologies
- Ammonia Synthesis and Nitrogen Reduction
- Arctic and Antarctic ice dynamics
- Cryospheric studies and observations
Meijo University
2025
Tokyo Institute of Technology
2015-2024
Institute of Science Tokyo
2024
Institute of Materials Science
2024
Tokyo Metropolitan Government
2010
Japan Science and Technology Agency
1999-2009
Bio-oriented Technology Research Advancement Institution
2004
The University of Tokyo
1997-1998
Sumitomo Electric Industries (Japan)
1987
Instituto de Ciencias Agrarias
1956-1965
N2O is a powerful greenhouse gas contributing both to global warming and ozone depletion. While fungi have been identified as putative source of N2O, little known about their production this gas. Here we investigated the N2O-producing ability collection 207 fungal isolates. Seventy strains producing in pure culture were identified. They mostly species from order Hypocreales order-particularly Fusarium oxysporum Trichoderma spp.-and lesser extent orders Eurotiales, Sordariales,...
A new method for the determination of nitrogen isotopomers (intramolecular distribution isotopes) nitrous oxide has been developed. The makes use mass analyses molecular (N2O+) and fragment (NO+) ions N2O on an isotope-ratio spectrometer equipped with a special ion collector system. fragmentation in electron impact source is fairly stable, precision isotope ratio measurements relative to reference gas better than 0.1‰ pure samples introduced from conventional dual-inlet Although it found...
Nitrous oxide (N 2 O) is an important atmospheric greenhouse gas and involved in stratospheric ozone depletion. Analysis of the isotopomer ratios N O (i.e., intramolecular distribution 15 within linear NNO molecule conventional isotope ratios) can elucidate mechanisms production destruction. We analyzed dissolved at a site eastern tropical North Pacific (ETNP) Gulf California (GOC). At these sites, flux to atmosphere extremely high but denitrification activity oxygen minimum zone (OMZ) also...
[1] Isotopomer ratios of N2O (bulk nitrogen and oxygen isotope ratios, δ15Nbulk δ18O, intramolecular 15N site preference, SP) are useful parameters that characterize sources this greenhouse gas also provide insight into production consumption mechanisms. We measured isotopomer emitted from typical Japanese agricultural soils (Fluvisols Andisols) planted with rice, wheat, soybean, vegetables, treated synthetic (urea or ammonium) organic (poultry manure) fertilizers. The results were analyzed...
A molecular analysis of betaproteobacterial ammonia oxidizers and a N(2)O isotopomer were conducted to study the sources emissions during cow manure composting process. Much NO(2)(-)-N NO(3)(-)-N Nitrosomonas europaea-like amoA gene detected at surface, especially top pile, suggesting that these ammonia-oxidizing bacteria (AOB) significantly contribute nitrification which occurs surface layer compost piles. However, (15)N site preference within asymmetric molecule (SP = delta(15)N(alpha) -...
In recent years, research and applications of the N2O site-specific nitrogen isotope composition have advanced, reflecting awareness contribution to anthropogenic greenhouse effect, leading significant progress in instrument development. Further dissemination isotopomer analysis, however, is hampered by a lack internationally agreed gaseous reference materials an uncertain compatibility different laboratories analytical techniques.In first comparison approach, eleven were each provided with...
The isotopic composition of nitrous oxide (N
Although the oceans are a significant source of greenhouse gas nitrous oxide (N 2 O) to atmosphere, magnitude and characteristics this poorly constrained. We present here stable isotope isotopomer (intramolecular distribution 15 N within linear NNO molecule) results for O oxygen isotopic data dissolved from Station ALOHA in subtropical North Pacific gyre near Hawaii. The indicate shallow (∼100–300 m) situ production. Results mass balance models constrain rate production sea‐to‐air flux O. an...
Wastewater treatment processes are believed to be anthropogenic sources of nitrous oxide (N2O) and methane (CH4). However, few studies have examined the mechanisms controlling factors in production these greenhouse gases complex bacterial systems. To elucidate consumption N2O CH4 microbial consortia during wastewater characterize human waste sources, we measured their concentrations isotopomer ratios (elemental isotope site-specific N asymmetric molecules NNO) water gas samples collected by...
Abstract. We describe the first high precision real-time analysis of N2O site-specific isotopic composition at ambient mixing ratios. Our technique is based on mid-infrared quantum cascade laser absorption spectroscopy (QCLAS) combined with an automated preconcentration unit. The QCLAS allows for simultaneous and specific three main stable species, 14N15N16O, 15N14N16O, 14N14N16O, respective relative isotope ratio differences δ15Nα δ 15Nβ. Continuous, stand-alone operation achieved by using...
The relative contribution of fungi, bacteria, and nirS nirK denirifiers to nitrous oxide (N2O) emission with unknown isotopic signature from dairy manure compost was examined by selective inhibition techniques. Chloramphenicol (CHP), cycloheximide (CYH), diethyl dithiocarbamate (DDTC) were used suppress the activity nirK-possessing denitrifiers, respectively. Produced N2O surveyed isotopocule analysis, its 15N site preference (SP) δ18O values compared. Bacteria, nirS, gene abundances...
We measured the intramolecular distribution of 15 N as well conventional nitrogen and oxygen isotope ratios in oceanic nitrous oxide (N 2 O) western North Pacific for first time. In contrast to a nearly homogeneous vertical bulk ratio, wide variation site preference was found, suggesting subsurface deep source mixing production mechanism ocean. The composition O isotopomers quantitatively outlines ocean most significant after terrestrial one.
Abstract. Nitrous oxide (N2O) is a potent greenhouse gas and produced in denitrification nitrification by various microorganisms. Site preference (SP) of 15N N2O, which defined as the difference natural abundance isotopomers 14N15NO 15N14NO relative to 14N14NO, has been reported be useful tool quantitatively distinguish N2O production pathways. To determine representative SP values for each microbial process, we firstly measured enzyme reaction hydroxylamine oxidoreductase (HAO) purified...
The identification of the key nitrous oxide (N2O) production pathways is important to establish a strategy mitigate N2O emission. In this study, we combined real-time gas-monitoring analysis, (15)N stable isotope denitrification functional gene transcriptome analysis and microscale concentration measurements identify main producers in partial nitrification (PN) aerobic granule reactor, which was fed with ammonium acetate. Our results suggest that heterotrophic contributor our PN reactor....