A5018715636- Marine and coastal ecosystems
- Atmospheric chemistry and aerosols
- Arctic and Antarctic ice dynamics
- Methane Hydrates and Related Phenomena
- Atmospheric Ozone and Climate
- Isotope Analysis in Ecology
- Oceanographic and Atmospheric Processes
- Marine Biology and Ecology Research
- Atmospheric and Environmental Gas Dynamics
- Microbial Community Ecology and Physiology
- Atmospheric aerosols and clouds
- Geology and Paleoclimatology Research
- Air Quality Monitoring and Forecasting
- Advanced Chemical Sensor Technologies
- Ocean Acidification Effects and Responses
- Air Quality and Health Impacts
- Marine and environmental studies
- Environmental DNA in Biodiversity Studies
- Marine and coastal plant biology
- Groundwater and Isotope Geochemistry
- Cryospheric studies and observations
- Radioactive contamination and transfer
- Water Quality Monitoring and Analysis
- Food Industry and Aquatic Biology
- Marine and fisheries research
Hokkaido University
2016-2025
Arctic Research Centre
2020-2025
The University of Tokyo
2002-2022
Sphere Institute
2022
Hokkaido Research Organization
2022
National Institute for Environmental Studies
2008-2011
Nitobe Memorial Nakano General Hospital
2003
Acid gas reactions during the passage from source regions to western North Pacific modify chemical characteristics of Asian mineral dust particles as they pass through heavily industrial regions. We conducted aerosol samplings investigate interaction with acid gases in region high‐dust season. The concentration peaks NO 3 − and were coarse mode range ( D > 1.25 μm) all samples, while non‐sea‐salt‐(nss)‐SO 4 2− had an apparent peak only event that experienced rain. Nitrate was dominant...
Asian mineral dust was sampled at Hokkaido, northern Japan, in spring 2004 and 2006. Iron solubility of the bulk aerosol, size‐segregated aerosol (0.45 < D 11 μ m), snow containing a lot dust, simulated standard (CJ‐2) were measured by an iron dissolution experiment using newly developed continuous leaching method. The samples 1.2–2.2%. Within 1.1 m size range, (0.52–8.2%) higher smaller fractions samples. We considered that preferential removal larger particles from air resulted low...
Abstract Isoprene (C 5 H 8 ) and three volatile organic iodine compounds (VOIs: CH 3 I, C 2 ClI) in surface seawater were measured the western Arctic, Northwest Pacific, Indian, Southern Oceans during period 2008–2012. These are believed to play an important role marine atmospheric chemistry after their emission. The measurements performed with high time‐resolution (1–6 h intervals) using online equilibrator gas chromatography mass spectrometer. was most abundant high‐productivity...
The location and magnitude of oceanic iron sources remain uncertain owing to a scarcity data, particularly in the Arctic Ocean. formation cold, dense water subsurface layer western Ocean is key process lateral transport iron, macronutrients, other chemical constituents. Here, we present humic-like fluorescent dissolved organic matter, nutrient concentration data waters above continental slope shelf along two transects across shelf-basin interface We detected high concentrations bottom plume...
We developed an equilibrator inlet-proton transfer reaction-mass spectrometry (EI-PTR-MS) method for fast detection of dimethyl sulfide (DMS) dissolved in seawater. Dissolved DMS extracted by bubbling pure nitrogen through the sample was continuously directed to PTR-MS instrument. The equilibration between seawater and carrier gas, response time system, were evaluated laboratory. reached equilibrium with overall 1 min. limit (50 pmol L(-1) at 5 s integration) sufficient concentrations open...
The spatial distribution of dissolved organic carbon (DOC) concentrations and the optical properties matter (DOM) determined by ultraviolet-visible absorbance fluorescence spectroscopy were measured in surface waters southern Chukchi Sea, western Arctic Ocean, during early summer 2013. Neither DOC concentration nor parameters DOM correlated with salinity. Principal component analysis using clearly separated sources. A significant linear relationship was evident between principal score for...
[1] Source contributions of volatile organic compounds (VOCs) were comprehensively evaluated using an observational data set, two receptor models, and emission inventory. Hourly concentrations C2–C8 nonmethane hydrocarbons (NMHCs) measured at Saitama, which is near the northern edge Tokyo, throughout 2007. Estimates background NMHC Saitama site corresponded well with median a remote island in Japan winter spring. ΔNMHCs (differences between ambient concentrations) calculated by chemical mass...
[1] Four iodocarbons, chloroiodomethane (CH2ClI), diiodomethane (CH2I2), methyl iodide (CH3I), and ethyl (C2H5I), were measured with an automated preconcentration gas chromatography–mass spectrometry system at two remote marine sites, Hateruma Island (24.05°N, 123.8°E) in the East China Sea Cape Ochiishi (43.15°N, 145.5°E) on eastern coast of Hokkaido, for 17 months, giving first full-year high-frequency data sets all these compounds. CH2ClI CH2I2, which are highly photolyzed, showed...
Abstract The lateral transport of nutrient‐rich water masses from coastal areas to offshore is an important factor controlling the primary production phytoplankton in regions. If low‐salinity waters have high nutrient levels, can be traced via salinity observations. However, if level nutrients are not coupled with low salinity, for example, input sediments, cannot In this study, visible fluorescent organic matter (FOM vis ) was monitored by situ sensor as a tracer sediment‐affected areas....
We investigated the chemical characteristics of sea fog and its generation mechanism over northwestern North Pacific from 28 June to 10 July 2001. Continuous aerosol number measurements revealed that scavenged coarse particles (d > 0.50 μm) more efficiently than fine < μm). Although there was no relationship between Na + concentration age, anthropogenic ions concentrations (NO 3 − , nss‐SO 4 2− NH ) decreased with an increase in age. Compared NO selectively removed by fog. Coarse...
Abstract Pacific water is an important nutrient source for sustaining biological production in the Chukchi Sea, western Arctic Ocean, which one of productive regions world. Therefore, to understand impacts future environmental changes on sea, it crucial origins, modification processes, and spatiotemporal variations masses from Bering Sea with concentrations. To improve mass analysis shelf Seas, we observed levels humic‐like fluorescent organic matter (FOM H ) by using situ fluorometer...
The partial pressures of methyl halides (CH 3 X; X = Cl, Br, or I) and CHClF 2 (HCFC‐22), which are all volatile organic compounds (VOCs), were measured in the air marine boundary layer ( p VOC ) surface seawater water during a cruise from subarctic to subtropical regions northwest Pacific summer 2008. In northern transition (TW N with high biological activity, levels three CH Xs frequently observed, probably owing their enhanced production by phytoplankton. Supersaturation Br was only...
The sea-to-air flux of C2H5I (iodoethane) in the Indian Ocean and Southern was estimated from Henry's law constant (KH) measured partial pressures surface seawater air. values KH, defined as ratio molar concentration (mol l–1) to pressure (atm), for ten volatile organic compounds (VOCs) (CFCl3 (CFC-11), C5H8 (isoprene), C2H2F4 (HFC-134a), CHF2Cl (HCFC-22), CH3I, CH2Br2, C2H5I, CH2Cl2, CH2ClI, CHBr3) were with an equilibrator a purge-and-trap system combination gas chromatography-mass...
Saroma-ko Lagoon, located on the Okhotsk Sea coast of Hokkaido, is seasonally covered by flat, homogeneous, easily accessible and safe sea ice. As such, it proves a very useful experimental site for study ice processes, inter-comparison methods, testing equipment, training researchers new to Polar regions. In this contribution, we describe physical, chemical, ecosystem survey at conducted over February 23-28, 2019 under auspices SLOPE2019 (Saroma-ko Lagoon Observations Physico-chemistry...