A5020542108- Marine and coastal ecosystems
- Marine Biology and Ecology Research
- Oceanographic and Atmospheric Processes
- Methane Hydrates and Related Phenomena
- Isotope Analysis in Ecology
- Arctic and Antarctic ice dynamics
- Geology and Paleoclimatology Research
- Microbial Community Ecology and Physiology
- Marine and environmental studies
- Geochemistry and Elemental Analysis
- Ocean Acidification Effects and Responses
- Atmospheric and Environmental Gas Dynamics
- Heavy metals in environment
- Aquatic Ecosystems and Phytoplankton Dynamics
- Mercury impact and mitigation studies
- Groundwater and Isotope Geochemistry
- Atmospheric chemistry and aerosols
- Geological Studies and Exploration
- Cryospheric studies and observations
- Water Quality Monitoring and Analysis
- Aquatic and Environmental Studies
- Polar Research and Ecology
- Geochemistry and Geologic Mapping
- Coastal and Marine Dynamics
- Marine Bivalve and Aquaculture Studies
Hokkaido University
2015-2024
B. Verkin Institute for Low Temperature Physics and Engineering of the National Academy of Sciences of Ukraine
2010-2020
NEC (Japan)
2009-2015
Central Research Institute of Electric Power Industry
2001-2014
Saitama University
2009
Waseda University
2006
Hitachi (Japan)
2005
The University of Tokyo
2003
National Institute for Environmental Studies
2003
Japan Fisheries Research and Education Agency
2003
Comparison of eight iron experiments shows that maximum Chl a , the DIC removal, and overall DIC/Fe efficiency all scale inversely with depth wind mixed layer (WML) defining light environment. Moreover, lateral patch dilution, sea surface irradiance, temperature, grazing play additional roles. The Southern Ocean were most influenced by very deep WMLs. In contrast, conditions favorable during SEEDS SERIES as well IronEx‐2. two extreme experiments, EisenEx SEEDS, can be linked via bottle...
We have performed an in situ test of the iron limitation hypothesis subarctic North Pacific Ocean. A single enrichment dissolved caused a large increase phytoplankton standing stock and decreases macronutrients carbon dioxide. The dominant species shifted after addition from pennate diatoms to centric diatom, Chaetoceros debilis, that showed very high growth rate, 2.6 doublings per day. conclude bioavailability regulates magnitude biomass key determine biogeochemical sensitivity supply...
Iron solubilities of Fe(III) hydroxide in coastal and oceanic waters the ultraviolet (UV)‐irradiated seawaters over a pH range 5.7–8.2 at 20°C were determined by simple filtration (0.025 µ m) involving γ ‐activity measurement 59 Fe. At ranges 5.7–7.2 (coastal water) 5.7–7.6 (oceanic water), only Fe(OH) 2 + species is significant. The calculated solubility products, log* K SO , for 4.8–5.0 4.4–4.6, respectively. within 7.8–8.2 are relatively independent aging time. Solubility water was about...
Iron is an essential nutrient and plays important role in the control of phytoplankton growth (Martin et al., 1989). Atmospheric dust has been thought to be most source iron, supporting annual biological production western subarctic Pacific (WSP) (Duce Tindale, 1991; Moore 2002). We argue here for another iron WSP. found extremely high concentrations dissolved particulate Okhotsk Sea Intermediate Water (OSIW) North (NPIW), water ventilation processes this region probably transport through...
The GEOTRACES Intermediate Data Product 2014 (IDP2014) is the first publicly available data product of international programme, and contains measured quality controlled before end 2013. It consists two parts: (1) a compilation digital for more than 200 trace elements isotopes (TEIs) as well classical hydrographic parameters, (2) eGEOTRACES Electronic Atlas providing strongly inter-linked on-line atlas including 300 section plots 90 animated 3D scenes. IDP2014 covers Atlantic, Arctic, Indian...
Abstract The discovery that melting sea ice can fertilize iron (Fe)-depleted polar waters has recently fostered trace metal research efforts in ice. aim of this review is to summarize and synthesize the current understanding Fe biogeochemistry To do so, we compiled available data on particulate, dissolved, total dissolvable (PFe, DFe TDFe, respectively) from sea-ice studies both regions sub-Arctic northern Hemisphere temperate areas. Data analysis focused a circum-Antarctic dataset derived...
Abstract Over the past two decades, with recognition that ocean’s sea-ice cover is neither insensitive to climate change nor a barrier light and matter, research in biogeochemistry has accelerated significantly, bringing together multi-disciplinary community from variety of fields. This disciplinary diversity contributed wide range methodological techniques approaches studies, complicating comparisons results development conceptual numerical models describe important biogeochemical processes...
The mechanism by which nutrients in the deep ocean are uplifted to maintain nutrient-rich surface waters subarctic Pacific has not been properly described. iron (Fe) supply processes that control biological production also still under debate. Here, we report determine chemical properties of intermediate water and uplift Fe main thermocline, eventually maintains productivity. Extremely is pooled (26.8 27.6 σ θ ) western area, especially Bering Sea basin. Increases two four orders upward...
Abstract Black carbon (BC), a byproduct of biomass and fossil fuel combustion, may impact the climate because it can be stored on Earth’s surface for centuries to millennia. Dissolved BC (DBC) occurs ubiquitously in ocean. However, DBC cycle ocean has not been well constrained. Here, we show basin-scale distribution Pacific Ocean find that concentrations deep decrease along with deep-ocean meridional circulation. The concentration is negatively correlated apparent oxygen utilization, proxy...
Multiyear (2003Multiyear ( -2008) ) time series observations along the A line provided information on temporal variability of dissolved iron (diss-Fe) concentration in Oyashio region western subarctic Pacific, and data indicated that there was an annual cycle surface diss-Fe occurring every year.Diss-Fe supplied into water this winter supports spring phytoplankton bloom after development thermocline.The drawn down during period depleted summer some masses.Then increased from autumn to with...
Abstract It is well known that phytoplankton growth broadly limited by iron (Fe) availability in the subarctic Pacific. To investigate which Fe sources control amplitude of seasonal variation biogeochemical parameters Pacific, we examined spatial west‐to‐east distribution dissolved (DFe) across western and central Pacific through Japanese GEOTRACES program. The vertical section profile gyre showed high concentrations from bottom surface mixed layer to as deep approximately 3000 m, suggesting...
Abstract The subarctic Pacific is a high‐nutrient low‐chlorophyll (HNLC) region in which phytoplankton growth broadly limited by iron (Fe) availability. However, even with Fe limitation, the western (WSP) has significant and greater seasonal variability lower trophic levels than eastern Pacific. Therefore, differences supply must explain west‐to‐east decrease growth. flux to euphotic zone WSP occurs at “moderate” value, that it significantly higher its value on side, yet not sufficient...
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...
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...