A5028809453- Marine and coastal ecosystems
- Marine Biology and Ecology Research
- Microbial Community Ecology and Physiology
- Arctic and Antarctic ice dynamics
- Isotope Analysis in Ecology
- Methane Hydrates and Related Phenomena
- Cryospheric studies and observations
- Atmospheric and Environmental Gas Dynamics
- Climate change and permafrost
- Atmospheric chemistry and aerosols
- Ocean Acidification Effects and Responses
- Aquatic and Environmental Studies
- Water Quality Monitoring and Analysis
- Wastewater Treatment and Nitrogen Removal
- Polar Research and Ecology
- Food Industry and Aquatic Biology
- Marine and coastal plant biology
- Marine Bivalve and Aquaculture Studies
- Marine and environmental studies
- Biodiesel Production and Applications
- Algal biology and biofuel production
- Radioactive contamination and transfer
- Physiological and biochemical adaptations
- Environmental DNA in Biodiversity Studies
Tokai University
2020-2024
Ishinomaki Senshu University
2023
Hokkaido University
2013-2021
The University of Tokyo
2013
Japan Fisheries Research and Education Agency
2013
Abstract. Chromophoric dissolved organic matter (CDOM) ubiquitously occurs in marine environments and plays a significant role the biogeochemical cycles. Basin scale distributions of CDOM have recently been surveyed global ocean indicate that quantity quality oceanic are mainly controlled by situ production photobleaching. However, factors controlling spectral parameters UV region, i.e., slope determined at 275–295 nm (S275–295) ratio two (SR); S275–295 to S350–400, not well documented. To...
Abstract This work presents the results of physical and biological investigations at 27 biogeochemical stations early winter sea ice in Ross Sea during 2017 PIPERS cruise. Only two similar cruises occurred past, 1995 1998. The year was a specific year, that growth Central considerably delayed, compared to previous years. These conditions resulted lower thicknesses Chl- burdens, as those observed cruises. It also different structure sympagic algal community, unusually dominated by Phaeocystis...
The seasonal biological drawdown of the partial pressure CO2 (pCO2) in surface waters Oyashio region western subarctic Pacific is one greatest among world's oceans. This attributable to spring diatom blooms. Transparent exopolymer particles (TEPs) are known affect efficiency carbon pump, and higher TEP levels frequently associated with massive blooms.However, dynamics remain unclear. study investigates distribution from three cruises during bloom periods 2010 2011. concentrations varied -1...
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...
Although much attention has been paid to describing the distribution of oceanic dimethyl sulfide (DMS) concentrations, establishing robust relationships between DMS concentrations and biological, physical, chemical variables is still challenging. Previous studies have proposed semiempirical parameterizations by combining multiple physical biogeochemical parameters better understand reproduce global sea surface DMS. However, none these parameterization schemes could reconcile regionally...
Abstract We elucidated the effects of snow and remineralization processes on nutrient distributions in multi‐year landfast sea ice (fast ice) Lützow‐Holm Bay, East Antarctica. Based sea‐ice salinity, oxygen isotopic ratios, thin section analyses, we found that fast grew upward due to year‐by‐year accumulation snow. Compared seawater origin, concentrations shallow were low replacement by clean fresh In deeper origin (the lower half column), was dominated degradation organic matter. By...
Abstract. We conducted repetitive observations in Funka Bay, Hokkaido, Japan, on 15 February, 4 and March, 14 April 2019. The diatom spring bloom peaked March started declining March. Bay winter water remained below 30 m depth, which was the surface mixed-layer dark-layer depth (0.1 % of photosynthetically active radiation, PAR, depth) In subsurface layer at depths 30–50 m, concentrations NO3-, PO43-, Si(OH)4 decreased by half between these dates, even dark. Incubation experiments using...
An atmosphere-sea ice-ocean interaction study was conducted at the Saroma-ko Lagoon, Hokkaido, Japan from 27 February to 9 March 2021. Air-sea ice CO2 flux measurements were by eddy covariance and chamber methods together with meteorological observations. Sea cores collected understand between atmosphere under-ice water respect fluxes of heat biogeochemical components. Physical parameters such as temperature, salinity, structure, environmental DNA, concentrations gases, nutrients, trace...
Abstract Sea ice, which forms in polar and nonpolar areas, transmits light to ice-associated (sympagic) algal communities. To noninvasively study the distribution of sea-ice algae, empirical relations estimate its biomass from under-ice hyperspectral irradiance have been developed Arctic Antarctica but lack for regions. This examines relationships between normalised difference indices (NDI) calculated transmittance sympagic Saroma-ko Lagoon. We analysed physico-biogeochemical properties snow...
Abstract The surface ocean is an important source of longer-lived volatile organic iodine compounds, such as methyl and ethyl iodide. However, their production in deep waters poorly constrained. Here, we combine shipborne seawater sediment core analyses to investigate the temporal vertical distribution iodide concentrations Bering Chukchi Seas July 2017 2018, Funka Bay, Japan, between March 2018 December 2019. We find highest porewaters at surface. In bottom strongly increased following...
Abstract. Chromophoric dissolved organic matter (CDOM) ubiquitously occurs in marine environments and plays a significant role the biogeochemical cycles. Basin scale distributions of CDOM have recently been surveyed global ocean indicate that quantity quality oceanic are mainly controlled by situ production photo-degradation. However, factors controlling spectral parameters at UV region, i.e., slope determined 275–295 nm (S275–295) ratio two (SR; S275–295 to S350–400), not well documented....
We conducted shipboard observations in Funka Bay, Hokkaido, Japan, 2015, 2016 and 2019 to observe temporal variations of isoprene (C5H8) concentration water sediment. found increases C5H8 concentrations below within the euphotic zone, which were associated with chl-a peaks changes nutrient dissolved oxygen (DO). a peak subsurface layer zone at 20 – 30 m depth May June that coincided decrease DO, suggesting there was net consumption. hypothesize rapid cycle regenerated production early summer...
We investigated the growth, thermotolerance, and fatty acid composition of green alga Desmodesmus sp., which was isolated from a freshwater puddle in Ibaraki, Japan. Incubation experiments on strain were performed at range temperatures (20–40°C) with continuous illumination (110 µmol photons m−2 s−1) nutrient-replete medium. High specific growth rates 1.14–1.62 day−1 observed 20–35°C, but declined to 0.59 40°C. Lipid contents 13.2%–14.4% (% dry weight) 20–35°C increased 21.3% Some microalgae...
Abstract. We conducted time-series observations in Funka Bay, Hokkaido, Japan, from 15 February to 14 April 2019. The diatom spring bloom peaked on 4 March and started declining March. Bay winter water remained below 30-m depth, which was the surface mixed-layer dark-zone depths both dates. At of 30–50 m, concentrations NO3–, PO43–, Si(OH)4 decreased by half between these dates even darkness. Incubation experiments using Thalassiosira nordenskioeldii showed that this could consume nutrients...