A5025667632- Marine and coastal ecosystems
- Oceanographic and Atmospheric Processes
- Arctic and Antarctic ice dynamics
- Marine Biology and Ecology Research
- Marine and fisheries research
- Isotope Analysis in Ecology
- Methane Hydrates and Related Phenomena
- Marine Bivalve and Aquaculture Studies
- Marine and coastal plant biology
- Water Quality Monitoring and Analysis
- Food Industry and Aquatic Biology
- Atmospheric and Environmental Gas Dynamics
- Marine and environmental studies
- Ocean Acidification Effects and Responses
- Cephalopods and Marine Biology
- Marine animal studies overview
- Microbial Community Ecology and Physiology
- Water Quality Monitoring Technologies
- Atmospheric chemistry and aerosols
- Geological Studies and Exploration
- Cryospheric studies and observations
- Arctic and Russian Policy Studies
- Geology and Paleoclimatology Research
- Indigenous Studies and Ecology
- Coral and Marine Ecosystems Studies
National Institute of Polar Research
2002-2024
The Graduate University for Advanced Studies, SOKENDAI
2006-2024
Research Organization of Information and Systems
2006-2024
Hokkaido University
2014-2023
Arctic Research Centre
2015-2020
Hakodate University
2007
Tokyo University of Marine Science and Technology
1997-2000
Phytoplankton are composed of diverse taxonomical groups, which manifested as distinct morphology, size and pigment composition. These characteristics, modulated by their physiological state, impact light absorption scattering, allowing them to be detected with ocean color satellite radiometry. There is a growing volume literature describing algorithms retrieve information on phytoplankton composition in the ocean. This synthesis provides review current methods simplified comparison...
Abstract We investigated 32 net primary productivity (NPP) models by assessing skills to reproduce integrated NPP in the Arctic Ocean. The were provided with two sources each of surface chlorophyll‐ a concentration (chlorophyll), photosynthetically available radiation (PAR), sea temperature (SST), and mixed‐layer depth (MLD). most sensitive uncertainties chlorophyll, generally performing better situ chlorophyll than satellite‐derived values. They much less PAR, SST, MLD, possibly due...
Abstract Saitoh, S-I., Mugo, R., Radiarta, I N., Asaga, S., Takahashi, F., Hirawake, T., Ishikawa, Y., Awaji, In, and Shima, S. 2011. Some operational uses of satellite remote sensing marine GIS for sustainable fisheries aquaculture. – ICES Journal Marine Science, 68: 687–695. An overview remote-sensing (SRS) applications in is presented, includes two case studies illustrating the societal benefits SRS. The first describes use satellite-based vessel monitoring systems (VMS) SRS data a...
Abstract Climate change impacts are pronounced at high latitudes, where warming, reduced sea-ice-cover, and ocean acidification affect marine ecosystems. We review climate on two major gateways into the Arctic: Bering Chukchi seas in Pacific Barents Sea Fram Strait Atlantic. present scenarios of how changes physical environment prey resources may commercial fish populations fisheries these high-latitude systems to help managers stakeholders think about possible futures. Predicted include...
Abstract. This study assesses the response of phytoplankton assemblages to recent climate change, especially with regard shrinking sea ice in northern Chukchi Sea western Arctic Ocean. Distribution patterns groups late summers 2008–2010 were analysed based on HPLC pigment signatures and, following four major algal inferred via multiple regression and cluster analyses: prasinophytes, diatoms, haptophytes dinoflagellates. A remarkable interannual difference distribution pattern was found basin...
Abstract Aim To investigate the species‐specific exposure and distributional responses of marine fish invertebrate taxa to rapidly shifting climate in Pacific Arctic, characterized by warming cooling episodes, over last 24 years. Location Arctic region, eastern Bering Sea Chukchi Sea. Methods We examined variations summer (June–July) habitat patterns 21 using multimodel ensemble predictions species distribution between 1993 2016. Using model outputs, we rates predicted (biotic velocities)...
Abstract. We analysed mooring and ship-based hydrographic biogeochemical data obtained from a Hope Valley biological hotspot in the southern Chukchi Sea. The moorings were deployed 16 July 2012 to 19 2014, captured during spring autumn blooms with high chlorophyll concentrations. Turbidity increased dissolved oxygen decreased bottom water at site before bloom, suggesting an accumulation of particulate organic matter its decomposition (nutrient regeneration) bottom. This event may have been...
Abstract A fixed‐point observation station was set up in the northern Chukchi Sea during autumn 2013, and for about 2 weeks conductivity‐temperature‐depth (CTD)/water samplings (6 h) microstructure turbulence measurements (2 to 3 times a day) were performed. This enabled us estimate vertical nutrient fluxes impact of different types turbulent mixing on biological activity. There have been no such observations this region, where incoming low‐salinity water from Pacific Ocean, river water,...
A multiple year‐round study of atmospheric dimethyl sulfide (DMS) (from December 1998 to April 2003) as well sulfur‐derived aerosols (methanesulfonic acid (MSA) and non‐sea‐salt sulfate) March 1991 February was conducted at Dumont d'Urville, coastal Antarctica. The three species exhibit a seasonal cycle characterized by maxima in midsummer (January). Whereas the interannual variability winter levels remains low, strong is shown summer, particularly for DMS MSA, lesser extent sulfate. Over...
Abstract. Recent ocean warming and subsequent sea ice decline resulting from climate change could affect the northward shift of ecosystem structure in Chukchi Sea Bering shelf region (Grebmeier et al., 2006b). The size phytoplankton communities provides an index trophic levels that is crucial to understanding mechanisms underlying such changes their implications for future. This study proposes a new color algorithm deriving this characteristic by using region's optical properties. derivation...
The effects of El Nino–Southern Oscillation events on catches Bigeye Tuna (Thunnus obesus) in the eastern Indian Ocean (EIO) off Java were evaluated through use remotely sensed environmental data (sea-surface-height anomaly [SSHA], sea-surface temperature [SST], and chlorophyll a concentration), catch data. Analyses conducted for period 1997–2000, which included 1997–98 Nino 1999–2000 La Nina events. empirical orthogonal function (EOF) was applied to examine oceanographic parameters...
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...
Abstract One of the most important breakthroughs in oceanography last 30 years was discovery that iron (Fe) controls biological production as a micronutrient, and our understanding Fe nutrient biogeochemical dynamics ocean has significantly advanced. In this review, we looked back both previous updated knowledge natural supply processes subarctic Pacific its impact on production. Although atmospheric dust been considered to be source affecting Pacific, other oceanic sources have discovered....
The flow of Pacific-origin water across the Chukchi Sea shelf impacts regional ecosystem in profound ways, yet two current branches on eastern that carry from Bering Strait to Barrow Canyon – Alaskan Coastal Current (ACC) and Central Channel (CC) Branch have not been clearly distinguished or quantified. In this study we use an extensive collection repeat hydrographic sections occupied at three locations shelf, together with data a climatology shipboard velocity data, accomplish this. were...
Abstract Hirawake, T., Shinmyo, K., Fujiwara, A., and Saitoh, S. 2012. Satellite remote sensing of primary productivity in the Bering Chukchi Seas using an absorption-based approach. – ICES Journal Marine Science, 69: . Ocean colour has been utilized for studying Arctic Ocean. However, phytoplankton chlorophyll a (Chl a) is not predicted accurately because interference coloured dissolved organic matter (CDOM) non-algal particles (NAP). To enhance estimation accuracy, model (ABPM) was applied...
Abstract. The size structure and biomass of a phytoplankton community during the spring bloom period can affect energy use higher-trophic-level organisms through predator–prey body relationships. timing sea ice retreat (TSR) also plays crucial role in seasonally ice-covered marine ecosystem, because it is tightly coupled with bloom. Thus, important to monitor temporal spatial distributions structure. Prior this study, an ocean colour algorithm was developed derive index FL, which defined as...
Remotely derived environmental variables, including sea surface height anomaly (SSHA), temperature (SST), chlorophyll-a (chl-a), eddy kinetic energy (EKE), mixed layer data set of argo float (MLD), Niño 3.4 index, and bigeye tuna catch for the period 1997–2008, were used to analyse ocean climate variability how they relate hotspots in eastern Indian Ocean off Java. The empirical orthogonal function (EOF) was performed obtain a more detailed structure spatio-temporal region. results showed...