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Partitioning and lateral transport of iron to the Canada Basin

Ana M. Aguilar-Islas, Robert Rember, Shigeto Nishino, Takashi Kikuchi, Motoyo Itoh
2013 Polar Science  
Grey bar shows depth influenced by the eddy (after Nishino et al., 2011a) .  ...  The grey oval indicates the approximate location of the warm-core (after Nishino et al., 2011a) . Bathymetric contours from 50 m to 4000 m are outlined.  ... 
doi:10.1016/j.polar.2012.11.001 fatcat:665fjpcyp5h6vgf4s25djsvbnm

Interannual variation in solar heating in the Chukchi Sea, Arctic Ocean

Yushiro Tsukada, Hiromichi Ueno, Naoki Ohta, Motoyo Itoh, Eiji Watanabe, Takashi Kikuchi, Shigeto Nishino, Kohei Mizobata
2018 Polar Science  
doi:10.1016/j.polar.2018.06.003 fatcat:s5j2l3xgdfahdcfckt4rmudaki

Prolonged aragonite undersaturation in bottom water of a biological hotspot in the Chukchi Sea, Arctic Ocean

Michiyo Yamamoto-Kawai, Takahisa Mifune, Takashi Kikuchi, Shigeto Nishino
2016 Biogeosciences Discussions  
Nishino et al. Fig. 2).  ...  The lowest Ωar was observed on 3 October 2012 in Hope Valley at 68ºN, in the dome-like structure of bottom water with low T, high S and low DO (Fig. 25 2; Nishino et al., 2016).  ... 
doi:10.5194/bg-2016-74 fatcat:f6iubf3sgrfzjjaixyr6d3iuaa

Low pCO2 under sea-ice melt in the Canada Basin of the western Arctic Ocean

Naohiro Kosugi, Daisuke Sasano, Masao Ishii, Shigeto Nishino, Hiroshi Uchida, Hisayuki Yoshikawa-Inoue
2017 Biogeosciences Discussions  
(Nishino et al., 2015) . The data used in this paper are available from the JAMSTEC Data Site for Research Cruises (http://www.godac.jamstec.go.jp/darwin/cruise/mirai/mr13-06_leg1/e).  ...  Nishino et al. (2013) also observed decreases in nitrate and chlorophyll in the 0 to 50 m depth layer in the Canada Basin during 2002-2010; they attributed these decreases to the decrease in inflow of  ... 
doi:10.5194/bg-2017-148 fatcat:ua6f7qi3bnfchoz6f5xqkjf3cm

Low pCO2 under sea-ice melt in the Canada Basin of the western Arctic Ocean

Naohiro Kosugi, Daisuke Sasano, Masao Ishii, Shigeto Nishino, Hiroshi Uchida, Hisayuki Yoshikawa-Inoue
2017 Biogeosciences  
Nishino et al. (2013) also observed decreases in nitrate and chlorophyll in the 0 to 50 m depth layer in the Canada Basin during 2002-2010; they attributed these decreases to the decrease in in-flow of  ...  measurements in the Chukchi Sea and the Canada Basin were made during cruise MR13-06 of the R/V Mirai conducted by the Japan Agency for Marine-Earth Science and Technology from 28 August to 6 October 2013 (Nishino  ... 
doi:10.5194/bg-14-5727-2017 fatcat:rciy5vzvbra37eligsz7pjcwwq

Joint index vector: a novel assessment measure for stratified medicine in patients with rheumatoid arthritis

Susumu Nishiyama, Tetsuji Sawada, Jinju Nishino, Shigeto Tohma
2018 Journal of Big Data  
Introduction Although it is difficult to forecast which joints will be involved or intact in patients with rheumatoid arthritis (RA) in the long term, the ability to predict the next-year distribution of affected joints for individual patients would be useful for choosing the correct therapeutic option. Abstract Objective: To predict the next-year status in patients with rheumatoid arthritis using big data. Methods: Joint index (JI) of upper/large (UL), upper/small (US), lower/large (LL), and
more » ... wer/small (LS) was calculated as the sum of tender and swollen joint counts divided by the number of evaluable joints in each region of interest. Joint index vector V (x, y, z) was defined as x = JI UL + JI US , y = JI LL + JI LS , and z = JI UL + JI LL − JI US − JI LS . Low disease activity was defined as |Vxy| (= √x 2 + y 2 ) ≤ 0.1. Patients with |Vxy| > 0.1 were further classified into three groups: evenly affected (EVN): |z| ≤ 0.2, small joint dominant (SML): z < − 0.2, and large joint dominant (LAR): z > 0.2. To predict the next-year V (x, y, z) of each patient, a transformation matrix was computed from the mean vectors of the EVN, SML, and LAR groups and their translation vectors. Results: |Vxy| was correlated with Simplified Disease Activity Index (SDAI) (r = 0.82). Z of mean vector increased as the disability index of the Health Assessment Questionnaire (HAQ-DI) and the Steinbrocker class worsened. The LAR group had the worst HAQ-DI and the second highest SDAI after those in the SML group. Positive predictive value and likelihood ratio in predicting the LAR group were 58.7% and 5.9, respectively. Likelihood ratio was greater with treatment, at 7.2, 7.4, and 8.6 when targeted patients were treated with methotrexate, biologics, and both drugs, respectively. Conclusions: Patients with high disease activity and poor functional state were predicted with high probability using joint index vectors.
doi:10.1186/s40537-018-0148-1 fatcat:plrkyo2id5eqfp3t3ywsleruwi

Impacts of Temperature, CO2, and Salinity on Phytoplankton Community Composition in the Western Arctic Ocean

Koji Sugie, Amane Fujiwara, Shigeto Nishino, Sohiko Kameyama, Naomi Harada
2020 Frontiers in Marine Science  
., 2014; Nishino et al., 2015; Fujiwara et al., 2018) .  ...  We applied the end-member values of SW, SIM, and OF used by Nishino et al. (2016) in their study of water mass characteristics in the Chukchi Sea.  ... 
doi:10.3389/fmars.2019.00821 fatcat:ddkcfg63zzawdkqf6tm63gqd34

Water mass characteristics and their temporal changes in a biological hotspot in the southern Chukchi Sea

Shigeto Nishino, Takashi Kikuchi, Amane Fujiwara, Toru Hirawake, Michio Aoyama
2016 Biogeosciences  
<p><strong>Abstract.</strong> We analysed mooring and ship-based hydrographic and biogeochemical data obtained from a Hope Valley biological hotspot in the southern Chukchi Sea. The moorings were deployed from 16 July 2012 to 19 July 2014, and data were captured during spring and autumn blooms with high chlorophyll <i>a</i> concentrations. Turbidity increased and dissolved oxygen decreased in the bottom water at the mooring site before the autumn bloom, suggesting an accumulation of particulate
more » ... organic matter and its decomposition (nutrient regeneration) at the bottom. This event may have been a trigger for the autumn bloom at this site. The bloom was maintained for 1 month in 2012 and for 2 months in 2013. The maintenance mechanism for the autumn bloom was also studied by hydrographic and biogeochemical surveys in late summer to autumn 2012 and 2013. Nutrient-rich water from the Bering Sea supplied nutrients to Hope Valley, although a reduction in nutrients occurred in 2012 by the influence of lower-nutrient water that would have remained on the Chukchi Sea shelf. In addition, nutrient regeneration at the bottom of Hope Valley could have increased nutrient concentrations and explained 60<span class="thinspace"></span>% of its nutrient content in the bottom water in the autumn of 2012. The high nutrient content with the dome-like structure of the bottom water may have maintained the high primary productivity via the vertical nutrient supply from the bottom water, which was likely caused by wind-induced mixing during the autumn bloom. Primary productivity was 0.3<span class="thinspace"></span>g<span class="thinspace"></span>C<span class="thinspace"></span>m<sup>−2</sup><span class="thinspace"></span>d<sup>−1</sup> in September 2012 and 1.6<span class="thinspace"></span>g<span class="thinspace"></span>C<span class="thinspace"></span>m<sup>−2</sup><span class="thinspace"></span>d<sup>−1</sup> in September 2013. The lower productivity in 2012 was related to strong stratification caused by the high fraction of surface sea ice meltwater.</p>
doi:10.5194/bg-13-2563-2016 fatcat:ba7jz7gubrfbdne32l3hx2ydsm

Biogeochemical Anatomy of a Cyclonic Warm-Core Eddy in the Arctic Ocean

Shigeto Nishino, Yusuke Kawaguchi, Amane Fujiwara, Takuhei Shiozaki, Michio Aoyama, Naomi Harada, Takashi Kikuchi
2018 Geophysical Research Letters  
This ammonium-rich water was likely derived from the bottom of the Chukchi shelf during summer to autumn (Nishino et al., 2005) .  ...  Detailed descriptions of data acquisition during the cruise are presented in the supporting information (Text S1) and the cruise report (Nishino, 2015) .  ... 
doi:10.1029/2018gl079659 fatcat:cvchqjmy2ng6dmkqq3h6nqfrse

Seasonal variation of CaCO3 saturation state in bottom water of a biological hotspot in the Chukchi Sea, Arctic Ocean

Michiyo Yamamoto-Kawai, Takahisa Mifune, Takashi Kikuchi, Shigeto Nishino
2016 Biogeosciences  
Details of other sensor and mooring observations are described in Nishino et al. (2016) .  ...  Note that a correction of −69 µmol kg −1 applied for the third mooring data in Nishino et al. (2016) was found to be due to an artificial error in conversion of original sensor output to concentration  ... 
doi:10.5194/bg-13-6155-2016 fatcat:biy553pbsjhsdiblj2mwcmx4hq

Incorporation of satellite-derived thin-ice data into a global OGCM simulation

Takahiro Toyoda, Katsushi Iwamoto, L. Shogo Urakawa, Hiroyuki Tsujino, Hideyuki Nakano, Kei Sakamoto, Goro Yamanaka, Yoshiki Komuro, Shigeto Nishino, Jinro Ukita
2019 Climate Dynamics  
The salinity changes were further evaluated by using CTD observations from R/V Mirai cruises conducted in ice-free regions of the Pacific section of the Arctic Ocean (e.g., Nishino et al. 2013) .  ...  ., Nishino et al. 2013) were provided by the Japan Agency for Marine-Earth Science and Technology. 7 These in situ salinity observations as well as the MIMOC mixed-layer depths (MLDs) were used for validation  ... 
doi:10.1007/s00382-019-04979-8 fatcat:d55vjfxf5be6hpnykrrcxuvstq

Enhanced role of eddies in the Arctic marine biological pump

Eiji Watanabe, Jonaotaro Onodera, Naomi Harada, Makio C. Honda, Katsunori Kimoto, Takashi Kikuchi, Shigeto Nishino, Kohei Matsuno, Atsushi Yamaguchi, Akio Ishida, Michio J. Kishi
2014 Nature Communications  
The future conditions of Arctic sea ice and marine ecosystems are of interest not only to climate scientists, but also to economic and governmental bodies. However, the lack of widespread, year-long biogeochemical observations remains an obstacle to understanding the complicated variability of the Arctic marine biological pump. Here we show an early winter maximum of sinking biogenic flux in the western Arctic Ocean and illustrate the importance of shelf-break eddies to biological pumping from
more » ... ide shelves to adjacent deep basins using a combination of year-long mooring observations and three-dimensional numerical modelling. The sinking flux trapped in the present study included considerable fresh organic material with soft tissues and was an order of magnitude larger than previous estimates. We predict that further reductions in sea ice will promote the entry of Pacific-origin biological species into the Arctic basin and accelerate biogeochemical cycles connecting the Arctic and subarctic oceans.
doi:10.1038/ncomms4950 pmid:24862402 pmcid:PMC4055836 fatcat:yxvugg66ojfg7krxuovxrxoi6e

Upper Ocean Heat Observation using UpTempO buoys during RV Mirai Arctic cruise MR14-05

Yusuke Kawaguchi, Michael Steele, Kristina Colburn, Shigeto Nishino, Kazuhiro Oshima
2015 JAMSTEC Report of Research and Development  
influenced by the westward flow of Beaufort Gyre (BG), located to the north of the Alaskan continental shelf (McPhee 2013; Brugler et al. 2014; Nishino et al. 2011).  ...  velocity profiler's trajectories in October 2013 (deployed off the Barrow Canyon during MR13-06) similarly indicated the delay of ice formation along the pathway of the BG's westward current (Kawaguchi and Nishino  ... 
doi:10.5918/jamstecr.21.1 fatcat:twxlfqfkzfhsdo4t3ev2276yz4

Sediment-Associated Phytoplankton Release From the Seafloor in Response to Wind-Induced Barotropic Currents in the Bering Strait

Hiroto Abe, Makoto Sampei, Toru Hirawake, Hisatomo Waga, Shigeto Nishino, Atsushi Ooki
2019 Frontiers in Marine Science  
The southeastern Chukchi Sea, which is located in the downstream region of the Bering Strait throughflow, receives horizontal inputs of particulate organic matter and nutrients from the south Nishino  ...  travel distance using both the residence time and current of 100 cm s −1 reveals that the diatoms can travel for at least 100 km, thus reaching to biological hotspots in the southeastern Chukchi Sea Nishino  ... 
doi:10.3389/fmars.2019.00097 fatcat:mjvom3dpazf7rnjx6yuaaxka7y

Changes in phytoplankton community structure during wind-induced fall bloom on the central Chukchi shelf

Amane Fujiwara, Shigeto Nishino, Kohei Matsuno, Jonaotaro Onodera, Yusuke Kawaguchi, Toru Hirawake, Koji Suzuki, Jun Inoue, Takashi Kikuchi
2018 Polar Biology  
The SWE enhanced internal waves and wind-induced mixing, which weakened the stratification Nishino et al. 2015) .  ...  Briefly, the SWE magnitude was sufficiently large to induce internal waves and weaken the vertical stratification Nishino et al. 2015) .  ... 
doi:10.1007/s00300-018-2284-7 fatcat:zqo667fnmjeh7igx5up2u2kpri
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