Article
Engineering, Marine
Bing Yang, Po Hu, Yijun Hou
Summary: In November 2017, the semidiurnal internal tides on the continental slope of the southeastern East China Sea exhibited abrupt enhancement, primarily due to the intensification of the coherent semidiurnal internal tides. The meandering and abrupt intrusion of the Kuroshio mainstream were related to the variations in the semidiurnal internal tides.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2022)
Article
Geochemistry & Geophysics
Hongxiang Guan, Lei Liu, Yu Hu, Sanzhong Li, Niu Li, Zhilei Sun, Nengyou Wu, Ian Somerville
Summary: This study investigates the mechanisms and parameters of past and current methane releases in the Okinawa Trough through comprehensive analysis of a piston core. The research also provides evidence for the response of gas hydrates in the trough to environmental changes.
Article
Engineering, Marine
Zhiling Ouyang, Ze Liu, Yijun Hou
Summary: The vertical structure and seasonal variability of shear on the southwestern continental slope of the East China Sea were analyzed using nearly three years of mooring ADCP data. The dominant components in the local shear field were the sub-inertial currents, near-inertial waves, and diurnal, semidiurnal, and tridiurnal internal tides. The shear exhibited a surface-intensified pattern with high values in the upper 200 m. Seasonal variations in shear were influenced by the meander of the Kuroshio mainstream and the Kuroshio intrusion. The shear efficiency of different internal tides varied due to their dominant modes.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2022)
Article
Oceanography
Xuan Cui, Dezhou Yang, Chaojiao Sun, Xingru Feng, Guandong Gao, Lingjing Xu, Baoshu Yin
Summary: A modified analytical solution was developed to simulate the flow pattern of the Kuroshio intrusion northeast of Taiwan, maintaining horizontal momentum balance. The new model accurately predicts the direction of the Kuroshio intrusion and aligns well with observational data, offering potential applications in regions with different flow patterns.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2021)
Article
Environmental Sciences
Juntian Chen, Xiao-Hua Zhu, Hua Zheng, Min Wang
Summary: Submesoscale processes in the ocean were investigated using numerical simulations in the East China Sea. It was found that the western boundary jet served as an important energy reservoir, and submesoscale footprints were observed in the continental slope and lee area of the Tokara Strait.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Geosciences, Multidisciplinary
Yi Wei, Ruibin Ding, Daji Huang, Jiliang Xuan, Hongliang Li, Jingjing Zhang, Xiao Ma, Feng Zhou, Jianfang Chen
Summary: The interannual sea surface temperature trend in the East China Sea (ECS-Kuroshio) differs significantly from that of the ECS-shelf region. Observational temperature data from 1982 to 2014 indicate that the upstream ECS-Kuroshio shows an opposite temperature trend to the downstream, creating a horizontal dipole structure. The variability in upwelling in the upstream ECS-Kuroshio is the main factor influencing this distinct temperature trend, which can be transported downstream through horizontal advections.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Environmental Sciences
Shou-En Tsao, Po-Yen Shen, Chun-Mao Tseng
Summary: This study investigated a nine-year time series data from 2010-2018 near the East China Sea, showing significantly greater trends of surface seawater pCO2 and pH compared to other oceanic time series. Mechanistic analysis revealed that seawater warming caused rapid increases in pCO2 and acidification, leading to a decline in CO2 uptake through air-sea exchange. The results suggest that rapidly warming boundary currents could result in an elevated pCO2 trend and a gradual reduction in oceanic CO2 uptake.
MARINE POLLUTION BULLETIN
(2023)
Article
Geosciences, Multidisciplinary
Dehui Qiao, Yasong Wang, Jianchun Yu, Bilin Liu, Jianqiang Wu, Huangmin Ge, Yuli Wei, Yunping Xu
Summary: Cross-shelf transport plays a significant role in marine carbon cycles. This study examined the concentration and optical composition of dissolved organic matter (DOM) in surface water samples collected from the East China Sea to the Okinawa Trough. The study found that compared to the Okinawa Trough, the East China Sea had higher concentrations of dissolved organic carbon and different optical parameters. The distribution of fluorescence components varied with the regions. Additionally, it was observed that DOM is well mixed in the East China Sea shelf but has limited transport across the Okinawa Trough.
JOURNAL OF MARINE SYSTEMS
(2023)
Article
Environmental Sciences
Qian Xu, Shengqiang Wang, Chiho Sukigara, Joaquim Goes, Helga do Rosario Gomes, Takeshi Matsuno, Yuanli Zhu, Yongjiu Xu, Jutarak Luang-on, Yuji Watanabe, Sinjae Yoo, Joji Ishizaka
Summary: The vertical distribution of phytoplankton composition in the East China Sea and Tsushima Strait varies greatly in regions with intersecting Changjiang River diluted water, Kuroshio water, and Tsushima water. Different phytoplankton groups dominate in different water masses, correlating with water property and nutrient concentration. The in-situ multiple excitation fluorometer proves to be a powerful tool for estimating high-resolution vertical profiles of phytoplankton groups in marine environments.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Engineering, Marine
Chen Dai, Shu Gao, Yongzhan Zhang, Fei Xia, Dandan Wang
Summary: In this study, the stratigraphic and chronological framework of the paleo-Changjiang River delta during the MIS 3 period was reconstructed based on high-resolution seismic profiles and borehole data. The results revealed a large-scale paleodeltaic complex formed during MIS 3, providing insights into the relationship between delta formation and sea-level changes and sediment supply.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2023)
Article
Environmental Sciences
Jiwon Kang, Hanna Na
Summary: This study investigated the long-term variability of Kuroshio shelf intrusion (KSI) northeast of Taiwan and its relationship with current and temperature variability in the East China Sea (ECS). The results showed that the KSI had significant changes in the 2000s, while it was relatively stable in the 1990s and 2010s, accompanied by a westward shift of the Kuroshio axis and warming.
FRONTIERS IN MARINE SCIENCE
(2022)
Article
Meteorology & Atmospheric Sciences
Zhiwei He, Dezhou Yang, Yonggang Wang, Baoshu Yin
Summary: In this study, the 4D-Var data assimilation technique is applied to the East China Sea using the ROMS model, allowing for optimization of initial conditions, boundary conditions, and surface forcing. The impact of tidal forcing on the simulation results is evaluated, as well as the contributions of different types of observations. The study highlights the importance of accurately capturing tidal processes in the modeling of the East China Sea.
Article
Environmental Sciences
Wentao Wang, Zhiming Yu, Xiuxian Song, Lianbao Chi, Peng Zhou, Zaixing Wu, Yongquan Yuan
Summary: This study investigated the seasonal source and contributions of internal decomposition of organic matter (OM) in the Kuroshio Subsurface Water (KSSW) for hypoxia formation in the East China Sea (ECS). The results showed that in June, N-2 fixation signals related to decomposed OM were apparent in the southern ECS, while terrestrial input signals were revealed in the northern ECS and most of the ECS in October. The terrestrial input contributed almost equally to the development of ECS hypoxia as compared to marine sources, indicating the importance of understanding eutrophication and oceanic circulation in hypoxia formation.
MARINE POLLUTION BULLETIN
(2022)
Article
Environmental Sciences
Fenfen Wang, Wu Men, Tao Yu, Jiang Huang, Jianhua He, Jing Lin, Feng Lin, Fangfang Deng
Summary: A study investigated the long-term impact of the Fukushima nuclear power plant accident on the South China Sea and the East China Sea. It was found that radioactive cesium isotopes from the accident intruded into these areas in 2013 and reached a peak in 2014. This intrusion was caused by the formation, subduction, and transport of subtropical and central mode water, which carried the radioactive cesium from the high-latitude open ocean to the low-latitude western boundary area, and then entered the South China Sea and the East China Sea through the Kuroshio Current.
Article
Geochemistry & Geophysics
Jianjun Zou, Xuefa Shi, Aimei Zhu, Yuan-Pin Chang, Min-Te Chen, Ruxi Dou
Summary: The continental margin plays a major role as a depocenter for terrigenous sediments in the world ocean, influenced by complex interactions between land and sea. Studies have shown dynamic changes in sediment compositions and terrigenous deposition patterns in the central Okinawa Trough over glacial-interglacial cycles, mainly sourced from Taiwanese rivers, the Yangtze River, and the Yellow River. The discovery of a Negative Ce Anomaly Event in the central Okinawa Trough attributed to suboxic conditions and depleted Ce-bearing sediments highlights the impact of various factors such as eustatic sea level changes and East Asian summer monsoon on deposition patterns.
Article
Geography, Physical
M. Civel-Mazens, X. Crosta, G. Cortese, E. Michel, A. Mazaud, O. Ther, M. Ikehara, T. Itaki
Summary: The oceanography of the western Indian sector of the Southern Ocean is complex due to the presence of subantarctic islands and plateaus. New sea-surface and sub-surface temperature data from cores covering the last 40,000 years reveal past oceanographic changes in the Kerguelen Islands region. The study suggests that surface conditions in the Subantarctic Zone of the Kerguelen Islands are influenced by the migration of Southern Ocean hydrological fronts and the Agulhas (Return) Current.
QUATERNARY SCIENCE REVIEWS
(2021)
Article
Geosciences, Multidisciplinary
Kentaro Izumi, Yuki Haneda, Yusuke Suganuma, Makoto Okada, Yoshimi Kubota, Naohisa Nishida, Moto Kawamata, Takuya Matsuzaki
Summary: This study investigated the Chiba composite section in central Japan through multiple sedimentological and geochemical analyses to establish high-resolution chemostratigraphy and reconstruct the paleoenvironments in detail. The results showed changes in organic matter sources and mixing ratios of marine vs. terrestrial organic matter at different Marine Isotope Stages, indicating variability in environmental conditions over time.
PROGRESS IN EARTH AND PLANETARY SCIENCE
(2021)
Article
Geosciences, Multidisciplinary
Yusuke Suganuma, Makoto Okada, Martin J. Head, Koji Kameo, Yuki Haneda, Hiroki Hayashi, Toshiaki Irizuki, Takuya Itaki, Kentaro Izumi, Yoshimi Kubota, Hiroomi Nakazato, Naohisa Nishida, Masaaki Okuda, Yasufumi Satoguchi, Quentin Simon, Yoshihiro Takeshita
Summary: The Chiba composite section in Japan has been ratified as the GSSP for defining the Chibanian Stage/Age and Middle Pleistocene Subseries/Subepoch. This section contains well-preserved markers such as pollen, marine micro-and macrofossils, paleomagnetic polarity boundaries, and tephra beds, providing a robust chronostratigraphic framework.
Article
Ecology
Takeshige Ishiwa, Yuki Tokuda, Takuya Itaki, Satoshi Sasaki, Yusuke Suganuma, Shintaro Yamasaki
Summary: The sediments around Antarctica provide valuable records of sea-level changes, but accessing field-based evidence of ice-sheet and sea-level change is challenging. Researchers used a portable sonar system to collect baseline data in East Antarctica for reconstructing sea-level and ice-sheet changes.
Article
Geosciences, Multidisciplinary
Yoshimi Kubota, Yuki Haneda, Koji Kameo, Takuya Itaki, Hiroki Hayashi, Kizuku Shikoku, Kentaro Izumi, Martin J. Head, Yusuke Suganuma, Makoto Okada
Summary: The fluctuating boundary between the Kuroshio and Oyashio currents in the western North Pacific significantly affects the climate of East Asia. The reconstruction of paleoceanography from Marine Isotope Stages 20-18 shows that the dominant seasonal trend is influenced by the winter monsoon system.
PROGRESS IN EARTH AND PLANETARY SCIENCE
(2021)
Article
Geography, Physical
M. Civel-Mazens, X. Crosta, G. Cortese, E. Michel, A. Mazaud, O. Ther, M. Ikehara, T. Itaki
Summary: In the Southern Ocean, climate-driven latitudinal migrations of the Antarctic Circumpolar Current frontal system impact ocean circulation and primary productivity. The Antarctic Polar Front's migrations influence nutrient redistribution, biodiversity, and the soft tissue carbon pump in the modern Southern Ocean.
GLOBAL AND PLANETARY CHANGE
(2021)
Article
Geosciences, Multidisciplinary
Naohisa Nishida, Takuya Itaki, Atsuko Amano, Hajime Katayama, Taichi Sato, Dorrik Stow, Uisdean Nicholson
Summary: This paper documents a new area of contourite-controlled sedimentation in the NW Pacific Ocean, known as the Ryukyu Sand Sheet. The sand sheet is primarily composed of fine-grained sands and is formed under the influence of three principal current systems and complex seafloor topography.
Article
Geosciences, Multidisciplinary
Takuya Itaki, Sakura Utsuki, Yuki Haneda, Kentaro Izumi, Yoshimi Kubota, Yusuke Suganuma, Makoto Okada
Summary: Marine isotope stage (MIS) 19 is an important period for understanding interglacial climate changes. A high-resolution radiolarian record from the Chiba composite section in Japan reveals millennial-scale oscillations in the Kuroshio warm and Oyashio cold currents. These oscillations are related to changes in nutrient and photic environments along the Kuroshio-Oyashio boundary zone. Similar climatic changes have also been observed in precipitation records from central Italy.
PROGRESS IN EARTH AND PLANETARY SCIENCE
(2022)
Article
Geography, Physical
T. Tamura, T. Ishiwa, Y. Tokuda, T. Itaki, S. Sasaki, Y. Suganuma
Summary: The Late Pleistocene sea-level history of Antarctica is crucial for understanding the response of icesheets to changing climates. This study explored the applicability of luminescence dating to coastal sediments in Lutzow-Holm Bay and found two episodes of sea-level highstand. Further application of this dating method can refine our understanding of the late Quaternary relative sea-level history in East Antarctica.
QUATERNARY GEOCHRONOLOGY
(2022)
Article
Geochemistry & Geophysics
Jiaxi Li, Toshitsugu Yamazaki, Yoichi Usui, Takuya Sagawa, Yoshimi Kubota, Junichiro Kuroda
Summary: Marine sediments can preserve continuous paleomagnetic intensity records. Compositional variations of magnetic mineral assemblages may hinder extraction of reliable relative paleointensity (RPI) records. This study investigates a sediment core from the western equatorial Pacific Ocean and finds that biogenic magnetite contributes to RPI records with lower efficiency than unprotected terrigenous magnetic minerals.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geosciences, Multidisciplinary
Andros Daniel Cruz Salmeron, Hideko Takayanagi, Shigeyuki Wakaki, Tsuyoshi Ishikawa, Toshihiro Miyajima, Hitomi Wakaki, Takuya Itaki, Yasufumi Iryu
Summary: This study investigated the water-mass structure on the Okinawa Trough and Pacific sides of the southern Ryukyu Island Arc using isotope compositions and physical properties of seawater. The results showed that the Okinawa Trough side has lower values due to continental/island material inputs, and the Nd behavior of seawater is primarily affected in certain subareas.
PROGRESS IN EARTH AND PLANETARY SCIENCE
(2022)
Article
Paleontology
M. Civel-Mazens, K. A. Lawler, M. Ikehara, T. Itaki, G. Cortese, X. Crosta, V. Lowe
Summary: This study aims to reconstruct subsurface temperatures in the Southern Ocean using radiolarian data. The results suggest a positive correlation between radiolarian assemblages and summer temperatures at 200 m, and common temperature reconstruction methods show excellent performance.
MARINE MICROPALEONTOLOGY
(2023)
Article
Multidisciplinary Sciences
Mutsumi Iizuka, Osamu Seki, David J. Wilson, Yusuke Suganuma, Keiji Horikawa, Tina van de Flierdt, Minoru Ikehara, Takuya Itaki, Tomohisa Irino, Masanobu Yamamoto, Motohiro Hirabayashi, Hiroyuki Matsuzaki, Saiko Sugisaki
Summary: Sedimentary records from offshore of the East Antarctic Ice Sheet provide evidence for two ice loss events during the Last Interglacial period, leading to elevated sea levels similar to the present day. Understanding Antarctic ice-sheet dynamics during this period can provide valuable insights for predicting future sea-level change. A high-resolution record from the Wilkes Subglacial Basin reveals fluctuations of the ice sheet, with thinning, melting, and potentially retreat during both early and late stages of the Last Interglacial.
NATURE COMMUNICATIONS
(2023)
Article
Geosciences, Multidisciplinary
Zhi Dong, Xuefa Shi, Jianjun Zou, Xinqing Zou, Muhong Chen, Qiang Zhang, Selvaraj Kandasamy, Chendong Ge, Ling Liu, Takuya Itaki, Fengdeng Shi, Yanguang Liu
