Article
Multidisciplinary Sciences
Karla P. Knudson, Ana Christina Ravelo, Ivano W. Aiello, Christina P. Knudson, Michelle K. Drake, Tatsuhiko Sakamoto
Summary: Studies of laminated sediments from the subarctic Pacific over the past 1.2 million years indicate that hypoxic events were common during the Pleistocene, typically occurring during interglacial climates, high sea levels, and increased nitrate utilization, rather than being directly associated with deglaciations. The research suggests that hypoxia was primarily driven by high productivity resulting from iron fertilization facilitated by redox-remobilized iron from flooded continental shelves.
Article
Geosciences, Multidisciplinary
Ekaterina Ovsepyan, Elena Ivanova, Martin Tetard, Lars Max, Ralf Tiedemann
Summary: The study semi-quantitatively estimated the dissolved oxygen concentrations in the western Bering Sea during the deglaciation, revealing distinct changes in oxygen content in intermediate and deep waters during different periods. The variations in oxygen concentrations in the intermediate depths were linked to the North Atlantic climate, while those in the deep waters were associated with changes in the circulation of southern-sourced waters and amplified by Northern Hemisphere climate warming. The region of the Bering Sea and sea-level oscillations significantly contributed to the magnitude of oxygenation changes during the last deglaciation, with more pronounced changes observed in the Bering and Okhotsk marginal seas compared to the open-ocean continental margin and abyssal settings of the North Pacific.
FRONTIERS IN EARTH SCIENCE
(2021)
Article
Geography, Physical
Smita N. Naik, Sushant S. Naik, Yair Rosenthal, Vincent Clementi
Summary: By analyzing samples of epibenthic foraminifera from the eastern Arabian Sea, this study reveals the variations of stored CO2 and carbonate ion in deep waters from the Last Glacial Maximum to the Holocene. The rise in CO2 and carbonate ion during the deglaciation and the mid-Holocene is attributed to the release of glacial CO2 from deep waters through the Southern Ocean and via intermediate waters of the eastern Arabian Sea.
QUATERNARY SCIENCE REVIEWS
(2023)
Article
Geochemistry & Geophysics
Kumari Nisha, Sushant Suresh Naik, Pankaj Kumar, Barnita Banerjee, P. B. Rama Murty
Summary: This study investigates the ventilation changes in deep waters of the northern Indian Ocean over the past 25 kyr BP, and finds that a greater proportion of CO2-rich Antarctic Bottom Water (AABW) was present during the Last Glacial Maximum (LGM) and Heinrich Stadial (HS1). Poor ventilation during the last glaciation indicates that the northern Indian Ocean was part of the glacial carbon pool, while improved ventilation during the Bolling-Allerod (B-A) suggests the inflow of North Atlantic Deep Water (NADW) caused degassing from the northern Indian Ocean. Overall, this study supports the role of the Southern Ocean in modulating atmospheric CO2 variations during the last deglaciation.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geography, Physical
Ting Chen, Qingsong Liu, Xiaodan Wang
Summary: The study focuses on the ocean ventilation change in the subarctic Pacific Ocean and its impact on the marine ecosystem. By analyzing the element and isotope data from ODP Site 882, it is found that the intensity of deep/bottom water ventilation is correlated with the sea surface temperature gradient over the past millions of years.
GLOBAL AND PLANETARY CHANGE
(2022)
Article
Geography, Physical
Xuefa Shi, Shengfa Liu, Xu Zhang, Yuchen Sun, Peng Cao, Hui Zhang, Xiaoyan Li, Shan Xu, Shuqing Qiao, Somkiat Khokiattiwong, Narumol Kornkanitnan, Gerrit Lohmann
Summary: This study reconstructs sea surface temperature (SST) and seawater oxygen isotope (δ O-18(sw)) in the central Andaman Sea over the past 26,000 years to investigate the driving mechanism of millennial-scale climate changes in the tropical Indian Ocean. The results show that the changes in SST and δ O-18(sw) during the last deglaciation are associated with the Asian monsoon system, which is influenced by North Atlantic climate changes. The strengthening of the East Asian winter monsoon and the weakening of the Indian summer monsoon play a crucial role in the millennial-scale hydroclimate changes in the tropical Indian Ocean.
QUATERNARY SCIENCE REVIEWS
(2022)
Article
Geosciences, Multidisciplinary
S. Z. Mark, M. B. Abbott, B. A. Steinman, A. Fernandez, E. K. Wise, M. K. Walsh, C. Whitlock
Summary: The study presents oxygen isotope and charcoal accumulation records from lakes in eastern Washington, with sufficient resolution to compare with tree-ring records and meteorological data. The findings show that the wetter conditions during the Medieval Climate Anomaly (MCA) compared to the Little Ice Age (LIA) were reflected in the oxygen isotope measurements. Additionally, the charcoal records indicate increased fire activity during the LIA. The study also reveals increased hydroclimate variability after 1250 CE in western North America.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geography, Physical
Fang Qian, Fengming Chang, Tiegang Li, Anchun Li, Hanjie Sun, Junru Zhang
Summary: Thermocline conditions in the tropical western Pacific play a critical role in global climate evolution. However, the long-term changes in thermocline hydrology in the subtropical northwestern Pacific and its connection to the tropical Pacific are still unclear. Based on planktonic foraminiferal Mg/Ca and delta(18O), this study reconstructed the temperature and salinity of thermocline water in the subtropical northwestern Pacific since the last deglaciation. The results showed a close relationship between thermocline hydrology and changing conditions in the tropical western Pacific, indicating a significant role of the ENSO-like process in regulating thermocline dynamics.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2023)
Article
Geosciences, Multidisciplinary
C. M. Darvill, B. Menounos, B. M. Goehring, A. J. Lesnek
Summary: This study reports 20 Be-10 exposure ages from glacial erratics and bedrock on the west coast of British Columbia, Canada, contributing to the existing chronologies of Cordilleran Ice Sheet retreat along approximately 600 km of coastal North America. The data show that the western ice limit reached the present coast by 18-16 ka then slowed its retreat for around 4,000 years until 14-13 ka. The initial retreat is attributed to destabilization and grounding line retreat caused by rising sea level and/or ocean warming in the northern Pacific. Despite increasing temperatures, the subsequent stability of the ice sheet at the present coastal margin is likely due to the transition from marine to terrestrial margins.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Energy & Fuels
Alexandra R. Rempel, Jackson Danis, Alan W. Rempel, Michael Fowler, Sandipan Mishra
Summary: Extreme heat events are increasing in frequency and severity, leading to health risks in the Pacific Northwest and similar climates. Passive cooling strategies such as shading and natural ventilation have shown promise in reducing indoor temperatures and active cooling loads during extreme heat.
Article
Energy & Fuels
Alexandra R. Rempel, Jackson Danis, Alan W. Rempel, Michael Fowler, Sandipan Mishra
Summary: The study found that passive cooling strategies such as shading and natural ventilation can significantly reduce indoor temperatures, decrease the time spent above danger threshold during extreme heat events, and provide thermal relief without using active cooling equipment, reducing cooling loads by up to 80%.
Article
Geology
Yuxin Zhou, Jerry McManus
Summary: This paper investigates in detail a layer of red sediments deposited along the northwestern Atlantic Ocean 125,000 years ago. It finds that this deposit was a glacial outburst event similar to the one that occurred 8,200 years ago. The freshwater discharge associated with this event may explain several global abrupt changes, including a reduction in North Atlantic Deep Water and the resurgence of Antarctic Bottom Water. The study suggests that the mechanism behind this event is a significant part of the deglacial sequence.
Article
Geosciences, Multidisciplinary
Karen A. McKinnon, Isla R. Simpson
Summary: The study reveals that the 2021 heatwave in the Pacific Northwest was extremely rare, occurring with a frequency of approximately one in a hundred thousand years. Although historical data does not indicate a faster warming rate in the upper tail of temperature compared to the mean, future projections show a significant positive trend in the probability of the most extreme events for locations with similar climatological characteristics.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geography, Physical
Shuai Zhang, Tiegang Li, Zhoufei Yu, Fengming Chang, Sifan Gu, Zhifang Xiong, Heng Liu, Fang Qian, Junru Zhang, Xuhua Cheng, Baohua Li
Summary: In this study, the thermohaline and δ13C variations in the Pacific intermediate water over the past 28,000 years were reconstructed based on sediment core analysis. It was found that during Heinrich Stadial 1, the temperature of intermediate water rapidly increased by approximately 6 degrees C and was accompanied by changes in Southern Ocean surface water, exhibiting typical Antarctic characteristics. The climatic development in the Southern Hemisphere and the advection of the thermal anomaly into the tropical Pacific intermediate water through the Southern Ocean are believed to be closely linked.
PALAEOGEOGRAPHY PALAEOCLIMATOLOGY PALAEOECOLOGY
(2023)
Article
Multidisciplinary Sciences
Torben Struve, David J. Wilson, Sophia K. V. Hines, Jess F. Adkins, Tina van de Flierdt
Summary: The interoceanic exchange of water masses is modulated by flow through key oceanic choke points. This study uses neodymium isotope signatures to trace circulation changes south of Tasmania during the last glacial period. The results show the presence of a unique radiogenic and young water mass, possibly due to a more vigorous Pacific overturning circulation.
NATURE COMMUNICATIONS
(2022)
Article
Oceanography
Tomo Kitahashi, Himiko Watanabe, Ken Ikehara, Robert G. Jenkins, Shigeaki Kojima, Motohiro Shimanaga
JOURNAL OF OCEANOGRAPHY
(2016)
Article
Geosciences, Multidisciplinary
Kan-Hsi Hsiung, Toshiya Kanamatsu, Ken Ikehara, Kazuya Shiraishi, Chorn-Shern Horng, Kazuko Usami
GEO-MARINE LETTERS
(2017)
Article
Geosciences, Multidisciplinary
Akiko Omura, Ken Ikehara, Kohsaku Arai, Udrekh
GEO-MARINE LETTERS
(2017)
Article
Geochemistry & Geophysics
Toshiya Kanamatsu, Kazuko Usami, Cecilia M. G. McHugh, Ken Ikehara
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2017)
Article
Geography, Physical
Sunghan Kim, Boo-Keun Khim, Ken Ikehara, Takuya Itaki, Akihiko Shibahara, Masanobu Yamamoto
GLOBAL AND PLANETARY CHANGE
(2017)
Article
Geography, Physical
Hiroyuki Takata, Takuya Itaki, Ken Ikehara, Boo-Keun Khim
Article
Geosciences, Multidisciplinary
Kazuko Usami, Ken Ikehara, Robert G. Jenkins, Juichiro Ashi
Article
Oceanography
Michinobu Kuwae, Masanobu Yamamoto, Takuya Sagawa, Ken Ikehara, Tomohisa Irino, Keiji Takemura, Hidetaka Takeoka, Takashige Sugimoto
PROGRESS IN OCEANOGRAPHY
(2017)
Article
Geography, Physical
Yoshimi Kubota, Nozomi Suzuki, Katsunori Kimoto, Masao Uchida, Takuya Itaki, Ken Ikehara, Ryoung Ah Kim, Kyung Eun Lee
QUATERNARY INTERNATIONAL
(2017)
Article
Geography, Physical
Ken Ikehara, Kazuko Usami, Toshiya Kanamatsu, Tohru Danhara, Tohru Yamashita
QUATERNARY INTERNATIONAL
(2017)
Article
Environmental Sciences
Atsuyuki Ohta, Noboru Imai, Yoshiko Tachibana, Ken Ikehara
Article
Geography, Physical
Hiroyuki Takata, Naohisa Nishida, Ken Ikehara, Kota Katsuki, Boo-Keun Khim
QUATERNARY INTERNATIONAL
(2018)
Article
Geosciences, Multidisciplinary
Tomohisa Irino, Ryuji Tada, Ken Ikehara, Takuya Sagawa, Akinori Karasuda, Shunsuke Kurokawa, Arisa Seki, Song Lu
PROGRESS IN EARTH AND PLANETARY SCIENCE
(2018)
Article
Geosciences, Multidisciplinary
Ryuji Tada, Tomohisa Irino, Ken Ikehara, Akinori Karasuda, Saiko Sugisaki, Chuang Xuan, Takuya Sagawa, Takuya Itaki, Yoshimi Kubota, Song Lu, Arisa Seki, Richard W. Murray, Carlos Alvarez-Zarikian, William T. Anderson, Maria-Angela Bassetti, Bobbi J. Brace, Steven C. Clemens, Marcio H. da Costa Gurgel, Gerald R. Dickens, Ann G. Dunlea, Stephen J. Gallagher, Liviu Giosan, Andrew C. G. Henderson, Ann E. Holbourn, Christopher W. Kinsley, Gwang Soo Lee, Kyung Eun Lee, Johanna Lofi, Christina I. C. D. Lopes, Mariem Saavedra-Pellitero, Larry C. Peterson, Raj K. Singh, Samuel Toucanne, Shiming Wan, Hongbo Zheng, Martin Ziegler
PROGRESS IN EARTH AND PLANETARY SCIENCE
(2018)
Article
Geosciences, Multidisciplinary
Takuya Sagawa, Yoshitaka Nagahashi, Yasufumi Satoguchi, Ann Holbourn, Takuya Itaki, Stephen J. Gallagher, Mariem Saavedra-Pellitero, Ken Ikehara, Tomohisa Irino, Ryuji Tada
PROGRESS IN EARTH AND PLANETARY SCIENCE
(2018)