TY - JOUR
T1 - Paleoceanographic evolution of the Japan Sea over the last 460 kyr – A coccolithophore perspective
AU - Saavedra-Pellitero, Mariem
AU - Baumann, Karl Heinz
AU - Gallagher, Stephen John
AU - Sagawa, Takuya
AU - Tada, Ryuji
N1 - Funding Information:
We would like to thank Rick Murray, Carlos Álvarez Zarikian, Bobbi Brace and the 346 Expedition Scientists as well as technicians and crew on board Joides Resolution for the mudline and sediment samples retrieved during IODP Expedition 346. The KR15-10 science party and crew are also thanked for providing the surface sediment samples collected during this JAMSTEC Expedition onboard R/V Kairei. Laboratory assistance from Nele Vollmar is greatly appreciated. Thoughtful comments from four reviewers and the Editor-in-Chief, Rick Jordan, greatly improved this manuscript during the review process. We acknowledge IODP, ECORD and BGR for choosing to support Mariem Saavedra-Pellitero as a shipboard scientist during IODP Exp. 346. Funding was provided by the Australian and New Zealand IODP Consortium (ANZIC) and the Australian research Council (ARC) Basins Genesis Hub ( IH130200012 ) to Stephen J. Gallagher. This study was also supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI ( 15H02143 ). Data are available in Pangaea database ( https://doi.pangaea.de/10.1594/PANGAEA.892989 ).
Funding Information:
We would like to thank Rick Murray, Carlos Álvarez Zarikian, Bobbi Brace and the 346 Expedition Scientists as well as technicians and crew on board Joides Resolution for the mudline and sediment samples retrieved during IODP Expedition 346. The KR15-10 science party and crew are also thanked for providing the surface sediment samples collected during this JAMSTEC Expedition onboard R/V Kairei. Laboratory assistance from Nele Vollmar is greatly appreciated. Thoughtful comments from four reviewers and the Editor-in-Chief, Rick Jordan, greatly improved this manuscript during the review process. We acknowledge IODP, ECORD and BGR for choosing to support Mariem Saavedra-Pellitero as a shipboard scientist during IODP Exp. 346. Funding was provided by the Australian and New Zealand IODP Consortium (ANZIC) and the Australian research Council (ARC) Basins Genesis Hub (IH130200012) to Stephen J. Gallagher. This study was also supported by the Japan Society for the Promotion of Science (JSPS) KAKENHI (15H02143). Data are available in Pangaea database (https://doi.pangaea.de/10.1594/PANGAEA.892989).
Publisher Copyright:
© 2019 Elsevier B.V.
PY - 2019/9/1
Y1 - 2019/9/1
N2 - Changes in the intensity of the influx of the Tsushima Warm Current (TWC) in the south-central part of the Japan Sea (JS), or East Sea in Korean, were reconstructed for the last 460 kyr at IODP Site U1427 using the composition and abundance of the coccolithophore assemblage. In addition, the recent distribution of coccolithophore taxa in the JS and the East China Sea was assessed using electron microscopy. Coccolithophore assemblages, dominated by Emiliania huxleyi and Gephyrocapsa species, and coccolith abundance reveal a strong relationship between sea level and ocean variability over the last five glacial/interglacial cycles, in good agreement with planktic foraminiferal data. Three different circulation modes based on calcareous nannofossil and foraminifera TWC indicators were proposed for the JS. Coccolith production was low and TWC indicators (i.e., Gephyrocapsa oceanica, Calcidiscus leptoporus s.l., and Helicosphaera carteri) absent due to the isolation of the JS during glacials in response to global sea level falls (Mode 1). In contrast, coccolith abundance and TWC indicators reach a maximum due to the most intense TWC flow through the Tsushima Strait during interglacials (Mode 3). Intermediate conditions (Mode 2) are characterized by moderate/high coccolith numbers, presence of TWC coccolith indicators, and rare TWC planktic foraminifera indicators. This mode resulted in intermittent variations in the contribution of the TWC and East China Sea coastal water due to relatively low sea level stands (ca. −90 m to −20 m). Coccoliths dominated the carbonate sequence prior to MIS 8 and were major contributors to the total carbonate of the sediment at Site U1427, suggesting high coccolithophore productivity and a bloom-type environment during MIS 11 and 9. These changes in the carbonate chemistry caused by glacio-eustacy in the JS at the northwest margin of the Pacific Ocean should be considered in future paleoceanographic and paleoclimate models.
AB - Changes in the intensity of the influx of the Tsushima Warm Current (TWC) in the south-central part of the Japan Sea (JS), or East Sea in Korean, were reconstructed for the last 460 kyr at IODP Site U1427 using the composition and abundance of the coccolithophore assemblage. In addition, the recent distribution of coccolithophore taxa in the JS and the East China Sea was assessed using electron microscopy. Coccolithophore assemblages, dominated by Emiliania huxleyi and Gephyrocapsa species, and coccolith abundance reveal a strong relationship between sea level and ocean variability over the last five glacial/interglacial cycles, in good agreement with planktic foraminiferal data. Three different circulation modes based on calcareous nannofossil and foraminifera TWC indicators were proposed for the JS. Coccolith production was low and TWC indicators (i.e., Gephyrocapsa oceanica, Calcidiscus leptoporus s.l., and Helicosphaera carteri) absent due to the isolation of the JS during glacials in response to global sea level falls (Mode 1). In contrast, coccolith abundance and TWC indicators reach a maximum due to the most intense TWC flow through the Tsushima Strait during interglacials (Mode 3). Intermediate conditions (Mode 2) are characterized by moderate/high coccolith numbers, presence of TWC coccolith indicators, and rare TWC planktic foraminifera indicators. This mode resulted in intermittent variations in the contribution of the TWC and East China Sea coastal water due to relatively low sea level stands (ca. −90 m to −20 m). Coccoliths dominated the carbonate sequence prior to MIS 8 and were major contributors to the total carbonate of the sediment at Site U1427, suggesting high coccolithophore productivity and a bloom-type environment during MIS 11 and 9. These changes in the carbonate chemistry caused by glacio-eustacy in the JS at the northwest margin of the Pacific Ocean should be considered in future paleoceanographic and paleoclimate models.
KW - Assemblage
KW - Biogeography
KW - Coccolith
KW - Coccolithophores
KW - East China Sea
KW - Japan Sea
KW - Tsushima current
UR - http://www.scopus.com/inward/record.url?scp=85061427589&partnerID=8YFLogxK
U2 - 10.1016/j.marmicro.2019.01.001
DO - 10.1016/j.marmicro.2019.01.001
M3 - Article
AN - SCOPUS:85061427589
SN - 0377-8398
VL - 152
JO - Marine Micropaleontology
JF - Marine Micropaleontology
M1 - 101720
ER -