TY - JOUR
T1 - A 150-year variation of the Kuroshio transport inferred from coral nitrogen isotope signature
AU - Yamazaki, Atsuko
AU - Watanabe, Tsuyoshi
AU - Tsunogai, Urumu
AU - Iwase, Fumihito
AU - Yamano, Hiroya
N1 - Funding Information:
We thank H. Adachi, M. Ikeda, K. Hyeong, M. Shimamura, T. Yamazaki, K. Nishimoto, S. Nakachi, J. Isasa, and the Tatsukushi Diving Center for their cooperation in the field works. K. Sugihara identified the species of coral specimens. R. Nakaya helped in the subsampling of coral cores. T. Irino supported the oxygen isotope analysis. T. Ohyama performed the water sample analysis. Geological Survey of Hokkaido and T. Nakamura supported the salinity measurements of seawater. The fieldwork was conducted through the financial support of the Environment Research and Technology Development Fund, Ministry of the Environment, Japan (RF-082) and Kuroshio Biological Research Foundation. A. Yamazaki was supported by Grants-in-Aid for JSPS research fellows. d15Ncoral data used in this study are available in Data S1 in the supporting information.
Publisher Copyright:
© 2016. American Geophysical Union. All Rights Reserved.
PY - 2016/6/1
Y1 - 2016/6/1
N2 - The Kuroshio Current is a major global ocean current that drives the physical ocean-atmosphere system with heat transport from tropical to temperate zones in the North Pacific Ocean. We reconstructed the variability of the Kuroshio transport over the past 150 years using coral skeletal nitrogen isotopic composition (δ15Ncoral). A 150 year δ15Ncoral record (1859–2008 A.D.) is 4 times the length of the observational record (1971 to present) and could provide a direct comparison with global climate change, such as the Pacific Decadal Oscillation (PDO) index and El-Niño–Southern Oscillation (ENSO), through recent global warming. Coral cores from Porites were collected from Tatsukushi Bay in 2008 on the Pacific coast of Japan, which is located on the northern front of the Kuroshio Current. δ15Ncoral was used as a proxy to record the δ15N of nitrate (δ15Nnitrate) controlled by the upwelling of subtropical subsurface water (δ15Nnitrate; ~ +2 − +3‰), and δ15Ncoral was negatively correlated with observations of the Kuroshio transport (R = −0.69, P < 0.001) and the 2 year lagged PDO index (R = −0.63, P < 0.005) from 1972 to 2007. The 150 year record of δ15Ncoral suggested that the Kuroshio transport varied with ~25 year cycle, and the amplitude became more stable, and the volume was intensified through the twentieth century. The Kuroshio transport was intensified by the La Niña state in the early 1900s and by the El Niño-PDO state after the 1920s. Our results suggested that the Kuroshio transport was influenced by the combined climate modes of ENSO and PDO during the last century.
AB - The Kuroshio Current is a major global ocean current that drives the physical ocean-atmosphere system with heat transport from tropical to temperate zones in the North Pacific Ocean. We reconstructed the variability of the Kuroshio transport over the past 150 years using coral skeletal nitrogen isotopic composition (δ15Ncoral). A 150 year δ15Ncoral record (1859–2008 A.D.) is 4 times the length of the observational record (1971 to present) and could provide a direct comparison with global climate change, such as the Pacific Decadal Oscillation (PDO) index and El-Niño–Southern Oscillation (ENSO), through recent global warming. Coral cores from Porites were collected from Tatsukushi Bay in 2008 on the Pacific coast of Japan, which is located on the northern front of the Kuroshio Current. δ15Ncoral was used as a proxy to record the δ15N of nitrate (δ15Nnitrate) controlled by the upwelling of subtropical subsurface water (δ15Nnitrate; ~ +2 − +3‰), and δ15Ncoral was negatively correlated with observations of the Kuroshio transport (R = −0.69, P < 0.001) and the 2 year lagged PDO index (R = −0.63, P < 0.005) from 1972 to 2007. The 150 year record of δ15Ncoral suggested that the Kuroshio transport varied with ~25 year cycle, and the amplitude became more stable, and the volume was intensified through the twentieth century. The Kuroshio transport was intensified by the La Niña state in the early 1900s and by the El Niño-PDO state after the 1920s. Our results suggested that the Kuroshio transport was influenced by the combined climate modes of ENSO and PDO during the last century.
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U2 - 10.1002/2015PA002880
DO - 10.1002/2015PA002880
M3 - Article
AN - SCOPUS:84978076928
VL - 31
SP - 838
EP - 846
JO - Paleoceanography and Paleoclimatology
JF - Paleoceanography and Paleoclimatology
SN - 2572-4517
IS - 6
ER -