EGU2020-12967, updated on 12 Jun 2020
https://doi.org/10.5194/egusphere-egu2020-12967
EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Evolution of upper water column structure inferred from paired alkenone and tetraether lipid proxies in the central Japan/East Sea since 25 ka BP

Yonghua Wu1,2, Xuefa Shi1,2, Jianjun Zou1,2, Xun Gong3, Yanguang Liu1,2, Gerrit Lohmann3, Lester Lembke-Jene3, and Sergey Gorbarenko4
Yonghua Wu et al.
  • 1Key Laboratory of Marine Sedimentology and Environmental Geology, First Institute of Oceanography, MNR, Qingdao 266061, China
  • 2Laboratory for Marine Geology, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266061, China
  • 3Alfred-Wegener-Institut Helmholtz-Zentrum für Polar- und Meeresforschung, Bussestr. 24, 27570 Bremerhaven, Germany
  • 4V.I. Il'ichev Pacific Oceanological Institute, Far East Branch of Russian Academy of Science, (FEB of RAS), Vladivostok 690041, Russia

We measure and analyse the alkenone and tetraether lipid records over the past 25 ka, from a sediment core recovered from the central Japan/East Sea. In our results, UK′37- and TEX86- derived temperatures commonly represent warm signals during the period of 25-16.2 ka BP, indicating fresher and thus a stratified surface ocean. In comparison, the UK′37- and TEX86- derived temperatures become diverged abruptly after 16.2 ka BP, suggesting a thermal gradient between surface and subsurface water. In addition, the isoprenoidal glycerol dialkyl glycerol tetraethers (GDGT) community structure index, GDGT-[2]/[3] ratio is high during the period of 25-16.2 ka BP and drops sharply along with the TEX86- derived temperatures at 16.2 ka BP, which is likely attributed to changes in the depth of GDGT export and/or in archaeal community structure. Specifically, the high GDGT-[2]/[3] ratio (larger than 8) can be related to strongly stratified surface Japan/East Sea. Moreover, the UK′37- and TEX86- derived temperatures start converging at 5.8 ka BP, representing the impact of the Tsushima Warm Current until nowadays. Note: This study was supported by the National Natural Science Foundation of China (Grants No. 41420104005, U1606401) and National Program on Global Change and Air-Sea Interaction (GASI-GEOGE-03 &-04).

How to cite: Wu, Y., Shi, X., Zou, J., Gong, X., Liu, Y., Lohmann, G., Lembke-Jene, L., and Gorbarenko, S.: Evolution of upper water column structure inferred from paired alkenone and tetraether lipid proxies in the central Japan/East Sea since 25 ka BP, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12967, https://doi.org/10.5194/egusphere-egu2020-12967, 2020