Journal cover Journal topic
Climate of the Past An interactive open-access journal of the European Geosciences Union
doi:10.5194/cp-2017-58
© Author(s) 2017. This work is distributed
under the Creative Commons Attribution 3.0 License.
Research article
24 Apr 2017
Review status
This discussion paper is under review for the journal Climate of the Past (CP).
Holocene dynamics in the Bering Strait inflow to the Arctic and the Beaufort Gyre circulation based on sedimentary records from the Chukchi Sea
Masanobu Yamamoto1,2,3, Seung-Il Nam4, Leonid Polyak5, Daisuke Kobayashi3, Kenta Suzuki3, Tomohisa Irino1,3, and Koji Shimada6 1Faculty of Environmental Earth Science, Hokkaido University, Kita-10, Nishi-5, Kita-ku, Sapporo 060-0810 Japan
2Global Institution for Collaborative Research and Education, Hokkaido University, Kita-10, Nishi-5, Kita-ku, Sapporo 060-0810 Japan
3Gradute School of Environmental Science, Hokkaido University, Kita-10, Nishi-5, Kita-ku, Sapporo 060-0810 Japan
4Korea Polar Research Institute, 26 Songdomirae-ro, Yeonsu-gu, Incheon 21990, Republic of Korea
5Byrd Polar and Climate Research Center, The Ohio State University, Columbus, OH 43210 USA
6Tokyo University of Marine Science and Technology, 4-5-7, Konan, Minato-ku, Tokyo 108-8477, Japan
Abstract. The Beaufort Gyre (BG) and the Bering Strait inflow (BSI) are important elements of the Arctic Ocean circulation system and major controls on the distribution of Arctic sea ice. We report records of the quartz/feldspar and chlorite/illite ratios in three sediment cores from the northern Chukchi Sea providing insights into the long-term dynamics of the BG circulation and the BSI during the Holocene. The quartz/feldspar ratio, a proxy of the BG strength, gradually decreased during the Holocene, suggesting a long-term decline in the BG strength, consistent with orbitally-controlled decrease in summer insolation. We suppose that the BG rotation weakened as a result of increasing stability of sea-ice cover at the margins of the Canada Basin, driven by decreasing insolation. Millennial to multi-centennial variability in the quartz/feldspar ratio (the BG circulation) is consistent with fluctuations in solar irradiance, suggesting that solar activity affected the BG strength on these timescales. The BSI approximated by the chlorite/illite record shows intensified flow from the Bering Sea to the Arctic during the middle Holocene, which is attributed primarily to the effect of an overall weaker Aleutian Low. The middle Holocene intensification of the BSI was associated with decrease in sea ice concentrations and increase in marine production, as indicated by biomarker concentrations, suggesting an influence of the BSI on sea ice distribution and biological production in the Chukchi Sea.

Citation: Yamamoto, M., Nam, S.-I., Polyak, L., Kobayashi, D., Suzuki, K., Irino, T., and Shimada, K.: Holocene dynamics in the Bering Strait inflow to the Arctic and the Beaufort Gyre circulation based on sedimentary records from the Chukchi Sea, Clim. Past Discuss., doi:10.5194/cp-2017-58, in review, 2017.
Masanobu Yamamoto et al.
Masanobu Yamamoto et al.
Masanobu Yamamoto et al.

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Short summary
Based on mineral records from the northern Chukchi Sea, we report a long-term decline in the Beaufort Gyre (BG) strength during the Holocene, consistent with decrease in summer insolation. Multi-centennial variability in the BG circulation is consistent with fluctuations in solar irradiance. The Bering Strait inflow shows intensification during the middle Holocene, associated with sea ice retreat and increase of marine production in the Chukchi Sea, which is attributed to a weaker Aleutian Low.
Based on mineral records from the northern Chukchi Sea, we report a long-term decline in the...
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