Holocene paleoenvironment changes in the northern Yellow Sea: Evidence from alkenone-derived sea surface temperature

Abstract

A well-dated, high-resolution sea surface temperature (SST) record based on long chain unsaturated alkenones from a northern Yellow Sea (NYS) sediment core is present in this study. Variations in linear sedimentation rate, alkenone content and SST clearly reveal five distinct stages, consistent with changes in local sea level as well as the evolution of the Yellow Sea Warm Current (YSWC). Before 8.9cal.kyr BP, the marine transgression might not reach to the northern part of the NYS. A shallow coastal environment was formed from 8.9 to 8.5cal.kyr BP, with a subsequent fast transgression during 7.8 to 6.5cal.kyr BP. After 5.8cal.kyr BP, the NYS was dominated by a relatively constant marine environment. SST records reveal that the YSWC was likely to have started since 7.0cal.kyr and strengthened progressively in period of 7.0–5.5cal.kyr BP. After 5.5cal.kyr BP, the SST elevated about 1.5°C, which correlated well to salinity changes along the YSWC indicating that the formation time of the modern YSWC was at about 5.5cal.kyr BP. The SST variation shows a millennial period of ~1500-yr and centennial periods of 131-yr and 113-yr. The ~1.5kyr cycle dominated the period of 8.9–5.5cal.kyr BP, suggesting a tele-connection between the Yellow Sea SST and global climate changes, might through the Kuroshio current. Centennial periods dominated almost all of cold periods recorded in core BY14, implying the signature of solar irradiance cycles by means of the strengthened East Asia Winter Monsoon (EAWM).