Fig. 1

Map of sample locations. Locations for surface seawater samples (red circles) and surface–subsurface seawater samples (red squares) are shown together with the present current system (Ichikawa and Beardsley 2002). Surface sediments were taken from HR11, MT5, HR9, HR6, HR2, and St.1. Locations for sediment core at KY, A7, 403, and 404 (Sun et al. 2005; Lin et al. 2006; Chen et al. 2010; Kubota et al. 2010) are also shown. CDW and YSCCW represent the Changjiang diluted water and Yellow Sea Central Cold Water, respectively. The bathymetric contours represent 100, 200, 300, 1000, 2000, and 3000 m