Tracking via Coccolith Assemblages the East Asian Monsoon and Carbonate Production in the South China Sea During Termination II and Marine Isotope Stage 5e

Abstract Coccolith assemblages from the last 158 kyr, encompassing Marine Isotope Stage (MIS) 5e (130–116 kyr) and preceding deglaciation (Termination II; T‐II), offer important insights about current and future climate changes. The South China Sea (SCS) represents a perfect area for reconstructing past East Asian Monsoon (EAM) dynamics thanks to its semi‐enclosed location and high sensitivity to climate variability. Here, we investigated the coccolith assemblages at Site U1501 (northern SCS) deposited during MIS 6‐3 (158–50 kyr). Coccolith abundances, community composition, and calcium carbonate (CaCO 3 ) production/accumulation were used to reconstruct past climate, EAM variations, and oceanographic conditions in SCS. Coccolith assemblages record a persistent oligotrophic regime with a shallow nutri‐thermocline. Coccolith abundance variations align with changes in monsoon dynamics, showing that EAM strengthened during MIS 6, T‐II, cold substages of MIS 5, and MIS 4/3 transition, and weakened during interglacials. The distinction adopted here for the first time between lightly and heavily calcified species revealed that the latter contributed significantly to CaCO 3 production during T‐II and MIS 5e despite their general lower abundances. Comparison between MIS 5e and future predicted scenarios for the SCS shows a strong similarity in the evolution of EAM dynamics. The weakening of Winter EAM recorded for the past interglacial is also predicted for 2100. This suggests a possible similar coccolithophores' response to future climate conditions in the SCS, with an increase in their abundance and calcite production/accumulation. These findings confirm the potential of coccolithophores in climate reconstructions, opening interesting perspectives on their fate in future oceans.