Silicic productivity record in the Westen Pacific Warm Pool in the last 700 ka and its climatic effect

The Quaternary silicic productivity levels in the Western Pacific Warm Pool (WPWP) are believed to play a crucial role in regulating changes in global atmospheric CO₂ partial pressure. However, there is a debate regarding the factors that control the productivity levels. We examined the biogenic opal of core MD06-3047, which is located in the central region of the WPWP, to investigate the controlling factors and climatic effects on silicic productivity over the past 700 kyr. Our findings indicate that the variation in silicic productivity in the WPWP exhibits significant glacial-interglacial cycles: higher levels during glacial periods while lower levels during interglacial periods. The primary controlling factors might be sediment erosion and weathering on the East Luzon continental shelf, the aeolian dust input, as well as the depth of the thermocline (DOT). The silicic acid leakage from the Southern Ocean may not have a significant impact. During glacial periods, physical erosion and silicate weathering of exposed continental shelf sediments near tropical volcanic arcs were intensified, and so did the dust input, which resulted in increased input of silicate and iron to the WPWP. The shallower DOT during glacial periods led to a smaller nutrient vertical space and increased retention time, thereby increasing the glacial productivity of the WPWP, and potentially reducing the partial pressure of atmospheric CO₂.