Correlation of Asian dust, paleoproductivity in North Pacific and CO₂ in the atmosphere during the past 25000 years

About 700 samples of loess and paleosol were collected from Lingtai (35°04' N, 107°39' E) loess profile of Chinese Loess Plateau, the fluxes of dust and the elements Fe, Si and P contained were reestablished by the method of Al fluxes. The results demonstrated that the fluxes of dust and the three elements fluctuated at glacial and interglacial scale during the past 250 ka. They increased significantly during glacial stages, such as OIS (Oxygen Isotope Stage) 2, 4 and 6, but decreased obviously during interglacial stages (OIS 5 and OIS 7), which are corresponding to the changes of paleoproductivity of North Pacific and CO₂ in atmosphere. Studies have demonstrated that iron from dust over open sea can simulate the productivity of phytoplankton, and then increase the absorption of CO₂ by sea. The correlations of changes of dust and elements fluxes in Lingtai loess profile, paleoproductivity in North Pacific and CO₂ in the atmosphere during the past 250 ka demonstrate that dust from Asia could improve the productivity of North Pacific through its biogeochemical cycle and lower CO₂ in the atmosphere. Based on the comparison of global dust record and CO₂ changes during the last glaciation maximum (LGM), the contribution of Asian dust to global CO₂ change was preliminary estimated as 4 × l0^-6~9 × l0^-6, which is roughly a fourth of the global change in CO₂ caused by dust deposition.