Iron in the NEEM ice core relative to Asian loess records over the last glacial-interglacial cycle

Xiao Cunde |National Science Review

Iron in the NEEM ice core relative to Asian loess records over the last glacial-interglacial cycle

Xiao Cunde,Du Zhiheng,Handley Mike J.,Mayewski Paul A.,Cao Junji,Schuepbach Simon,Zhang Tong,Petit Jean-Robert,Li Chuanjin,Han Yeongcheol,Li Yuefang,Ren Jiawen

National Science Review

Published JUL 2021

DOI: 10.1093/nsr/nwaa144

Abstract

Mineral dust can indirectly affect the climate by supplying bioavailable iron (Fe) to the ocean. Here, we present the records of dissolved Fe (DFe) and total Fe (TDFe) in North Greenland Eemian Ice Drilling (NEEM) ice core over the past 110 kyr BP. The Fe records are significantly negatively correlated with the carbon-dioxide (CO2) concentrations during cold periods. The results suggest that the changes in Fe fluxes over the past 110 kyr BP in the NEEM ice core are consistent with those in Chinese loess records because the mineral-dust distribution is controlled by the East Asian deserts. Furthermore, the variations in the dust input on a global scale are most likely driven by changes in solar radiation during the last glacial-interglacial cycle in response to Earth's orbital cycles. In the last glacial-interglacial cycle, the DFe/TDFe ratios were higher during the warm periods (following the post-Industrial Revolution and during the Holocene and last interglacial period) than during the main cold period (i.e. the last glacial maximum (LGM)), indicating that the aeolian input of iron and the iron fertilization effect on the oceans have a non-linear relationship during different periods. Although the burning of biomass aerosols has released large amounts of DFe since the Industrial Revolution, no significant responses are observed in the DFe and TDFe variations during this period, indicating that severe anthropogenic contamination has no significant effect on the DFe (TDFe) release in the NEEM ice core.