Export fluxes of calcite in the eastern equatorial Pacific from the Last Glacial Maximum to present

• Published in: Paleoceanography
• Main Authors: Loubere, Paul, Mekik, Figen, Francois, Roger, Pichat, Sylvain
• Other Authors: Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2004
• Subjects: calcite fluxes; eastern equatorial Pacific; glacial-interglacial; [SDU.OCEAN]Sciences of the Universe [physics]/Ocean; Atmosphere; [SDU.STU.CL]Sciences of the Universe [physics]/Earth Sciences/Climatology; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; [SDU.STU.PG]Sciences of the Universe [physics]/Earth Sciences/Paleontology; Pacific; Southern Ocean
• Online Access: https://hal.science/hal-02884308; https://hal.science/hal-02884308/document; https://hal.science/hal-02884308/file/2003PA000986.pdf; https://doi.org/10.1029/2003PA000986

International audience The eastern equatorial Pacific (EEP) is an important center of biological productivity, generating significant organic carbon and calcite fluxes to the deep ocean. We reconstructed paleocalcite flux for the past 30,000 years in four cores collected beneath the equatorial upwelling and the South Equatorial Current (SEC) by measuring ex 230 Th-normalized calcite accumulation rates corrected for dissolution with a newly developed proxy for ''fraction of calcite preserved.'' This method produced very similar results at the four sites and revealed that the export flux of calcite was 30-50% lower during the LGM compared to the Holocene. The internal consistency of these results supports our interpretation, which is also in agreement with emerging data indicating lower glacial productivity in the EEP, possibly as a result of lower nutrient supply from the southern ocean via the Equatorial Undercurrent. However, these findings contradict previous interpretations based on mass accumulation rates (MAR) of biogenic material in the sediment of the EEP, which have been taken as reflecting higher glacial productivity due to stronger wind-driven upwelling.