Publication Date:
2022-05-25
Description:
Author Posting. © American Geophysical Union, 2004. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 19 (2004): PA2018, doi:10.1029/2003PA000986.
Description:
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 ex230Th-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.
Description:
This research was partly supported
by NSF grant OCE-0095617 and funds from the Northern Illinois University
Graduate School (Loubere); the NASA Michigan Space Grant Consortium
Seed Grant for summer, 2001 for 230Th analyses at WHOI (Mekik);
the French Ministere de l’Education Nationale, de la Recherche et de la
Technologie, and a EURODOC grant from the Region Rhone-Alpes
(Pichat).
Keywords:
Calcite fluxes
;
Eastern equatorial Pacific
;
Glacial-interglacial
Repository Name:
Woods Hole Open Access Server
Type:
Article
Format:
application/pdf
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