Export fluxes of calcite in the eastern equatorial Pacific from the Last Glacial Maximum to present
MetadataShow full item record
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.
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.
Showing items related by title, author, creator and subject.
Lower export production during glacial periods in the equatorial Pacific derived from (231Pa/230Th)xs,0 measurements in deep-sea sediments Pichat, Sylvain; Sims, Kenneth W. W.; Francois, Roger; McManus, Jerry F.; Leger, Susan Brown; Albarede, Francis (American Geophysical Union, 2004-12-16)The (231Pa/230Th)xs,0 records obtained from two cores from the western (MD97-2138; 1°25′S, 146°24′E, 1900 m) and eastern (Ocean Drilling Program Leg 138 Site 849, 0°11.59′N, 110°31.18′W, 3851 m) equatorial Pacific display ...
Radiocarbon evidence for a possible abyssal front near 3.1 km in the glacial equatorial Pacific Ocean Keigwin, Lloyd D.; Lehman, Scott J. (2014-09)We investigate the radiocarbon ventilation age in deep equatorial Pacific sediment cores using the difference in conventional 14C age between coexisting benthic and planktonic foraminifera, and integrate those results with ...
Strong sea surface cooling in the eastern equatorial Pacific and implications for Galápagos Penguin conservation Karnauskas, Kristopher B.; Jenouvrier, Stephanie; Brown, Christopher W.; Murtugudde, Raghu (John Wiley & Sons, 2015-08-06)The Galápagos is a flourishing yet fragile ecosystem whose health is particularly sensitive to regional and global climate variations. The distribution of several species, including the Galápagos Penguin, is intimately ...