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dc.contributor.authorBradtmiller, Louisa I.  Concept link
dc.contributor.authorAnderson, Robert F.  Concept link
dc.contributor.authorFleisher, Martin Q.  Concept link
dc.contributor.authorBurckle, Lloyd H.  Concept link
dc.date.accessioned2010-05-18T14:18:57Z
dc.date.available2010-05-18T14:18:57Z
dc.date.issued2009-06-03
dc.identifier.citationPaleoceanography 24 (2009): PA2214en_US
dc.identifier.urihttps://hdl.handle.net/1912/3460
dc.descriptionAuthor Posting. © American Geophysical Union, 2009. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Paleoceanography 24 (2009): PA2214, doi:10.1029/2008PA001693.en_US
dc.description.abstractThe silicic acid leakage hypothesis (SALH) predicts that during glacial periods excess silicic acid was transported from the Southern Ocean to lower latitudes, which favored diatom production over coccolithophorid production and caused a drawdown of atmospheric CO2. Downcore records of 230Th-normalized opal (biogenic silica) fluxes from 31 cores in the Pacific sector of the Southern Ocean were used to compare diatom productivity during the last glacial period to that of the Holocene and to examine the evidence for increased glacial Si export to the tropics. Average glacial opal fluxes south of the modern Antarctic Polar Front (APF) were less than during the Holocene, while average glacial opal fluxes north of the APF were greater than during the Holocene. However, the magnitude of the increase north of the APF was not enough to offset decreased fluxes to the south, resulting in a decrease in opal burial in the Pacific sector of the Southern Ocean during the last glacial period, equivalent to approximately 15 Gt opal ka−1. This is consistent with the work of Chase et al. (2003a), and satisfies the primary requirement of the SALH, assuming that the upwelled supply of Si was approximately equivalent during the Holocene and the glacial period. However, previous results from the equatorial oceans are inconsistent with the other predictions of the SALH, namely that either the Corg:CaCO3 ratio or the rate of opal burial should have increased during glacial periods. We compare the magnitudes of changes in the Southern Ocean and the tropics and suggest that Si escaping the glacial Southern Ocean must have had an alternate destination, possibly the continental margins. There is currently insufficient data to test this hypothesis, but the existence of this sink and its potential impact on glacial pCO2 remain interesting topics for future study.en_US
dc.description.sponsorshipFunding for this research was provided in part by the U.S. NSF (grant OPP02-30268). We thank the core repository at LDEO and the Antarctic Research Facility at FSU for providing samples.en_US
dc.format.mimetypeapplication/pdf
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dc.language.isoen_USen_US
dc.publisherAmerican Geophysical Unionen_US
dc.relation.urihttps://doi.org/10.1029/2008PA001693
dc.subjectSouthern Oceanen_US
dc.subjectSilica cyclesen_US
dc.subjectPaleoceanographyen_US
dc.titleComparing glacial and Holocene opal fluxes in the Pacific sector of the Southern Oceanen_US
dc.typeArticleen_US
dc.identifier.doi10.1029/2008PA001693


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