Stable carbon and oxygen isotope ratios of planktonic foraminifera from the equatorial Atlantic, supplement to: McIntyre, Andrew; Ruddiman, William F; Karlin, K; Mix, Alan C (1989): Surface water response of the Equatorial Atlantic Ocean to orbital forcing. Paleoceanography, 4(1), 19-55

DOI

Carbon isotopic records of nutrient-depleted surface water place constraints on the past fertility of the oceans and on past atmospheric pCO2 levels. The best records of nutrient-depleted delta13C are obtained from planktonic foraminifera living in the thick mixed layers of the western equatorial and tropical Atlantic Ocean. We have produced a composite, stacked Globigerinoides sacculifer delta13C record from the equatorial Atlantic, which exhibits significant spectral power at the 100,000- and 41,000-year Milankovitch periods, but no power at the 23,000-year period. Similar to the record presented by Shackleton and Pisias [1985], surface-deep ocean Delta delta13C produced with the G. sacculifer record leads the delta18O ice volume record. However, the glacial-interglacial amplitudes of Delta delta13C differ between our record and Shackleton and Pisias [1985] record. Although large changes in Delta delta13C occur in the equatorial Atlantic during early stages of the last three glacial cycles, surface-deep Delta delta13C at glacial maxima (18O stage 2, late stage 6, and late stage 8) was only about 0.2‰ greater than during the subsequent interglacial. Our results imply that nutrient-driven pCO2 changes account for about one third of the pCO2 decrease observed in ice cores, and consequently, Delta delta13C should not be used as a proxy pCO2 index. Enough variance in the ice core pCO2 records remains to be explained that conclusions about pCO2 and ice volume phase relationships should also be reexamined. As much as 40 ppm pCO2 change still has not been accounted for by models of past physics and chemistry of the ocean.

Identifier
DOI https://doi.org/10.1594/PANGAEA.692012
Related Identifier https://doi.org/10.1029/PA004i001p00019
Related Identifier https://doi.org/10.1029/PA002i005p00489
Related Identifier https://doi.org/10.1007/978-94-009-2446-8_7
Metadata Access https://ws.pangaea.de/oai/provider?verb=GetRecord&metadataPrefix=datacite4&identifier=oai:pangaea.de:doi:10.1594/PANGAEA.692012
Provenance
Creator Curry, William B; Crowley, Thomas J
Publisher PANGAEA - Data Publisher for Earth & Environmental Science
Publication Year 1987
Rights Creative Commons Attribution 3.0 Unported
OpenAccess true
Representation
Language English
Resource Type Supplementary Collection of Datasets
Format application/zip
Size 10 datasets
Discipline Earth System Research
Spatial Coverage (-79.378W, 4.337S, -19.852E, 26.400N); Caribbean Sea/RIDGE; Atlantic Ocean
Temporal Coverage Begin 1968-01-21T00:00:00Z
Temporal Coverage End 1984-11-08T00:00:00Z