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Other research product . Collection . 2016

Uvigerina spp. δ¹⁸O and Mg/Ca measurements from sediment cores JR244-GC528 and MD07-3076, supplement to: Roberts, Jenny; Gottschalk, Julia; Skinner, Luke C; Peck, Victoria L; Kender, Sev; Elderfield, Henry; Waelbroeck, Claire; Vázquez Riveiros, Natalia; Hodell, David A (2016): Evolution of South Atlantic density and chemical stratification across the last deglaciation. Proceedings of the National Academy of Sciences, 113(3), 514-519

Roberts, Jenny; Gottschalk, Julia; Skinner, Luke C; Peck, Victoria L; Kender, Sev; Elderfield, Henry; Waelbroeck, Claire; +2 Authors
Open Access
English
Published: 01 Jan 2016
Publisher: PANGAEA - Data Publisher for Earth & Environmental Science
Abstract

Explanations of the glacial-interglacial variations in atmospheric pCO2 invoke a significant role for the deep ocean in the storage of CO2. Deep-ocean density stratification has been proposed as a mechanism to promote the storage of CO2 in the deep ocean during glacial times. A wealth of proxy data supports the presence of a "chemical divide" between intermediate and deep water in the glacial Atlantic Ocean, which indirectly points to an increase in deep-ocean density stratification. However, direct observational evidence of changes in the primary controls of ocean density stratification, i.e., temperature and salinity, remain scarce. Here, we use Mg/Ca-derived seawater temperature and salinity estimates determined from temperature-corrected d18O measurements on the benthic foraminifer Uvigerina spp. from deep and intermediate water-depth marine sediment cores to reconstruct the changes in density of sub-Antarctic South Atlantic water masses over the last deglaciation (i.e., 22-2 ka before present). We find that a major breakdown in the physical density stratification significantly lags the breakdown of the deep-intermediate chemical divide, as indicated by the chemical tracers of benthic foraminifer d13C and foraminifer/coral 14C. Our results indicate that chemical destratification likely resulted in the first rise in atmospheric pCO2, whereas the density destratification of the deep South Atlantic lags the second rise in atmospheric pCO2 during the late deglacial period. Our findings emphasize that the physical and chemical destratification of the ocean are not as tightly coupled as generally assumed.

Funded by
UKRI| The bi-polar seesaw and CO2: Is there anything special about 'Terminal seesaw events'?
Project
  • Funder: UK Research and Innovation (UKRI)
  • Project Code: NE/J010545/1
  • Funding stream: NERC
,
EC| NEWLOG
Project
NEWLOG
New Directions Linking Ocean Geochemistry, Biomineralization and Palaeoclimate
  • Funder: European Commission (EC)
  • Project Code: 267931
  • Funding stream: FP7 | SP2 | ERC
,
EC| ACCLIMATE
Project
ACCLIMATE
Elucidating the Causes and Effects of Atlantic Circulation Changes through Model-Data Integration
  • Funder: European Commission (EC)
  • Project Code: 339108
  • Funding stream: FP7 | SP2 | ERC
Related to Research communities
European Marine Science
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