Data/hora: 07/06/2024 00:28:12

Provedor de dados: | 5
País: | France
Título: | Evolution of South Atlantic density and chemical stratification across the last deglaciation
Autores: | Roberts, Jenny; Gottschalk, Julia; Skinner, Luke C.; Peck, Victoria L.; Kender, Sev; Elderfield, Henry; Waelbroeck, Claire; Riveiros, Natalia Vazquez; Hodell, David A.
Data: | 2016-01
Ano: | 2016
Palavras-chave: | South Atlantic; Density gradient; Ocean stratification; Last deglaciation; Atmospheric CO2.
Resumo: | Explanations of the glacial-interglacial variations in atmospheric pCO(2) 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 delta O-18 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 delta C-13 and foraminifer/coral C-14. Our results indicate that chemical destratification likely resulted in the first rise in atmospheric pCO(2), whereas the density destratification of the deep South Atlantic lags the second rise in atmospheric pCO(2) 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.
Tipo: | Text
Idioma: | Inglês

Identificador:

https://archimer.ifremer.fr/doc/00421/53276/54569.pdf

https://archimer.ifremer.fr/doc/00421/53276/54570.pdf

DOI:10.1073/pnas.1511252113

https://archimer.ifremer.fr/doc/00421/53276/

Editor: | Natl Acad Sciences
Formato: | application/pdf
Fonte: | Proceedings Of The National Academy Of Sciences Of The United States Of America (0027-8424) (Natl Acad Sciences), 2016-01 , Vol. 113 , N. 3 , P. 514-519

Fonte:

2018 National Academy of Sciences

info:eu-repo/semantics/openAccess

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