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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Variability in mid-depth ventilation of the western Atlantic Ocean during the last deglaciation

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Voigt, I. [1] ; Cruz, A. P. S. [2] ; Mulitza, S. [1] ; Chiessi, C. M. [3] ; Mackensen, A. [4] ; Lippold, J. [5] ; Antz, B. [6] ; Zabel, M. [1] ; Zhang, Y. [1] ; Barbosa, C. F. [2] ; Tisserand, A. A. [7]
Total Authors: 11
[1] Univ Bremen, MARUM Ctr Marine Environm Sci, Bremen - Germany
[2] Univ Fed Fluminense, Programa Posgrad Geoquim, Outeiro Sao Joao Batista S-No, Niteroi, RJ - Brazil
[3] Univ Sao Paulo, Sch Arts Sci & Humanities, Sao Paulo - Brazil
[4] Alfred Wegener Inst, Bremerhaven - Germany
[5] Heidelberg Univ, Inst Earth Sci, Heidelberg - Germany
[6] Heidelberg Univ, Inst Environm Phys, Heidelberg - Germany
[7] Bjerknes Ctr Climate Res, Uni Res Climate, Bergen - Norway
Total Affiliations: 7
Document type: Journal article
Source: PALEOCEANOGRAPHY; v. 32, n. 9, p. 948-965, SEP 2017.
Web of Science Citations: 10

Negative stable carbon isotopic excursions have been observed throughout most of the mid-depth (similar to 1000-3000m) Atlantic Ocean during Heinrich Stadial 1 (HS1) and the Younger Dryas (YD). Although there is an agreement that these mid-depth excursions were in some way associated with a slowdown of the Atlantic Meridional Overturning Circulation (AMOC), there is still no consensus on the precise mechanism(s). Here we present benthic stable carbon and oxygen isotopic (C-13 and O-18) records from five cores from the western equatorial Atlantic (WEA). Together with published benthic isotopic records from nearby cores, we produced a WEA depth transect (similar to 800-2500m). We compare HS1 and YD data from this transect with data from previously published North and South Atlantic cores and demonstrate that the largest negative C-13 excursions occurred in the WEA during these times. Moreover, our benthic O-18 records require the presence of two water masses flowing from the Southern Ocean, bisected by a Northern Component Water (NCW). Given that O-18 is a conservative water mass tracer, we suggest that C-13 was decoupled from water mass composition and does not correspond to simple alternations between northern and southern sourced waters. Instead, C-13 behaved non-conservatively during HS1 and the YD. Consistently with our new Pa-231/Th-230 record from the WEA transect, that allowed the reconstruction of AMOC strength, we hypothesize that the negative C-13 excursions reflect an increase in the residence time of NCW in response to a weakened AMOC, allowing for a marked accumulation of C-13-depleted respired carbon at the mid-depth WEA. (AU)

FAPESP's process: 12/17517-3 - Response of the Western Atlantic Ocean to changes in the Atlantic meridional overturning circulation: from millennial to seasonal variability
Grantee:Cristiano Mazur Chiessi
Support type: Research Program on Global Climate Change - Young Investigators