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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.)

Understanding the mechanisms behind high glacial productivity in the southern Brazilian margin

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Author(s):
Portilho-Ramos, Rodrigo da Costa [1, 2] ; Lima Pinho, Taina Marcos [2, 3] ; Chiessi, Cristiano Mazur [3] ; Barbosa, Catia Fernandes [4]
Total Authors: 4
Affiliation:
[1] Univ Bremen, MARUM Ctr Marine Environm Sci, Leobener Str, D-28359 Bremen - Germany
[2] Univ Sao Paulo, Inst Geosci, Rua Lago 562, BR-05508080 Sao Paulo - Brazil
[3] Univ Sao Paulo, Sch Arts Sci & Humanities, Rua Arlindo Bettio 1000, BR-03828000 Sao Paulo - Brazil
[4] Univ Fed Fluminense, Dept Geoquim, Rua Outeiro Sao Joao Baptista S-N, BR-24020141 Niteroi, RJ - Brazil
Total Affiliations: 4
Document type: Journal article
Source: Climate of the Past; v. 15, n. 3, p. 943-955, MAY 27 2019.
Web of Science Citations: 0
Abstract

This study explores the mechanisms behind the high glacial productivity in the southern Brazilian margin (SBM) during the last 70 kyr using planktonic foraminifera assemblage and subsurface temperature information derived using the modern analogue technique. We show that enhanced glacial productivity was driven by the synergy of two mechanisms operating in different seasons: (i) enhanced productivity in the upwelling region during short austral summer events; and (ii) the persistent presence of the Plata Plume Water (PPW) due to prolonged austral winter conditions. We suggest that the upwelling systems in the southern Brazilian margin were more productive during the last glacial period due to the enhanced Si supply for diatom production by high-Si thermocline waters preformed in the Southern Ocean. We hypothesize that orbital forcing did not have a major influence on changes in upwelling during the last glacial period. However, the more frequent northward intrusions of the Plata Plume Water were modulated by austral winter insolation at 60 degrees S via changes in the strength of alongshore southwesterly winds. After the Last Glacial Maximum, the reduced Si content of thermocline waters decreased upwelling productivity, while lower austral winter insolation decreased the influence of the Plata PlumeWater over the southern Brazilian margin, reducing regional productivity. (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 Opportunities: Research Program on Global Climate Change - Young Investigators