Meridional changes in the South Atlantic Subtropical Gyre during Heinrich Stadials

Author(s)

Pinho, Taina M. L. ^[1] ; Chiessi, Cristiano M. ^[2] ; Portilho-Ramos, Rodrigo C. ^[3] ; Campos, Marilia C. ^[1] ; Crivellari, Stefano ^[2] ; Nascimento, Rodrigo A. ^[4] ; Albuquerque, Ana L. S. ^[4] ; Bahr, Andre ^[5] ; Mulitza, Stefan ^[3]

Affiliation

^[1] Univ Sao Paulo, Inst Geosci, Sao Paulo - Brazil

^[2] Univ Sao Paulo, Sch Arts Sci & Humanities, Sao Paulo - Brazil

^[3] Univ Bremen, MARUM Ctr Marine Environm Sci, Bremen - Germany

^[4] Fluminense Fed Univ, Grad Program Geochem, Niteroi, RJ - Brazil

^[5] Heidelberg Univ, Inst Earth Sci, Heidelberg - Germany

• Document type: Journal article
• Source: SCIENTIFIC REPORTS; v. 11, n. 1 MAY 3 2021.
• Web of Science Citations: 0

Abstract

Subtropical ocean gyres play a key role in modulating the global climate system redistributing energy between low and high latitudes. A poleward displacement of the subtropical gyres has been observed over the last decades, but the lack of long-term monitoring data hinders an in-depth understanding of their dynamics. Paleoceanographic records offer the opportunity to identify meridional changes in the subtropical gyres and investigate their consequences to the climate system. Here we use the abundance of planktonic foraminiferal species Globorotalia truncatulinodes from a sediment core collected at the northernmost boundary of the South Atlantic Subtropical Gyre (SASG) together with a previously published record of the same species from the southernmost boundary of the SASG to reconstruct meridional fluctuations of the SASG over last ca. 70 kyr. Our findings indicate southward displacements of the SASG during Heinrich Stadials (HS) 6-4 and HS1, and a contraction of the SASG during HS3 and HS2. During HS6-4 and HS1, the SASG southward displacements likely boosted the transfer of heat to the Southern Ocean, ultimately strengthening deep-water upwelling and CO2 release to the atmosphere. We hypothesize that the ongoing SASG poleward displacement may further increase oceanic CO2 release. (AU)

• FAPESP's process: 18/15123-4 - Past perspectives on tipping elements of the climate system: the Amazon Rainforest and the Atlantic Meridional Overturning Circulation (PPTEAM)
• Grantee: Cristiano Mazur Chiessi
• Support Opportunities: Research Grants - Research Program on Global Climate Change - Young Investigators - Phase 2
• FAPESP's process: 19/25179-0 - Penultimate glacial-to-interglacial transition in Northeastern South America and the adjacent ocean
• Grantee: Marília de Carvalho Campos Garcia
• Support Opportunities: Scholarships in Brazil - Post-Doctorate
• FAPESP's process: 19/24349-9 - Assessing the effects of past and future climate change on Amazonian biodiversity (CLAMBIO)
• Grantee: Cristiano Mazur Chiessi
• Support Opportunities: BIOTA-FAPESP Program - Regular Research Grants
• FAPESP's process: 16/10242-0 - Occurrence and impact of the mega-South Atlantic Convergence Zone over the eastern South America during the last glacial period: a paleoceanographic approach
• Grantee: Marília de Carvalho Campos Garcia
• Support Opportunities: Scholarships in Brazil - Doctorate
• FAPESP's process: 19/10642-6 - Response of the upper water column at the origin of the Brazil Current to slowdown events of the Atlantic Meridional Ocean Circulation during the last 80 ka
• Grantee: Tainã Marcos Lima Pinho
• Support Opportunities: Scholarships in Brazil - Master