Thermal response of the western tropical Atlantic to slowdown of the Atlantic Meridional Overturning Circulation

Crivellari, Stefano; Chiessi, Cristiano Mazur; Kuhnert, Henning; Häggi, Christoph; Mollenhauer, Gesine; Hefter, Jens; Portilho-Ramos, Rodrigo Costa; Schefuß, Enno; Mulitza, Stefan

doi:10.1016/j.epsl.2019.05.006

Cited by 21 publications

(9 citation statements)

References 56 publications

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“…During the late-glacial period and Heinrich stadial 1 interval, it is very well documented that large areas in adjacent South America experienced wetter conditions due to a noticeable strengthening of the precipitation associated with the South American Monsoon System (SAMS) (Cruz et al, 2005;Stríkis et al, 2015Stríkis et al, , 2018Novello et al, 2017;Gu et al, 2018). The increased precipitation volume would be drained by the Paraná Basin and subsequently discharged into the ocean by La Plata River, mixing a continental freshwater influence with Subantarctic Shelf waters, similar to what occurs today (Burone et al, 2013).…”

Section: Discussionmentioning

confidence: 96%

Contrasting late-glacial paleoceanographic evolution between the upper and lower continental slope of the western South Atlantic

Luz

Santos

Eglinton³

et al. 2020

Clim. Past

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Abstract. The number of sedimentary records collected along the Brazilian continental margin has increased significantly in recent years, but relatively few are located in shallow waters and register paleoceanographic processes in the outer shelf–middle slope prior to 10–15 ka. For instance, the northward flow up to 23–24∘ S of cold and fresh shelf waters sourced from the Subantarctic region is an important feature of current hydrodynamics in the subtropical western South Atlantic Ocean, and yet limited information is available for the long-term changes of this system. Herein, we considered a suite of organic and inorganic proxies – alkenones-derived sea surface temperature (SST), δD-alkenones, δ18O of planktonic foraminifera, and ice-volume free seawater δ18OIVF−SW – in sediment from two cores (RJ-1501 and RJ-1502) collected off the Rio de Janeiro Shelf (SE Brazilian continental shelf) to shed light on SST patterns and relative salinity variations since the end of the last glacial cycle in the region and the implications of these processes over a broader spatial scale. The data indicate that, despite the proximity (∼40 km apart) of both cores, apparently contradictory climatic evolution occurred at the two sites, with the shallower (deeper) core RJ-1501 (RJ-1502) showing consistently cold (warm) and fresh (salt) conditions toward the Last Glacial Maximum (LGM) and last deglaciation. This can be reconciled by considering that the RJ-1501 core registered a signal from mid- to high latitudes on the upper slope off Rio de Janeiro represented by the influence of the cold and fresh waters composed of Subantarctic Shelf Water and La Plata Plume Water transported northward by the Brazilian Coastal Current (BCC). The data from core RJ-1502 and previous information for deep-cores from the same region support this interpretation. In addition, alkenone-derived SST and δ18OIVF−SW suggest a steep thermal and density gradient formed between the BCC and Brazil Current (BC) during the last climate transition which, in turn, may have generated perturbations in the air–sea heat flux with consequences for the regional climate of SE South America. In a scenario of future weakening of the Atlantic Meridional Overturning Circulation, the reconstructed gradient may become a prominent feature of the region.

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Section: Discussionmentioning

confidence: 96%

Contrasting late-glacial paleoceanographic evolution between the upper and lower continental slope of the western South Atlantic

Luz

Santos

Eglinton³

et al. 2020

Clim. Past

View full text Add to dashboard Cite

show abstract

“…Os eventos Heinrich Stadials provocaram mudanças marcantes no contraste termal superficial entre os hemisférios, isto é, resfriamento nas altas latitudes do Hemisfério Norte e aquecimento em vastas porções do Hemisfério Sul (Figura 1, itens 4 e 5) (BARKER et al, 2009;CHIESSI et al, 2015;CRIVELLARI et al, 2019;MEIER et al, 2021). Tal contraste termal se deu em virtude da redução da capacidade da AMOC de transportar calor em direção ao Atlântico Norte, e, como consequência, o calor ficou retido no Hemisfério Sul.…”

Section: O Oceano Atlântico a Temperatura E O Ciclo Do Carbonounclassified

Os Oceanos: Lições do Passado para um Futuro Sustentável

Campos¹,

Crivellari²,

Chiessi³

2022

Agendas Locais E Globais Da Sustentabilidade: Ciência, Tecnologia, Gestão E Sociedade

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“…Jennerjahn et al, 2004;Lessa et al, 2017;Mulitza et al, 2017;Portilho-Ramos et al, 2015;Rühlemann et al, 1999). Cores located adjacent to the semi-arid NE Brazil have allowed for several investigations addressing the interplay between changes in the Atlantic Meridional Overturning Circulation (AMOC), the sea surface temperature (SST) of the tropical Atlantic, and the continental climate (in terms of precipitation and vegetation cover) in centennial to millennial time-scales (Behling et al, 2000;Bouimetarhan et al, 2018;Burckel et al, 2015;Crivellari et al, 2019;Venancio et al, 2018;Zhang et al, 2015Zhang et al, , 2017.…”

Section: Introductionmentioning

confidence: 99%

Contrasting late-glacial paleoceanographic evolution between the upper and lower continental slope of the western South Atlantic

Luz¹,

Santos²,

Eglinton³

et al. 2020

Preprint

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show abstract

Thermal response of the western tropical Atlantic to slowdown of the Atlantic Meridional Overturning Circulation

Cited by 21 publications

References 56 publications

Contrasting late-glacial paleoceanographic evolution between the upper and lower continental slope of the western South Atlantic

Contrasting late-glacial paleoceanographic evolution between the upper and lower continental slope of the western South Atlantic

Os Oceanos: Lições do Passado para um Futuro Sustentável

Contrasting late-glacial paleoceanographic evolution between the upper and lower continental slope of the western South Atlantic

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