Changes in surface hydrography at the western tropical Atlantic during the Younger Dryas

Venancio, Igor Martins; Shimizu, M. H.; Santos, Thiago Pereira dos; Lessa, Douglas Villela de Oliveira; Portilho-Ramos, Rodrigo Costa; Chiessi, Cristiano Mazur; Crivellari, Stefano; Mulitza, Stefan; Kuhnert, Henning; Tiedemann, Ralf; Vahlenkamp, Maximilian; Bickert, Torsten; Sampaio, Gilvan; Albuquerque, Ana Luíza Spadano; Veiga, Sandro F.; Nobre, Paulo; Nobre, Carlos A.

doi:10.1016/j.gloplacha.2019.103047

Cited by 13 publications

(11 citation statements)

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“…The intriguing divergence between Ba/Ca and δ 18 O sw signals in the western tropical Atlantic during MIS5 was also observed for the last termination. Venancio et al (2020) showed that Ba/Ca of core GL-1248 increased during the Younger Dryas (YD), while several δ 18 O sw records for the western tropical Atlantic showed increases or no clear changes in the values, with the exception of the record from core CDH-86 (Nace et al, 2014) that showed a decrease in δ 18 O sw during the YD. The increases in δ 18 O sw in the western tropical Atlantic were attributed to a reduction of the cross-equatorial transport of saline waters due to a weakening of the NBC linked to slowdowns of the AMOC during the YD (Weldeab et al, 2006;Venancio et al, 2020).…”

Section: Discussionmentioning

confidence: 99%

“…Venancio et al (2020) showed that Ba/Ca of core GL-1248 increased during the Younger Dryas (YD), while several δ 18 O sw records for the western tropical Atlantic showed increases or no clear changes in the values, with the exception of the record from core CDH-86 (Nace et al, 2014) that showed a decrease in δ 18 O sw during the YD. The increases in δ 18 O sw in the western tropical Atlantic were attributed to a reduction of the cross-equatorial transport of saline waters due to a weakening of the NBC linked to slowdowns of the AMOC during the YD (Weldeab et al, 2006;Venancio et al, 2020). The results from our study and previous published works (Bahr et al, 2013;Venancio et al, 2020) show that Ba/Ca is a reliable proxy to track past changes fluvial discharge.…”

Section: Discussionmentioning

confidence: 99%

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Tropical South American Rainfall Response to Dansgaard-Oeschger Stadials of Marine Isotope Stage 5

et al. 2022

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Tropical precipitation patterns will most likely be altered by future climate change, with major socioeconomic consequences for human populations that are highly reliant on water availability for subsistence like populations in northeastern (NE) Brazil. Socioeconomic consequences may be particularly disruptive in the occurrence of abrupt climate change. Understanding the response of tropical precipitation to abrupt climate change is a crucial task for improving future projections and devising adaptation policies. Past abrupt climate change events such as the Dansgaard-Oeschger (DO) cycles may provide relevant insights regarding the dynamics of the climate system under this type of climate change. Here we present a paleoceanographic reconstruction off NE Brazil based on geochemical analyses (stable oxygen isotopes, Mg/Ca and Ba/Ca) performed in planktonic foraminifera, that focus on DO stadials of Marine Isotope Stage 5 (MIS5, 130–71 ka). Our new Ba/Ca record shows increases in fluvial discharge linked to enhanced continental precipitation over NE Brazil during DO stadials of MIS5. Tropical precipitation patterns were altered with enhanced rainfall in NE Brazil during DO stadials as a consequence of a southward displacement of the Intertropical Convergence Zone, which, in turn, was likely a response to changes in ocean heat transport and sea ice cover, as highlighted by recent climate model simulations. The results presented here provide useful information on how abrupt climate change can impact tropical rainfall, which is crucial for tropical societies in order to delineate strategies to cope with future climate change.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Tropical South American Rainfall Response to Dansgaard-Oeschger Stadials of Marine Isotope Stage 5

et al. 2022

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“…The authors suggested that, despite Agulhas Current SSS increases during HS, a weakening of this current would result in reduced salt transport by the AL into the South Atlantic. Another factor that could account for the smaller M125-95-3 excursions is the dilution of SSS via direct precipitation (e.g., PORTILHO-RAMOS et al, 2017;VENANCIO et al, 2020). Indeed, CAMPOS et al (2019b) showed higher atmospheric precipitable water over our core site during HS.…”

Section: Resultsmentioning

confidence: 66%

“…On the other hand, CAMPOS et al (2020, under review, Chapter 5) showed that, despite higher continental precipitation, the upper water column of our core site was not affected by river-born nutrients, indicating that the low-salinity river plume did not substantially affected the upper water column of our core site. Furthermore, considering BAHR et al (2013) andVENANCIO et al (2020), the  18 Oivc-ssw may not faithfully record changes in riverine input. Thus, we cannot affirm that our negative  18 Oivc-ssw excursions during HS4 and HS1 are related to increased input of low-salinity river water.…”

Section: Resultsmentioning

confidence: 98%

Millennial-scale variability in eastern South American climate and western South Atlantic circulation during the last 70,000 years

Campos¹

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“…However, they are located under the influence of the Intertropical Convergence Zone (ITCZ), a global convective belt over the oceans associated to the ascending branch of the Hadley cell and to the convergence of the NE and SE trade winds (Marshall, 2014;Schneider et al, 2014). The ITCZ annual mean latitudinal position is around 5ºN and, despite its southward displacements during HS events (Mulitza et al, 2017;Portilho-Ramos et al, 2017;Mendes et al, 2019;Venancio et al, 2020;Zhang et al, 2017), it is unlikely to have influenced the SFRB. Indeed, the northernmost portion of the SFRB is located at ca.…”

Section: Americamentioning

confidence: 99%

Changes in hydroclimate and vegetation in the São Francisco river drainage basin during the last 45000 years

Ferreira¹

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I thank my colleagues at the Paleoceanography and Paleoclimatology Laboratory (P2L) at the School of Arts, Sciences and Humanities, and the Institute of Geosciences for interesting academic discussions and meetings. Special thanks go to Dr. Marília Campos for the support, as well as to Dr. Dailson Bertassoli and MSc. Thomas Akabane for the company during the fieldtrip in the São Francisco River Basin -crossing this river from its headlands to its mouth was an unforgettable experience.I thank my supervisor abroad, Dr. Enno Schefuß for his patience and help. Special thanks go to Ralph Kreutz for the technical support. I also thank all my colleagues at the MARUM -Center of Marine Environmental Science (University of Bremen, Germany) who helped me with laboratory procedures. Many thanks go to MSc. Débora Raposo and MSc. Jéssica Resende for the helping me during my stay in Bremen. I am grateful to the infrastructure of the University of São Paulo that made possible my Master's degree. I thank CAPES for the MSc. scholarship (grant 88882.328049/2019-01), as well as for two grants that partially financed this study (grants 564/2015 and 88881.313535/2019-01). Other funding agencies are also thanked for partially financing this

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Changes in surface hydrography at the western tropical Atlantic during the Younger Dryas

Cited by 13 publications

References 59 publications

Tropical South American Rainfall Response to Dansgaard-Oeschger Stadials of Marine Isotope Stage 5

Tropical South American Rainfall Response to Dansgaard-Oeschger Stadials of Marine Isotope Stage 5

Millennial-scale variability in eastern South American climate and western South Atlantic circulation during the last 70,000 years

Changes in hydroclimate and vegetation in the São Francisco river drainage basin during the last 45000 years

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