Autor(es)

Nagai, Renata H. ; Chiessi, Cristiano M. ; Kuhnert, Henning ; Sousa, Silvia H. M. ; Wainer, Ilana E. K. C. ; Figueira, Rubens C. L. ; Mahiques, Michel M.

• Tipo de documento: Artigo Científico
• Fonte: GEO-MARINE LETTERS; v. 40, n. 6, p. 11-pg., 2020-01-03.

Resumo

Here, we present two high temporal resolution Holocene sea surface temperature (SST) and salinity (SSS) reconstructions for the SW Atlantic. Mg/Ca data together with the oxygen isotopic composition (delta O-18) of a shallow dwelling planktonic foraminifera species (Globigerinoides ruber(pink)). Two marine sediment cores collected at similar to 25 degrees S are used to assess mid- to late Holocene sea surface hydrographic conditions in the continental shelf of the South Brazilian Bight. Our results show multi-centennial-scale changes of up to 2.7 degrees C in SST and 0.8 parts per thousand in ice volume corrected seawater delta O-18 (a proxy for SSS, indicating changes of up to 2 salinity units). In phase, multicentennial-scale negative SST and SSS incursions were interpreted to indicate shelf-break upwelling events and the northward intrusion of the Plata Plume Water (PPW) under a strengthened Brazil Current (BC) flow. The latitudinal SST gradient between our two records (Delta SST7616-7610), applied here as a proxy for the BC strength, supports the existing hypothesis of antiphase between the BC and the North Brazil Current strength during the last 7 ka. Positive Delta SST(7616-7610)values suggest the presence of the PPW at latitudes of up to 25.5 degrees S, while negative Delta SST(7616-7610)values (centred at around 5.4, 4.3, 2.2 and 1.3 cal ka BP) occurring synchronously with cold events in the Northern Hemisphere suggests that the Atlantic Meridional Overturning Circulation played a central role in the SW Atlantic mid- to late Holocene surface hydrographic conditions. (AU)

• Processo FAPESP: 10/09983-9 - Mudanças na temperatura da superfície do mar no oeste do Atlântico Sul e variabilidade na precipitação no sudeste da América do Sul desde o Último Máximo Glacial
• Beneficiário: Cristiano Mazur Chiessi
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 09/01594-6 - Variações na produtividade da plataforma continental sul-sudeste do Brasil, no Holoceno Médio e Tardio: Uma abordagem "multiproxy"
• Beneficiário: Renata Hanae Nagai
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 12/17517-3 - Resposta da porção oeste do Oceano Atlântico às mudanças na circulação meridional do Atlântico: variabilidade milenar a sazonal
• Beneficiário: Cristiano Mazur Chiessi
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Jovens Pesquisadores