| Texto completo | |
| 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.
Número total de Autores: 7
|
| 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 |