| Full text | |
| Author(s): |
Nagai, Renata H.
;
Chiessi, Cristiano M.
;
Kuhnert, Henning
;
Sousa, Silvia H. M.
;
Wainer, Ilana E. K. C.
;
Figueira, Rubens C. L.
;
Mahiques, Michel M.
Total Authors: 7
|
| Document type: | Journal article |
| Source: | GEO-MARINE LETTERS; v. 40, n. 6, p. 11-pg., 2020-01-03. |
| Abstract | |
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) | |
| FAPESP's process: | 10/09983-9 - Sea surface temperature changes in the western South Atlantic and precipitation variability in southeastern South America since the Last Glacial Maximum |
| Grantee: | Cristiano Mazur Chiessi |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 09/01594-6 - Productivity changes in the south-southeastern Brazilian continental shelf, during Mid and Late Holocene: a multiproxy approach |
| Grantee: | Renata Hanae Nagai |
| Support Opportunities: | Scholarships in Brazil - Doctorate |
| FAPESP's process: | 12/17517-3 - Response of the Western Atlantic Ocean to changes in the Atlantic meridional overturning circulation: from millennial to seasonal variability |
| Grantee: | Cristiano Mazur Chiessi |
| Support Opportunities: | Research Program on Global Climate Change - Young Investigators |