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Eccentricity-induced expansions of Brazilian coastal upwelling zones

2019; Elsevier BV; Volume: 179; Linguagem: Inglês

10.1016/j.gloplacha.2019.05.002

1872-6364

Douglas V.O. Lessa, Thiago Pereira dos Santos, Igor M. Venâncio, Ana Cláudia Aoki Santarosa, Edmundo C. dos Santos, Felipe Antonio de Lima Toledo, Karen Badaraco Costa, Ana Luíza Spadano Albuquerque,

Geological formations and processes

Expansions of coastal upwelling spots along the Brazilian coast were previously reported for Marine Isotope Stage (MIS) 5, but open questions remain regarding the climatic mechanisms and the periodicity of such changes. Based on two marine sediment cores, we provide evidence for multiple intensifications of the upwelling regime off the Southeast Brazilian margin (SBM) during several interglacials and highlight the major role of eccentricity as the responsible forcing. In addition, we show a two-step change in the upwelling regime across the Mid-Brunhes Event (MBE) and an increase in the amplitude of upwelling variability after this climatic transition. Our findings point to substantial modifications of the upwelling regions during several glacial-interglacial transitions that probably altered the regional marine productivity regime and the carbon budget.