The productivity history in the Southwestern Atlantic as inferred from coccolitophore record fot the last 130 kyr

• Autor(a) principal: Leonhardt, Adriana
• Data de Publicação: 2013
• Outros Autores: Toledo, Felipe Antonio de Lima, Coimbra, João Carlos
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da FURG (RI FURG)
• Texto Completo: http://repositorio.furg.br/handle/1/6620
• topic: Paleoceanography; Coccolithophorids; Productivity; Quaternary; Southwestern atlantic; Paleoceanografia; Cocolitoforídeos; Produtividade; Quartenário; Atlântico sudoeste

In this work, fossil assemblages of coccolithophorids, oxygen stable isotopes (Globigerinoides ruber), and radiocarbon dating were used as proxies. The sediment core, obtained on the slope of Campos Basin, was analyzed, comprising the last 130 kyr. The results show that placolith-bearing taxa, such as Gephyrocapsa spp. and Emiliania huxleyi, as well as Florisphaera profunda, which inhabits the lower photic zone, dominated the assemblage during the whole study interval. Over the past 130 kyr, there was a relationship between productivity (based on N ratio) and climate cyclicity. In a general way, it can be said that sensu stricto interglacial stages (MIS 5e and the Holocene) showed low productivity, while the others (MIS 5d-a, 4, 3 and 2) had large fl uctuations. During interglacial-like conditions, a northward shift in the Intertropical Convergence Zone position would take place, along with a weakening of the NE winds associated with the Southern Atlantic Subtropical High and a weakening of the Brazil Current, leading to the maintenance of the water stratifi cation. On the other hand, during glacial-like conditions, the inverse conditions would be favorable to a shallower nutricline, increasing productivity in surface waters. Maximum productivity is achieved between 14-6.5 ky (during deglaciation), which could be a refl ection of the events of the Last Glacial Maximum.