Distribution of living planktonic foraminifera in relation to oceanic processes on the southeastern continental Brazilian margin (23 degrees S-25 degrees S and 40 degrees W-44 degrees W)

Autor(es)

Sousa, S. H. M. ^[1] ; de Godoi, S. S. ^[1] ; Amaral, P. G. ^[1] ; Vicente, T. M. ^[1] ; Martins, M. V. A. ^{[2, 3]} ; Sorano, M. R. G. S. ^[1] ; Gaeta, S. A. ^[1] ; Passos, R. F. ^[1] ; Mahiques, M. M. ^[1]

Afiliação do(s) autor(es)

^[1] Cidade Univ Butanta, Inst Oceanog, Dept Oceanog Fis Quim & Geol, BR-05508120 Sao Paulo - Brazil

^[2] Univ Estado Rio de Janeiro, Dept Estratig & Paleontol, Fac Geol, BR-20550013 Rio De Janeiro, RJ - Brazil

^[3] Univ Aveiro, Dept Geociencias, GeoBioTec, CESAM, P-3810193 Aveiro - Portugal

• Tipo de documento: Artigo Científico
• Fonte: CONTINENTAL SHELF RESEARCH; v. 89, n. SI, p. 76-87, OCT 15 2014.
• Citações Web of Science: 5

Resumo

The vertical distribution (0 to 100 m) of planktonic foraminifera was investigated based on 40 tow samples that were collected in eight stations, during the austral summer of 2002, in a geographically restricted area (23 degrees S-25 degrees S and 40 degrees W-44 degrees W) on the southeastern Brazilian continental margin. Species' abundances are low (less than 10 specimens/m(3)), which is typical of an oligotrophic area. The foraminifera assemblage is mainly composed of warm water species (Globigerinoides ruber white and pink forms), with a predominance of spinose and symbiont-bearing species. Temperature and inorganic nutrient enrichment of the surface are the main factors that control foraminiferal abundance and diversity; nevertheless salinity can also influence the ecological descriptors. The role of the deep chlorophyll maximum (DCM) in the distribution of foraminifera is not always clear, but the increase in the abundance of G. ruber (white and pink) seems to be related to a deeper DCM, and high salinities (S > 36.5). The ecological habitat of these species is affected by the depth of the mixed layer, with a predominance of the white form in deeper layers. Increases in the foraminiferal diversity are related to the dynamics of the Brazil Current system, which displaces the area of high productivity in the euphotic zone off the coast. The abundances of Globigerina bulloides, Globigerina falconensis, Globigerinella calida and Globigerinella siphonifera follow the nutrient enrichment of the surface water mass, corroborating the usefulness of these species as paleoproductivity proxies in the study area. These data confirm the use of diversity measurements and assemblages composition for reconstructing past water column structures in subtropical oceans. (C) 2013 Elsevier Ltd. All rights reserved. (AU)

• Processo FAPESP: 02/06633-0 - Avaliação da utlizacao de foraminíferos planctônicos como indicadores paleoceangraficos no Quaternário do Atlântico Sudoeste
• Beneficiário: Silvia Helena de Mello e Sousa
• Linha de fomento: Auxílio à Pesquisa - Regular