Tracing latitudinal gradient, river discharge and water masses along the Subtropical South American coast using benthic foraminiferal assemblages.

Published in Brazilian Journal of Biology, v. 72(3):723-759

Eichler, P., Rodrigues, A.R., Eicher, B.B., Braga, E.S. and Campos, E.J.D.

Publication year 2012
  • Programa de Pós-Graduação em Geodinâmica e Geofísica - PPGG, Centro de Ciências Exatas e da Terra, Universidade Federal do Rio Grande do Norte - UFRN, Campus Universitário, Lagoa Nova, CEP 59072-970, Natal, RN, Brazil
  • nstituto Oceanográfico, Universidade de São Paulo - USP, Praça do Oceanográfico, 191, Cidade Universitária, CEP 05508-120, São Paulo, SP, Brazil


IAI Program


IAI Project CRN3070


More than 30% of Buccella peruviana (D'Orbigny), Globocassidulina crassa porrecta (Earland & Heron-Allen), Cibicides mackannai (Galloway & Wissler) and C. refulgens (Montfort) indicate the presence of cold Sub Antarctic Shelf Water in winter, from 33.5 to 38.3º S, deeper than 100 m, in the southern part of the study area. In summer, the abundance of this association decreases to less than 15% around 37.5-38.9º S where two species (Globocassidulina subglobosa (Brady), Uvigerina peregrina (Cushman) take over. G. subglobosa, U. peregrina, and Hanzawaia boueana (D'Orbigny) are found at 27-33º S in both seasons in less than 55 m deep in the northern part, and are linked with warm Subtropical Shelf Water and Tropical Water. Freshwater influence was signalized by high silicate concentration and by the presence of Pseudononion atlanticum (Cushman), Bolivina striatula (Cushman), Buliminella elegantissima (D'Orbigny), Bulimina elongata (D'Orbigny), Elphidium excavatum (Terquem), E. poeyanum (D'Orbigny), Ammobaculites exiguus (Cushman & Brönnimann), Arenoparrella mexicana (Kornfeld), Gaudryina exillis (Cushman & Brönnimann), Textularia earlandi (Parker) and thecamoebians in four sectors of the shelf. The presence of Bulimina marginata (D'Orbigny) between 34.1-32.8º S in the winter and 34.2-32.7º S in the summer indicates that the influence of the Subtropical Shelf Front on the sediment does not change seasonally, otherwise, the presence of Angulogerina angulosa (Williamson) in the winter, only in Mar del Plata (38.9º S), show that Malvinas currents are not influencing the sediment in the summer.