Living (stained) benthic foraminifera from Southern Brazilian Margin: A comparative study in different soft sediments size fractions and strata

Autor(es)

Santarosa, Ana Claudia Aoki ; Yamashita, Cintia ; Vicente, Thaisa Marques ; Martins, Maria Virginia Alves ; Moreira, Daniel Leite ; de Mello e Sousa, Silvia Helena

• Tipo de documento: Artigo Científico
• Fonte: MARINE MICROPALEONTOLOGY; v. 201, p. 11-pg., 2025-09-03.

Resumo

Living (stained) benthic foraminifera from deep-sea stations in the Southern Brazilian Margin were studied to compare distribution patterns across the 63-125 mu m and > 125 mu m size fractions 0-1 and 1-2 cm intervals. Statistical testsconfirmed the presence of significant differences between the two sediment layers and size fractions. The superficial level showed higher density of specimens and species richness. In addition, the sediment layers show distinct species composition. The most abundant and frequent species in the 0-1 cm were Globocassidulina subglobosa, Epistominella exigua, Alabaminella weddellensis, Reophax sp. 1, Seabrookia curta, Bolivina albatrossi, Reophax tortilis, and Trifarina bradyi. Among the 96 exclusive species from the 1-2 cm, we found: Arenoparrella mexicana, Haplophragmoides fragile, Triloculinella pseudooblonga, Technitella harrisii, and Bolivina pacifica. Regarding the different size fractions, the >125 mu m fraction showed lower density of specimens but higher diversity and the benthic foraminiferal assemblages had an average of 65 % agglutinated and 33 % calcareous species. The most abundant species were Reophax sp. 1, Thurammina sp. 1, Lagenammina sp. 1, Uvigerina peregrina, and Reophax scorpiurus. In the 63-125 mu m size fraction, benthic foraminiferal assemblages comprised 53 % agglutinated and 43 % calcareous species, showing that the proportions of agglutinated species decreased. The most abundant species in the finer fraction were Alabaminella weddellensis, Epistominella exigua, Globocassidulina subglobosa, Seabrookia curta, and Bolivina albatrossi. Based on the statistically different results of the diversity indices, as well as the distinctive composition of species between the two layers and size fractions, we recommend the use of the >63 mu m size fraction and 0-2 cm for future studies on benthic foraminifera in oligotrophic deep-sea areas. (AU)

• Processo FAPESP: 18/00096-1 - Implementação de uma camada de convolução usando multiplicadores aproximados em FPGA para redes neurais convolucionais
• Beneficiário: Leonardo Tavares Oliveira
• Modalidade de apoio: Bolsas no Exterior - Estágio de Pesquisa - Iniciação Científica
• Processo FAPESP: 20/14356-5 - A Bifurcação de Santos: presente e passado
• Beneficiário: Michel Michaelovitch de Mahiques
• Modalidade de apoio: Auxílio à Pesquisa - Programa de Pesquisa sobre Mudanças Climáticas Globais - Temático