Study of fossil and recent foraminifera and marine microplankton from the Beagle Channel (South America) using statistical analysis.

PÉREZ, S.; BERNASCONI, E.; CANDEL, M.S.; BORROMEI, A.M.

Congreso; 4th Palaeontological Virtual Congress; 2023

A comparative study on the distribution of Holocene and recent benthic foraminifera, as well as organic-walled microplankton (mainly dinocysts and acritarchs) was performed in samples from both sediment surface and excavation carried out from the surface down to 70 cm-depth in the Beagle Channel, using multivariate analyses. Late Holocene (group A) and recent (group B) samples were used to perform a non-metric multidimensional scaling (nMDS) analysis, an analysis of similarities (ANOSIM), and a similarity percentage (SIMPER) analysis. The nMDS analysis showed significant dissimilarity between groups A and B, as well as dissimilarity within group B (subgroups B1, B2, B3, and B4). According to ANOSIM and SIMPER analysis, this dissimilarity is due to the contribution of species with greater affinity for either the fossil (3 foraminifera and 4 marine microplankton) or recent (3 foraminifera and 2 marine microplankton) samples. The foraminifera species with greater affinity with the Group A are Criboelphidium excavatum, Elphidium macellum, and Elphidium alvarezianum and the marine microplankton are Brigantedinium simplex, Palaeostomocystis subtilitheca, P. fritilla, and B. cariacoense. On the other hand, the foraminifera species with a greater affinity with the group B are Cibicidoides dispars, Buccella peruviana, and Cibicides aknerianus and the marine microplankton species are Pentapharsodinium dalei and Selenopemphix quanta. This integrated analysis is useful in demonstrating the similarities and/or dissimilarities in the distribution of samples based on the relative abundance of taxa.