Recent benthic foraminifers from the South Atlantic shelf of Argentina

Abstract

The aim of this study was to determine foraminiferal associations from recent sediments of Argentina's continental shelf (39-41°S, 59-61°W; 11-70 m) and assess their relationship to physicochemical parameters. From 20 samples, all dominated by sandy sediments (>80% sand), 44 species of foraminifers were identified, most commonly Buccella peruviana. Recovered foraminiferal tests were generally well preserved, with morphologies indicating predominantly epifaunal, free-living detritivores from well-oxygenated waters. Multivariate analyses showed a strong correlation between foraminiferal assemblages and four zones related to physicochemical parameters. Zone I included the offshore samples from depths of 40-70 m where waters were slightly colder and more saline. Zone II samples were all collected from depths of 30-40 m that were intermediate in temperature. Zone III occurred at 20-40 m depth where sediments were characterized by some gravel content. Zone IV included the inshore sites (<20 m) offshore from the Rio Colorado delta. This work contributes to the knowledge of foraminifers on Argentina's continental shelf, complementing earlier studies of foraminiferal distributions and ecology from the region.