Distribution of foraminifera from South Shetland Islands (Antarctic): Ecology and taphonomy

Abstract

The aim of this study was to analyze the distribution of foraminifera of surface sediments from South Shetland Islands (62 S 58 W) in relation to physical parameters. Three sites were analyzed: 1) North of South Shetland Island; 2) Deception Island, and 3) Potter Cove. We have identified 21 species, which were distributed in 13 genera, mainly from the Orders Rotaliida and Trochamminida. There was a predominance of calcareous individuals in Shetland Islands — represented by Cibicides refulgens (Montfort) and in Potter Cove, where Globocassidulina subglobosa (Brady) and Globocassidulina rossensis (Kennett) were the main representatives. In Deception Island, the proportion of calcareous individuals was matched by that of agglutinated specimens, represented by Trochammina inflata (Montagu) and Miliammina fusca (Brady). Foraminifers also exhibited different lifestyles, microhabitats, feeding strategies, and taphonomy. A strong correlation between microfauna and physical parameters was observed at the three sites. Assemblage I consisted on Cibicides refulgens, Cibicides aknerianus (d’Orbigny), Melonis affine (Reuss) and Melonis pompilioides (Fichtel and Moll), which were all distributed along the bathymetric gradient and the clay sediments. Assemblage II comprised Trochammina inflata, Miliammina fusca and Cassidulinoides parkerianus (Brady), which were correlated with a higher content of gravel. And assemblage III included individuals of Globocassidulina subglobosa and Globocassidulina sp., both correlated with higher sand content. This work contributes to increasing our knowledge about the distribution of foraminifera in the Antarctic zone, which is a largely understudied region. The new data could be useful for both determining environmental conditions and establishing bioindicators of pollution and anthropogenic activity. In addition, the correlations with climate events might contribute to the development of new tools for monitoring climate variations.