Preliminary study on the foraminiferal assemblages from the MEDWAVES cruise

Poster presentation at ATLAS 3rd General Assembly.

A total of 996 foraminiferal specimens corresponding to 23 planktonic species (934 individuals) and 45 benthic species (62 individuals) have been classified from six samples obtained around the Formigas archipelago during the MEDWAVES cruise, between 1,536 mwd and 1,108 mwd. Three main groups are distinguished among the planktonic taxa based on their distribution along the water column: shallow-water species (< 50 mwd), intermediate-water taxa (50 - 100 mwd) and deep-water forms (> 100 mwd). Deep-water forms are dominant in all samples (46% - 73%) and are mostly represented by the temperate species Globorotalia inflata and the subtropical species Gr. truncatulinoides. Intermediate-water species range between 15% and 22% in abundance and mostly correspond to subtropical forms (Orbulina universa and Globigerinella siphonifera) and temperate taxa (Globigerina bulloides). The least abundant planktonic foraminifera are the shallow-water forms (10% - 20%) that live above the permanent thermocline and are mostly represented by symbiont-bearing, tropical Globigerinoides sacculifer. Benthic foraminifers include many species but scarcely represented and correspond to both reworked and in-situ dwelling forms. The most conspicuous species correspond to hyaline taxa (60% - 100%) that are mostly represented by Valvulineria bradyana, Cibicidoides spp., Lagena spp., Hyalinea balthica, Discanomalina coronata, Spirillina limbata and Neolenticulina peregrina. It is remarkable the occurrence of the species Hyrrokkin sarcophaga, a parasitic species common in deep-water corals. Porcellaneous taxa are less frequent and mostly represented by Triloculina tricarinata, Spirosigmoilina sp. and Spirophtalmidium sp. Finally, agglutinate foraminifera are rare and mostly correspond to the species Siphotextularia concava.