Significance of Globigerina Bulloides D’orbigny: A Foraminiferal Proxy for Palaeomonsoon and Past Upwelling Records

Abstract

The planktic foraminiferal species Globigerina bulloides is an important proxy for inferring past upwelling intensity and related monsoonal variability. Besides its relative abundance, the stable isotopic composition of its test has been extensively used for surface water temperature estimation and paleoproductivity changes. Enough confusion still remains regarding identification of this taxon due to wide range of variation in morphological parameters. Due to this, several species have been erected including Globigerina quadrilatera, Globigerina megastoma, Globigerina bermudezi, Globigerina cariacoensis and Globigerina riveroe. Some are considered to be phenotypic variants by various authors whilst separate species by others. Considering this, we strongly favour picking up of single morphotype of Globigerina bulloides for isotopic analyses and advocate for a detailed genetic study of various morphotypes to get enlightened picture of the species concept.