Seminar Details

Global phylogeography of Globigerina bulloides and the geochemical signatures of Arabian Sea genotypes: implications for paleoenvironmental reconstruction




Prof. Kate Darling - School of Geography & Sustainable Development, University of St Andrews, Scotland


Reconstruction of past oceanic and climatic conditions relies heavily upon the geochemical signatures found within calcitic shells of planktonic foraminifera, since their stable isotopic and elemental composition reflect the physio-chemical environment in which they are formed. It is therefore important to obtain a thorough understanding of the relationship between the ecology of a foraminiferal morphospecies and its shell geochemistry. This relationship is based on the assumption that each foraminiferal morphospecies represents a genetically continuous species with a unique habitat preference. However, many morphologically defined species have been found to represent a mixed assemblage of genetic types which have distinct biogeographic distributions and ecologies. Some of these genotypes can be distinguished in fossil assemblages by using subtle morphological differences, but the paleoceanographically important morphospecies Globigerina bulloides appears to have genotypes with morphologically similar shells (cryptic biological species). This talk will explore the modern global biogeography and ecology of the Globigerina bulloides cryptic biological species and whether their presence in mixed assemblages affects the utilization of their shell geochemistry for the reconstruction of palaeoenvironments.

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