Distribution of calcareous nannoplankton near the Subtropical Convergence, south of Tasmania, Australia

Abstract

The floral composition of living calcareous nannoplankton collected from surface waters near the Subtropical Convergence (STC), offshore south-eastern Tasmania, in January 1994 is presented. Emiliania huxleyi represented more than 90% of all coccolithophorids. Scanning electron microscopy showed a substantial increase in intraspecific variation of E. huxleyi, and in variation in coccolith size of Calcidiscus leptoporus, E. huxleyi type A and C. leptoporus (small), north of the STC.

It is postulated that the percentage abundance of these taxa may be used to determine the position andlor shift of the STC zone through time, and therefore may be of use for palaeoceanographic studies.