The Southern Ocean is an important region for climate research where primary productivity is iron limited. Despite numerous studies, the role of iron availability in the phytoplankton speciatiou is still poorly understood. In this study, the bioavailability of several organic iron complex was measured using natural phytoplankton and compared to the bioavailability of four strains representing the major taxonomic plankton groups in the Southern Ocean (Bacillariophyta and Prymnesiophytes). Iron bioavailability was measured on filtered (0.2μm) and ultrafiltered (0.02μm) waters collected from three process stations (two at 46°and one at 54°S) south of Tasmania (Australia) during the austral summer. Since trace metal chemical speciation usually best describes its bioavailability, iron-organic speciation will be measured by competitive ligand exchange adsorptive stripping voltammetry (CLE-AdSV). Additional laboratory measurements of growth rate, photosynthetic yield, cellular iron quota for each of the four species studied, provided a quantitative measure of iron bioavailability in the Southern Ocean.
bioavailability iron phytoplankton primary productivity Southern Ocean
C. S. Hassler V. Schoemann D. Lannuzel A. R. Bowie T. Remenyi S. Blackburn E. C. V. Butler
CSIRO Atmospheric and Marine Research, GPO Box 1538, Hobart 2001, Australia Ecologie des Systemes Aquatiques, Universite Libre de Bruxelles, Bruxelles 1050, Belgium Ecologie des Systemes Aquatiques, Universite Libre de Bruxelles, Bruxelles 050, Belgiu Antarctic Cli Antarctic Climate and Ecosystems CRC, University of Tasmania, Private Bag 80, Hobart 2001, Australia CSIRO Atmospheric and Marine Research, GPO Box 1538, Hobart 2001, Australia Antarctic Climate and Ec