University Of Tasmania

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Molecular and pigment studies of the picophytoplankton in a region of the Southern Ocean (42-54 degrees S, 141-144 degrees E) in March 1998

journal contribution
posted on 2023-05-16, 13:59 authored by Wilmotte, A, Demonceau, C, Goffart, A, Hecq, JH, Demoulin, V, Crossley, AC
Seven filtered seawater samples (depths between 30 and 55 m) collected during the SAZ project of the Austral summer of 1997-1998 were used for a simultaneous study of the picophytoplankton pigments based on high-performance liquid chromatography (HPLC) analyses and flow cytometry, and of the molecular diversity of the picophytoplankton based on their rDNA sequences. The sampling sites could be divided into three temperature zones, distinguished by their proximity to the Sub-Antarctic and Polar Fronts. HPLC analysis of total chlorophylls and carotenoids showed fairly low phytoplankton concentrations (77-262 ng chl a l-1), with minimal values of the pigments in the two samples of the Polar Front Zone around 54°S (water temperature of 4°C at time of collection). In this zone, a similar decrease of particles, identified as cyanobacteria on the basis of their fluorescence, was observed by flow cytometry. Sequences very similar to the 16S rDNA sequence of Synechococcus WH8103 were present in all samples. This Synechococcus genotype is thus found in the Southern Ocean in addition to the Atlantic and Pacific locations where it has been previously observed. The yield of PCR products was lower in the two samples taken in the Polar Front Zone, showing a good agreement between molecular and pigment data. 16S rDNA sequences of plastids of eukaryotic algae also were retrieved, mostly related to those of an environmental clone called OM164, which has not been cultivated but has phylogenetic affinities to the Raphidophyceae. © 2002 Elsevier Science Ltd. All rights reserved.


Publication title

Deep-Sea Research Part II










Institute for Marine and Antarctic Studies


Pergamon-Elsevier Science Ltd

Place of publication


Repository Status

  • Restricted

Socio-economic Objectives

Assessment and management of terrestrial ecosystems

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