Analysis of phytoplankton of the Australian sector of the Southern Ocean: comparisons of microscopy and size frequency data with interpretations of pigment HPLC data using the 'CHEMTAX' matrix factorisation program

A new matrix factorization program 'CHEMTAX' was used to interpret high-performance liquid chromatography (HPLC) pigment data from a transect between Prydz Bay, Antarctica, and Australia during March 1987. The program calculated the abundance of diatoms, dinoflagellates, haptophytes resembling Emiliania huxleyi, haptophytes resembling Phaeocystis antarctica, cyanobacteria, prasinophytes, chlorophytes and cryptophytes along the transect. The results were compared with those of microscopy and particle size analysis. The transect was dominated by small cells: particle size analysis showed that particles 20 μm never represented more than 3% by number but constituted 57 to 93 % of the total volume. Microscopic analysis showed that small flagellates were the most abundant cells along the transect, with a 5-fold increase in abundance at 47°S. Numbers of diatoms (most