| Summary: | Summary. Vertical net haul diatom assemblages from near South Georgia, and from between Africa and Ant-arctica, were examined and compared. Variation among South Georgia stations was examined by principal com-ponent, cluster and canonical discriminant analyses. Dia-tom distributions provide evidence for at least two dis-tinct water masses. The region north of the island is char-acterized by neritic, temperate diatoms and by an assem-blage with low species diversity. The region south of the island is characterized by oceanic, antarctic species and relatively high species diversity. The regions are most dis-tinct to the west of the island, intergrading east of the is-land. Within the north-south division, five station group-ings were detected on the basis of distribution of domi-nant net diatoms. By comparing classical species ecologi-cal categorizations to results of principal component analysis, a "neritic-oceanic " factor was identified from net diatom distributions. This factor was common to both areas in spite of the fact that Biscoe and Agulhas collections were from different seasons.
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