MORPHOLOGICAL AND BIOCHEMICAL VARIABILITY OF THE TOXIC DINOFLAGELLATEPROROCENTRUM-LIMA ISOLATED FROM 3 LOCATIONS AT HERON-ISLAND, AUSTRALIA

Seventeen clones of the toxic, epiphytic-benthic dinoflagellate Proroc entrum lima (Ehrenberg) Dodge isolated from three separate sites on th e reef flats of Heron Island, Australia, were acclimated under the sam e set of environmental conditions. Morphological features examined for each clone included cell surface configuration, size, and dry weighs. Physiological and biochemical features determined for each clone incl uded reproduction rates, pigments (chlorophyll a, chlorophyll c(2), pe ridinin, and other xanthophylls), toxins (okadaic acid and methyl-okad aic acid), and macromolecular compounds (total protein, lipid, and car bohydrate). Variation in morphological features and reproduction rates of clones within and between sites was minimal and not significant. A lso, variation in biochemical features within an individual site was l ow, but pronounced differences existed among sites, the most notable o f which was toxin content (okadaic acid and methyl-okadaic acid). The greatest difference in biochemical features was between clones isolate d from the southern site and clones isolated from the northern and sou theastern sites. Results of a cluster analysis of clonal characters su pport the view that these two groups represent distinct genotypes. We suggest that these groups originated from separate seed sources and th at the genetic integrity of each is maintained through asexual reprodu ction.