In evaluating the effect of CCA leachate on the establishment of fouling communities on wood exposed in the sea, three organisms were assessed as biological indicators of heavy metal toxicity. These were two macroalgae, Fucus serratus and Undaria pinnatifida. and the motile protist thraustochytrid, Schizochytrium aggregatum. The choice of these organisms for the tests carried out was based on the need for rapid methodology and relative simplicity in their isolation and cultivation. The two test algae were collected locally on the south coast of England, cleaned of surface contamination and prepared for release of their respective reproductive spore types. Toxic effects of a range of concentrations of CCA leachate were then measured in terms of spore/zygote germination using simple microscopic observations after 3-4 days incubation. The thraustochytrid was obtained from stock cultures held at the University of Portsmouth. The zoosporic stage in the life cycle of this organism was used to indicate the toxic effects of copper ions in seawater-based medium by measuring loss in motility over a 20 minute period. Data were collected using motion analysis equipment. Subsequent recovery of zoospores after 1 hour exposure to different copper levels was determined. Non-motile stages of the life cycle of thraustochytrid isolates were also used to determine copper toxicity. Tolerance of these organisms to heavy metals in CCA leachates will be discussed.

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