The role of bacteria in the metal tolerance of the fouling diatom Amphora coffeaeformis Ag.

Components of “spent” axenic and non-axenic Amphora coffeaeformis Ag. culture media were tested for their effect on copper and tributyltin tolerance in axenic A. coffeaeformis. Growth of such algal cultures in the presence of either toxin was enhanced by the addition of enriched “spent” medium from exponentially growing non-axenic cultures. This response was seen whether or not the bacteria had been removed. It appears that bacteria or bacteria-algal interactions produce some soluble (<0.2 μm) factor which either decreases the toxicity of copper and tributyltinfluoride (TBTF) or increases the tolerance of A. coffeaeformis to these toxins.