The aims of the present work were to determine the concentration and localization of metals in algae living in a highly acidic, metal-rich pond and to assess the effect of excess metals in limiting the algae's access to essential mineral nutrients. Quantitative EDS studies revealed large species-specific differences in metal accumulation between the examined groups of algae, with the diatoms being comparatively enriched in Si and Al, and the chlorococcal forms containing unusually high concentrations of Fe. Si was found to co-accumulate with Al and Fe at the extracellular matrix of the algae, supporting its proposed role in alleviating metal toxicity. Phosphorus deficiency was not observed in any of the studied species, in spite of the high levels of Fe and Al in the acidic medium.