Trace metal concentrations in marine macroalgae from different biotopes inthe Aegean Sea

The commonest species of red, brown, and green macroalgae were sampled from a range of biotopes in the Aegean Sea and analysed for five different trac e metals. Significant differences in metal concentrations were found among different seaweed species from the same biotope. The concentrations of meta ls in the various seaweed species may reflect their morphology, with those having a larger surface area having a greater internal content. Different s pecies of seaweed have different affinities for different heavy metals. Thi s may reflect competition between metals for binding or uptake sites in the seaweed. Comparing metal concentrations in algae among the studied samplin g stations clearly indicates that the degree of accumulation depends not on ly on human activities but also on the geology of the specific area. While seaweed can be used successfully to assess the levels of heavy metals in th e marine environment, not all elevated concentrations of heavy metals neces sarily reflect increased levels of pollution. Indeed, the high concentratio ns of certain metals, e.g., Ni, found in our seaweed samples reflected the metaliferrous nature of the rock. It is therefore important to take account of a region's geology before attempting to interpret the data. (C) 2001 El sevier Science Ltd. All rights reserved.