A potencialidade de Diatomáceas perifíticas como bioindicadoras de metais

Abstract

Diatoms are widely used tools in monitoring programs due to their ability to reflect environmental variation. Although many studies have employed this group of microalgae as bioindicators of nutrients, investigations addressing their use as bioindicators of metals remain scarce. This study aimed to evaluate the potential of diatoms as bioindicators of metals. To estimate species autoecology, ecological optima, tolerance ranges, and ecological sensitivity were calculated along gradients of Fe, Al, Mn, As, and Pb. Periphytic diatom samples were collected in lotic and lentic environments of the Doce River Basin, Espírito Santo, Brazil, allowing comparisons of species and community level responses to metal gradients between these habitat types. The influence of metals on community composition was habitat-dependent, with Al and As associated with variation in lotic environments and Fe, Al, Mn, As, and Pb in lentic environments. Autoecological analyses revealed sensitive and tolerant taxa, with patterns of ecological optima and tolerance varying among the assessed metals and between habitat types. Community sensitivity analyses indicated that for iron, positive responses predominated in lotic environments and negative responses in lentic environments, whereas aluminum showed the opposite pattern, with predominantly negative responses in lotic environments and positive responses in lentic environments. For Mn, As, and Pb, positive community responses predominated in both environments, indicating the predominance of tolerant taxa along the gradients. Overall, the results demonstrate that diatoms have high potential as bioindicators of metals, consistently reflecting variations in these contaminants.