Abstract

A major threat to the seagrass ecosystem worldwide, due to the growth of human population along the coastal environment, is pollution or contamination resulting from industrial and urban development. Although seagrass appears to be rather resistant to heavy metal contaminants, these substances may possibly harm some components of the seagrass and such responses have not been examined to a significant extent.  Lead (Pb) and copper (Cu) was tested on seagrass, Halophila ovalis, to see whether the metals areenvironmental stressor on the seagrass. Reduced growth rate of the seagrass was observed both in Pb and Cu treatments. Leaf size of the plant also reduced as the metal concentrations increased and when the plants were exposed to the heavy metal for longer duration. An increased leaf asymmetry was more apparent at the 2 mg/L Cu treatment and no significant increases in fluctuating asymmetry were found in Pb treatment or in low levels of Cu treatment. Further discussion were made in view of selecting non-costly bioindicators of heavy metal contamination.

Key words:  Bioindicators, fluctuating asymmetry, Halophila ovalis, heavy metals, seagrass.