Changes in heavy metals (Fe, Mn, Zn, Cu, Cd and Pb) concentrations in marine seaweed (green alga) Ulva sp. and seawater collected from the the Mediterranean Coast, Alexandria region, Egypt were investigated during monthly samplings from January to December 2012 to assess the spatial and seasonal variation of these elements as well as the pollutional status at this area. Fe had the highest concentration and Cd found the lowest one. There were statistically positive significant correlations among the levels of some metals in the macroalgae. The mean metals concentration in
the Ulva tissue decreased in the order: Fe>Mn>Zn>Cu>Pb>Cd. Only, concentrations, Fe, Zn and Pb, in water showed significant (P<0.05) seasonal changes. Fe, Mn, Zn and Cu showed the greater spatial and temporal differences (P<0.05) in macroalgae tissues. The results showed that the studied area not faced heavy metals pollution. It is
also concluded that Ulva sp. play an important role as a bioindicator for heavy metals contamination in seawater.