An analysis was made of the levels of Fe, Cu, Zn, Cd, Pb, Na, K, Ca an
d Mg in three green and four brown seaweeds, abundant in the Antikyra
Gulf (Viotia, Greece). After Ca and the macroelements K, Mg, Na, the h
igher concentrations found were of Fe and Pb, with Fe>Pb. Cadmium cont
ent was low in most species. Differences between species and taxonomic
groups were also considered. Fe, Zn, Cd and Ca in the green alga Dasy
cladus vermicularis increased from March to July and had their maxima
in summer or autumn (Cd), whereas Cu, Pb and Mg showed an opposite pat
tern of seasonal variation with maxima in winter. Cu, Zn, Cd and K in
D. vermicularis were correlated with their concentrations in the sedim
ent and not with their dissolved levels in seawater. Iron in D. vermic
ularis was positively correlated with Zn and negatively with Cd.