Electron microscopy technique was used to study the copper induced ultrastructural changes in the
blue green alga, Synechocyslis salina. Wislouch and golden yellow flagellate /sochrysis ga/bana Parke. The
blue green alga exhibited significant deterioration in the cell's internal organisation. Presence of membrane
whorls. disorganisation of cell envelop. Photosynthetic lamelleae at certain regions of the cell, reduction in
cellsize increase in number of polyhedral bodies and absence of lipid inclusion was observed. Drastic
change was not noticed in the golden yellow flagellate except for the presence of enlarged vacuoles and
more number of osmophilic bodies. Toxicity and detoxification mechanisms are discussed and the utili zation
of electron microscopic analysis is established in the studies of metal toxioity at the cellular leve
