NATURAL CONCENTRATION OF GERMANIUM IN THE GILL CELL-NUCLEI AND LYSOSOMES OF THE OYSTER CRASSOSTREA-GIGAS THUNBERG (MOLLUSCA, BIVALVE)

A systematic search for germanium was undertaken on oyster gills. Moll uscs were collected at different times of the year in seven different areas in the Channel and the Atlantic Ocean. Some of these areas are p rotected; others may be polluted by industrial wastes. Oyster cells ne ver present any signs of damage at the ultrastructural level. Lysosome s have heterogeneous densities and frequently contain germanium, detec ted by electron probe microanalysis. Nuclei, which are classical in as pect, may contain germanium, especially in the dense chromatin and nuc leolus. Irrespective of period and locality, the amounts of the detect ed element are of the same order. It seems unlikely that germanium ori ginates from pollution of the marine environment or contamination of t he samples. The physiological role of germanium is at present unknown. The bioaccumulation observed could nevertheless be the result of a no rmal physiological process involving nucleic metals.