Inter-Research
Marine Ecology Progress Series

ABSTRACT: Concentrations of Cd, Cu, Fe, Pb and Zn were measured in scales of the seagrass Posidonia oceanica from different areas of the French NW Mediterranean: the Côte d'Azur and Corsica.Scales are basal parts of the seagrass which remain fixed on the rhizomes when leaves of P. oceanica die. Scales do not decay and the cyclic variation of their thickness permits retroactive dating (lepidochronology). Heavy metal concentrations were determined in the scales of P. oceanica dated by lepidochronology. Scales from P. oceanica collected from the Côte d'Azur (analysis of lepidochronological years from 1982 to 1992) generally showed concentrations of Cu, Fe, Pb and Zn to be greater than those measured in samples from Corsica (analysis of lepidochronological years from 1972 to 1992). In contrast, Cd concentrations recorded in scales from Corsica were higher than in those from Côte d'Azur. The reasons for these high Cd values are unknown. There was a general tendency for metal concentrations in P. oceanica scales collected on the Côte d'Azur to decrease with time. In Villefranche-sur-Mer, where there are many pleasure boats, large concentrations of Cu were found in P. oceanica scales. These concentrations had increased in recent years.

KEY WORDS: Trace metals . Posidonia oceanica . Lepidochronology . Mediterranean

Published in MEPS Vol. 120 (1995) on April 20
Print ISSN: 0171-8630; Online ISSN: 1616-1599. Copyright © Inter-Research, Oldendorf/Luhe, 1995