MAP Technical Reports Series No. 106 UNEP

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Some of the coastal lagoons in the Languedoc-Rossignol Region are also affected by
periodic events of eutrophication (Ménesguen, 1990). Lieutaud et al. (1991) attribute the gradual
trophic deterioration of eight lagoons along the shoreline of Montpellier (from the Or to the Ingril
lagoons) to the increased input of nutrients of urban and agricultural origin.
- Eastern zone between the Rhône delta and the Italian border. This zone receives the
effluents from large towns and cities (Marseilles, Toulons, Cannes and Nice) and from important
industrial areas (Region of Fos). There are generally no eutrophication phenomena in the open
sea waters because of the westward drift of oligotrophic waters carried by the Liguro-Provinçal
Current (Sournia et al., 1990). Events of algal blooms are mainly limited to ports and coastal
waters near the points of urban and industrial effluent discharges. The same applies to the Berre
and Vaine Lagoons, where Kim and Travers (1986) report high nutrient values and the
development of massive algal blooms. Bellan (1972) discusses the gradual deterioration of the
Berre and Vaine lagoon due to heavy pressure from the human population, which has caused
profound modifications in the animal and vegetable communities typical of these ecosystems.
Vitello and Keller (1991) reach the same conclusions from their studies on the meiobentos of
the Berre lagoon.
- Corsica. This island, with few lagoons (Diana and Urbino) and with a fairly high level of
hydrodynamism along its coasts, is only marginally affected by the urban effluents from the cities
of Bastia and Ajaccio, and by the small amounts of industrial effluents discharged.
Eutrophication phenomena are of little significance and very occasional off Corsica.
As to nuisance species it appears that the numbers of toxic flagellates present in
French seas have increased over time. Until 1982 only Gyrodinium aureolum was present, while
the Dinophysis species appeared in 1983 gradually becoming dominant. Alexandrium minutum
was reported for the first time in 1988 (Belin et al., 1989). Dinophysis is present off the South
coast of France, where it is thought to have made its first appearance in 1987 (Leveau et al.,
1989; Lassus et al., 1991).
Routine analyses performed in areas affected by the presence of toxic flagellates have
highlighted three important facts:
a) their presence cannot be correlated with and does not depend on the inputs of
nutrients resulting from human activities;
b) in the areas where these organisms are present there is no alteration at the level
of grazing due to inputs of pollutants (Leveau et al., 1989);
c) their presence even at low concentrations (a few individuals/litre) and in absence
of real blooms may be unsafe to human health.
It must be noted that anoxia in French coastal waters has never reached the levels of
the Skagerrat (Rosenberg, 1985) or the northern Adriatic (Rinaldi et al., 1993). Shortages of
oxygen in the waters near the sea-bed after algal blooms were reported in the Bay of Vilaine in
July 1984 (Marceron, 1987), but there were no serious consequences.
5.2.3 The Coasts of Italy
General. Manifestations of eutrophication occurring in the Italian seas depend on the
hydrology, hydrodynamics and morphology of the areas concerned. In the Ligurian Sea, the
Tyrrhenian Sea and the southern Adriatic, the phenomena are episodic and generally not