MAP Technical Reports Series No. 106 UNEP

Sardinia
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In general, the coastal waters and lagoons of Sardinia seem to be little affected by
eutrophication. The few reports concern the Gulf of Olbia, the Gulf of Cagliari and the Santa
Giusta Lagoon (Oristano).
For the Gulf of Olbia Sechi et al. (1987) report a bloom of Gymnodinium sp. which
occurred in September 1985. This event caused kills of fish and molluscs as a result of
prolonged anoxia of the bottom waters. The trigger causes are attributed above all to the
discharge of sewage from the town of Olbia. States of anoxia leading to fish kills have also
occurred in the Lagoon of Santa Giusta (central-western Sardinia); in a study conducted during
1989-93 by Cossu et al. (in press) the phenomenon is associated to the abnormal growth of
microalgae (Ulvaceae) and diatoms caused by high eutrophying inputs of urban origin.
In the Gulf of Cagliari, Loi et al. (1981) found high nutrient concentrations in the coastal
area most affected by urban and industrial effluents. For the same gulf, Genovese (1979) also
reports high primary productivity values (446 mg C/m 2 /day) in the presence of Rhizosolenia
firma.
Sicily
Northern shores. Frequent blooms of Chlamydomonadaceae are reported (De
Domenico, 1979) for in the Bay of Milazzo, but their development is probably not correlated with
the inputs of nutrients. In the adjoining Gulf of Patti (Messina), in July 1969 Gangemi (1973)
detected blooms of the same microalgae after heavy rains.
Also in the province of Messina, cases of eutrophication were reported in the brine
Lakes of Ganzirri (Magazzu' et al., 1991) and Faro (Magazzu', 1982) that lay in basins of high
human activity. Large numbers of fish died in the Lake of Ganzirri in 1990 as a result of anoxia.
Dinophysis sacculus (a toxic species capable of synthesizing DSP group toxins) reaching
40,000 cells/l have been reported in other brine lakes (Olivieri and Tindari) in the same area.
More or less frequent algal blooms occur in coastal waters of the Gulf of Palermo
summer (Genchi et al., 1983a; 1983b). Due to discharges of inadequately treated sewage high
values of nutrients and chlorophyll-a were found above all in the area off and to the East of the
port of Palermo (for the area near the port: 25 mg-at/m 3 of ammoniacal nitrogen, 158 of nitric
nitrogen, 360 of orthophosphate and 30 mg/m 3 of chlorophyll-a in March 1981). Coastal waters
are also affected by a high bacterial pollution.
The Gulf of Castellammare also shows recurrent cases of eutrophication caused by
the excessive inputs of nutrients from sewage and industrial effluents (Calvo and Genchi, 1989);
total input of 321 tons/year of phosphorus and 1,471 of nitrogen, 195 and 685 of these
respectively of industrial origin have been estimated.
Riggio et al. (1992) report an interesting succession of biological indicators in the same
area. As a consequence of increased eutrophication the bivalve Mytilaster minimum, which
favours oligotrophic-eutrophic environments, was partially supplanted by Mytilus galloprovincialis
that grows better in eutrophic-hypertrophic conditions.