Portofino Dive

THE MEDITERRANEAN

When observing the Mediterranean Sea from a satellite it appears like a single unit but, under an oceanographic point of view, it can be divided in Western Mediterranean and Eastern Mediterranean, which differ for the temperature and for the different degree of salinity. For example, in the western basin the temperatures vary from 12°C in winter to 23°C. In summer, it has a degree of salinity of 36 per thousand. Instead, the eastern basin has variable temperatures from 16°C in winter to 26-29°C in summer with a degree of salinity of 39 per thousand.

So the areas of the Catalonia Sea, of the Lion Gulf, of the Ligurian Sea and of the High Tyrrhenian Sea are characterised by atlantic/boreal influences with many species coming from the Atlantic and shortage of organisms typically Mediterranean. Anyway in these areas there are exceptions as in the case of the "Promontorio di Portofino" that, for the play of currents, for the nature and the composition of rocks, for the influence of the very mild climate is defined a xerothermic hot oasis. This permits the development of typical organisms of more meridional areas, which characterise the richness of the seabeds and of the sea of this area.

The Promontory of Portofino deep-water temperature is decidedly stable (13°C), while in the more superficial surfaces it is influenced by climate. At the end of winter and in spring the temperature of surface waters conforms to the one of the deep waters. Generally from July the temperature is around 24-25°C keeping this values till the beginning of the month of October. After that it goes down really gradually. In Ligury the climate is temperate, with not so hot summers and mild winters. The tide is inferior to 30 cm. and it is pratically imperceptible.

The ligurian coast extends for a legth of approximately 350-km. between the French frontier and the mouth of river Magra; it develops with the form of a big arch with the Gulf of Genoa in its centre.

The structure of the ligurian coast has its natural prosecution in the seabed configuration. In fact the coast is less hard in the West-Ponente (where there are wide sandy beaches) and more steep in the East-Levante, where the cliff go down into the sea with coves which open in frequent promontories.