The seabed and algae.
The seabed in front of Sottomarina is relatively shallow. This means that the energy of the sun’s rays can reach very abundant and promote the growth of a rich and varied ecosystem.
Going offshore Sottomarina, about eight kilometers away, just beyond the horizon line, there is a place with very special rock formations, unique in their kind: the coral reef that is called the le Tegnùe.
A very recent study has clarified how and when the le Tegnùe formed.
We must go back ten thousand years. In that remote time the last Ice Age was coming to an end and the sea level was much lower than it is today. In particular, the Adriatic Sea was already ending in Ancona, so the great rivers such as the Po and the Brenta had to travel a long road to get to the sea.
The gradual rise in temperature and the consequent melting of the ice made the sea level rise again and in the following two thousand years the Adriatic Sea rose up to the present shores.
The old riverbed, now submerged by the sea, had a special property with respect to the sandy seabed that has always been characteristic of this sea: it was a structure of sand and shells compact and cemented almost like a rock.
On this stable and robust base, numerous colonies of calcareous red algae developed.
Seven thousand years ago, the le Tegnùe coral reef was born.
This reef differs from the more known coral reefs because it is not formed by corals, but by calcareous red algae called coralligenous.
On this substratum of calcareous algae an ecosystem with a great variety of marine flora and fauna has come to life: fish, sponges, sea anemones, hedgehogs, stars and algae of many species. A unique environment, with a biological heritage of great value and interest.
So when you walk along the seafront in Sottomarina, you can see many different algae that testify to the richness of the living forms that populate the ecosystem of le Tegnùe.
Tradition has it that when fishermen threw their nets off Sottomarina, they often found themselves with torn nets.
The tale of a submerged Chioggia, of a legendary Adriatic Atlantis, of a ghost town under the sea, where the nets were retaint by the bell towers of the churches and by the chimneys of the houses, was thus spread. This legend and this myth have come down to us with the name le Tegnùe: “the retained”… It was the rocks of the coral reef that held back the fishermen’s nets!
It is true that the sea always remains a mystery and it is up to us to discover its secrets.
Sottomarina, 6 August 2018
Elisabetta Ghini, PhD in biology.
Roberto Ghini, PhD in Physics