Coastal landscape

The coast is a strip of soil between the mainland and the sea. The coast is constantly shaped by the action of the sea (waves and tides), the wind and atmospheric agents. We do not have to forget that some organisms, such as corals and algae, can destroy or build a part of the coastal landscape. Coasts can be low or high, rocky or sandy. High and rocky coasts are characterized by steep cliffs whose base is excavated by the waves. This can favour the collapse of the higher walls and therefore the withdrawal of the coast. Typically, this landscape is characterized by bays and creeks that facilitate the construction of ports. The most typical shape of low coasts is a beach, made up of stones in the most internal part and sand that becomes finer and finer towards the sea. The waves and the material that is deposited on a river mouth manage to constantly pile up debris close to the coast, by forming borders, barriers, banks and shores.
The different types of coast are:

  • high coasts with cliffs: they are characterized by a vertical rocky slope straight on the sea (ie. Coasts of Normandy, English coasts on the English Channel, coasts of Scotland and Ireland). At the bottom of the walls the waves carve some deep cracks that form spectacular shapes like arches, rocks and caves.  The cracks can be quite deep and provoke the collapse of the rocky wall. In this way the cliff wall withdraws. Coasts are not only shaped by the action of the sea, but they are also shaped by tectonic movements of the Earth’s crust and by sea movements.  In fact, we can find some sea caves that are now located tens of metres above the current sea level, while others are completely submerged. Examples are the sea caves of Circeo, of the channel of Otranto, Capo Palinuro, Capri, Sardinia and Liguria;
  • rias coasts: they originated as a consequence of the sea invading old river valleys. The heights form peninsula and capes. Examples are Galicia, western Corsica, central-southern Greece. Deep gulfs and creeks that host ports are typical of this type of landscape. Old valleys that were occupied by glaciers and that are now invaded by the sea have formed the fjords, while the skjars (rocks garden) are coasts formed of several small islands and rocks. They are typical of Finland and Sweden;
  • low coasts: they form when the destructive action of the sea is weaker and the river material settles. This material is distributed along the coast by weak sea currents and deposited on shallow waters, in areas that are protected by promontories. Waves move these deposits by forming long submerged piles that gradually emerge from the sea surface in order to form sandbanks and the typical beaches with a tongue or arrow shape that extend from the promontories.  These beaches can stretch more and set the borders of the bay, forming a lagoon. The evolution of the lagoon into a coastal lake occurs when there is a complete separation from the sea (Lakes of Lesina and Varano in Puglia region). Tombolos are created when sand strips connect the island with the mainland (Argentario mountain and Orbetello ponds). Beaches are a typical deposit of low coasts.

Lagoons
A lagoon is a stretch of sea, often some kilometres wide, with shallow waters and a low and sandy coast. The lagoon can be connected to the open sea by canals that facilitate water exchange and the lagoon cleaning. Usually, with time passing, the canals close and form coastal lakes. These small lakes are gradually filled with river material. Among the most famous lagoons in the world is the lagoon of Venice, located between the Po delta and Piave mouth.

 

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