Mediterranean Sea
A Sea Between Continents
The Mediterranean is among the world’s smallest seas; three continents—Europe, Asia, and Africa—border its shores, and its waters connect with the Atlantic Ocean, the Black Sea, and the Red Sea. It is a global biodiversity hotspot, home to unique and precious ecosystems with a great variety of species—many of them endemic—making it a biogeographic region of extraordinary importance, yet one facing numerous pressures and threats.
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A long and complex history
The Mediterranean occupies a geodynamically complex region and is the remnant of the Tethys Ocean, a vast east–west tropical seaway that in the Jurassic separated two great continental blocks: Laurasia to the north and Gondwana to the south. Over subsequent geological eras, the convergence of the African and European plates, together with the opening of the Atlantic, drove the progressive closure of the Tethys. This led to the formation of two major marine basins—eastern and western—and to the rise of the mountain chains that still ring the Mediterranean today. Exceptions are the low-lying areas corresponding to coastal plains or river deltas, and the broad zone that extends from eastern Tunisia to the Sinai Peninsula.
Today the Mediterranean is a nearly landlocked basin and, although it contains less than 1% of the Earth’s ocean water, it hosts about 8% of known marine species. Its connections with the Atlantic, the Black Sea, and the Red Sea each contribute to a unique mix in which relict species—survivors from past geological eras—coexist with organisms typical of oceanic, temperate, and subtropical environments.
We thank Giovanni Chimienti and Tamara Lazic for their video contributions.
This section includes:
Posidonia, the Queen of the Mediterranean
6:19
These are true underwater forests, created by a plant that blooms and sets fruit beneath the surface, produces oxygen, shelters many other organisms, and protects coastlines.dall’erosione.
Endemic Species of the Mediterranean
9:28
About 30% of Mediterranean species are endemic—found only in this sea. Tourism, overfishing and illegal fishing, habitat degradation, and non-native (invasive) species are the main threats they face.
Non-native Species in the Mediterranean
8:26
Biological invasions are a major problem: organisms introduced—whether intentionally or accidentally—into a new environment are almost always a threat to native species.
Black Coral of the Mediterranean
8:33
