Mediterranean Sea

The Mediterranean Sea is a large body of water between Europe, Asia, and Africa. It is almost completely surrounded by land, connecting to the Atlantic Ocean through the narrow Strait of Gibraltar and to the Black Sea through the Bosporus. It also links to the Red Sea through the Suez Canal. Covering about 2.5 million square kilometres, the Mediterranean includes many smaller seas such as the Aegean, Adriatic, Tyrrhenian, and Marmara.

This area has been very important throughout history. Many early civilizations, like those in Egypt, Greece, and the Fertile Crescent, developed here. The sea served as a major trade route, helping people share ideas, goods, and cultures. The Roman Empire once controlled all the lands around the Mediterranean.

The Mediterranean has an average depth of about 1,500 metres, with its deepest point reaching over 5,000 metres in the Calypso Deep. Its climate is mild, with warm summers and cooler, wetter winters. Many countries, including Spain, France, Italy, Greece, Turkey, Egypt, and Morocco, have coastlines along its shores. The sea also includes many islands, the largest being Sicily and Sardinia.

Names and etymology

The Mediterranean Sea has had many names throughout history. The Romans called it Mare Magnum ("Great Sea") or Mare Nostrum ("Our Sea"). The term Mare Mediterrāneum means 'in the middle of land, inland' in Latin.

In Modern Arabic, it is known as al-Baḥr [al-Abyaḍ] al-Mutawassiṭ, 'the [White] Middle Sea'. The Ancient Egyptians called it Wadj-wr/Wadj-Wer/Wadj-Ur, meaning 'great green'. The Ancient Greeks often simply called it ἡ θάλασσα ('the Sea').

Different cultures gave the sea various names based on their geography and history. The Ancient Iranians called it the "Roman Sea", while in Turkish it is known as Akdeniz, meaning 'the White Sea'.

History

Main article: History of the Mediterranean region

Major ancient civilizations lived around the Mediterranean Sea. The sea helped people trade, move to new places, and fight. It also gave food from fishing to many communities. Some of the earliest advanced civilizations were the Egyptians and the Minoans, who traded a lot with each other. Later, the Greek city-states and the Phoenicians also used the sea for trade and settling new areas.

After the Punic Wars, the Roman Republic became very powerful in the Western Mediterranean. The Romans called the sea Mare Nostrum, meaning "Our Sea," because they controlled almost all of it for many years.

During the Middle Ages, new powers like the Byzantine Empire and later the Arabs influenced the area. They brought new foods like sugarcane, rice, and oranges to places such as Spain and Sicily. Trade continued between Europe and Asia, even though there were wars and changes in power.

In more recent times, the Mediterranean has been important for trade and travel. The opening of the Suez Canal in 1869 changed trade routes, making the Mediterranean very busy. In the 20th century, wars like World War I and World War II affected the sea and its nearby lands.

In the 21st century, the Mediterranean has seen many people trying to cross from Africa to Europe. Sadly, some boats have sunk, and many people have not survived the journey. Europe has tried different ways to help and protect those traveling across the sea.

Geography

Main article: List of islands in the Mediterranean Sea

A satellite image shows the Mediterranean Sea. The Strait of Gibraltar appears in the bottom left, separating the Iberian Peninsula in Europe from Morocco in Africa.

The Dardanelles strait in Turkey separates parts of Europe and Asia.

The Mediterranean Sea connects to the Atlantic Ocean by the Strait of Gibraltar, which also separates Europe from Africa. It connects to the Sea of Marmara and the Black Sea by the Straits of the Dardanelles and the Bosporus, separating Europe from Asia. The Suez Canal links it to the Red Sea.

The coastline of the Mediterranean is about 46,000 km long.

The Mediterranean Sea includes 15 smaller seas. It stretches from the Strait of Gibraltar in the west to the Dardanelles and the Suez Canal in the east, bounded by Europe, Africa, and Asia. It is divided into two deep basins.

The basin of the Mediterranean includes many rivers, with the Nile being the longest. Important rivers also include the Rhône, Ebro, Po, and Maritsa.

Countries with coastlines on the Mediterranean Sea include Spain, France, Italy, Malta, Monaco, Slovenia, Croatia, Bosnia and Herzegovina, Montenegro, Albania, and Greece in Europe; Turkey, Syria, Lebanon, Israel, Palestine, and Cyprus in the Middle East; and Morocco, Algeria, Tunisia, Libya, and Egypt in North Africa.

The International Hydrographic Organization divides the Mediterranean into smaller water bodies, including the Strait of Gibraltar, Alboran Sea, Balearic Sea, Ligurian Sea, Tyrrhenian Sea, Ionian Sea, Adriatic Sea, and Aegean Sea.

The Mediterranean has about 10,000 islands and islets, with around 250 that are permanently inhabited.

Much of the Mediterranean coast has a climate with mild, wet winters and hot, dry summers. Though rare, tropical cyclones can sometimes form in the sea during September to November.

Seabed

The Mediterranean Sea has many interesting underwater features shaped by the movement of Earth's plates. The African Plate moves under the Eurasian Plate, creating natural divisions in the sea. The Malta Escarpment separates the western and eastern parts, stretching from Sicily to the Maltese islands.

The western Mediterranean includes three main underwater areas. The Alboran Basin lies between Morocco and Spain. The Algerian Basin stretches from Algeria to France and has deep parts reaching nearly 3,000 metres. The Tyrrhenian Basin is between Italy and the islands of Sardinia and Corsica, featuring large underwater volcanoes.

The eastern Mediterranean also has several underwater basins. The Ionian Basin, south of Italy, Albania, and Greece, holds the deepest point in the sea. The Levantine Basin lies south of Anatolia and includes special underwater ridges and structures. The Aegean Sea is north of Crete, bordered by Turkey and Greece, with many islands and underwater peaks. The Adriatic Sea is northwest of the main body, bordered by countries like Italy, Slovenia, and Croatia.

The Malta Escarpment is a long underwater cliff formed by tectonic forces, stretching from Sicily to Malta. It features deep valleys and rich marine life, studied by scientists from several countries.

Oceanography

Evaporation in the Mediterranean Sea is much higher than rainfall or water flowing into it from rivers. This causes the water level to drop and the water to become saltier, especially in the eastern part of the sea. The average amount of salt in the water is about 38 PSU.

The water in the deepest parts of the Mediterranean is quite cold, around 13.2 °C. The sea gets its water mainly from the Atlantic Ocean through the Strait of Gibraltar. Without this water, the sea level would drop by about 1 meter each year.

Water moves around the Mediterranean in a pattern. Cool water from the Atlantic flows in and moves eastward along the northern African coast. Some of this water turns north towards Corsica before leaving the sea. In the eastern part, the water warms up and becomes saltier, making it heavier. This heavier water sinks and forms a layer called Levantine Intermediate Waters (LIW). These waters move west along the coasts of Greece and southern Italy. After passing through the Strait of Sicily, they flow along the coasts of Italy, France, and Spain before leaving through the Strait of Gibraltar.

Deep water in the Mediterranean comes from three main places: the Adriatic Sea, the Aegean Sea, and the Gulf of Lion. Strong winter winds cause very cold water to sink, creating new deep water. This mixing of old and new water takes about 100 years. Because of this, changes in climate can greatly affect the Mediterranean.

The Mediterranean is very sensitive to climate change. Since the 1950s, temperatures in the sea have been rising. Climate change is expected to cause less rain, more evaporation, and higher salinity. This can make the water layers separate more clearly, affecting how water moves and the chemistry of the sea. Warmer temperatures can also cause harm to sea life, leading to loss of some species and allowing others, usually found in warmer areas, to move in. These changes can greatly impact the balance of life in the Mediterranean.

Biogeochemistry

The Mediterranean Sea has a lot of different kinds of plants and animals, but it also has very little food for them. This makes it a place where it's hard for plants and animals to grow well.

The sea has places where there is more food than others. Near the coast and where rivers flow into the sea, there is more food for plants to grow. In the winter, strong winds and rain mix the water and bring up more food for tiny plants called phytoplankton. But in the summer, the water gets warm and stays on the top, so there is less food. Most of the plants in the sea grow not on the surface, but a little deeper down. The sea also has more of one kind of food compared to another, which affects what kinds of tiny plants and animals can live there.

Geology

See also: Geology and paleoclimatology of the Mediterranean Basin

The geologic history of the Mediterranean Sea is very interesting. It used to be thought that the sea was part of an ancient ocean called the Tethys Ocean, but we now know it is a younger basin called the Neotethys. This younger basin formed when the African Plate and Eurasian Plate moved together during the Late Triassic and Early Jurassic.

Because the Mediterranean is almost surrounded by land and has a dry climate, it loses a lot of water through evaporation. This led to a big event called the Messinian salinity crisis, when the sea became landlocked and almost dried up about six million years ago. There are thick layers of salt on the bottom of the sea from that time.

The sea was filled again about 5.3 million years ago in a huge flood called the Zanclean flood. Water rushed in from the Atlantic Ocean through the Strait of Gibraltar very quickly.

The Mediterranean Sea is not very deep on average, but its deepest point, the Calypso Deep in the Ionian Sea, is over 5,000 meters deep. The coastline of the Mediterranean is very long, stretching for about 46,000 kilometers. There is a shallow area between the island of Sicily and the coast of Tunisia that splits the sea into two parts: the Western Mediterranean and the Eastern Mediterranean.

Messinian salinity crisis

During times when the land moved, the ways that connected the Mediterranean to the Atlantic Ocean gradually closed. This happened several times, and one of these closures led to the Messinian salinity crisis. The sea level dropped a lot, and huge amounts of salt built up.

This crisis started about 5.96 million years ago and lasted for around 630,000 years. It ended when the Atlantic Ocean filled the basin again through the Strait of Gibraltar, in an event called the Zanclean flood.

Desiccation and exchanges of flora and fauna

See also: Pleistocene megafauna and Dwarf elephant

The way the Mediterranean connects to the Atlantic Ocean changed over time. Earlier connections closed, which also caused drops in sea level. These events allowed plants and animals to move between Africa and Europe. Many large animals, including some early relatives of humans, were able to travel between the continents.

Today, the Mediterranean loses more water through evaporation than it gains from rain and rivers. This makes the water in the Mediterranean saltier than the Atlantic Ocean. The saltier water from the Mediterranean flows under the less salty water from the Atlantic Ocean when they meet at the Strait of Gibraltar.

Paleoclimate

The Mediterranean Sea is very sensitive to changes in the Earth's climate because of where it is located and how it is surrounded by land. Scientists study layers of mud and dirt that settle in the sea to learn about past climates. These layers show whether the area was dry or wet at different times, helping us understand what the weather was like millions of years ago. This information also helps us figure out when the Earth's magnetic field changed direction in the past.

Biodiversity

The Mediterranean Sea has a rich variety of plant and animal life. Because its currents flow in a way that keeps the water stable, it creates a good home for many different kinds of sea creatures. Scientists believe there are over 17,000 types of marine life in the Mediterranean, especially near the shorelines.

Most of the sea's plants and animals originally came from the Atlantic Ocean. Over millions of years, they have adapted to the warmer, less nutrient-rich waters of the Mediterranean. The Alboran Sea, where the Mediterranean meets the Atlantic, has a mix of species from both areas. One special resident is the Mediterranean monk seal, found in the Aegean Sea in Greece.

While there used to be a group of orcas living in the Mediterranean, they are no longer found there today.

See also: Specially Protected Areas of Mediterranean Importance, List of fishes of the Mediterranean Sea, and List of fishes of the Black Sea

Environmental issues

For thousands of years, people have changed the land around the Mediterranean Sea. This has made the area look very different from long ago. Some people thought the land was once a perfect paradise but was ruined by people. However, this is not true. The land has always been changing in many ways.

The weather and plants in this area have gone through many changes over time. Some trees were cut down even before the time of the Romans. Big farms changed the land a lot, but then many people left when the Roman Empire ended. Today, many forests are gone, and the weather keeps changing. The sea and land here are always moving and shifting.

In recent years, more people have built homes and towns along the coasts. This has hurt the natural habitats and made the land less varied. Many traditional ways of farming have stopped, which also changes the landscape.

The Mediterranean Sea is a place where the earth’s plates push and pull together. This makes the area prone to earthquakes, big waves called tsunamis, and underwater landslides. These can be very dangerous for people living near the coast. Climate change is also making storms and flooding worse, putting more people at risk.

Many new plants and animals have come to the Mediterranean Sea from far away, especially through a man-made waterway called the Suez Canal. These newcomers compete with the native plants and animals, sometimes pushing them out. This change can harm the natural balance of the sea.

As the world warms up, the Mediterranean Sea is expected to rise in level. This could flood some coastal areas and islands, making it harder for people and animals to live there. Wetlands and special places for animals could also be lost.

The Mediterranean Sea has a lot of pollution. Many things like sewage, oil, and chemicals are poured into the water every year. This hurts the fish and other sea life. One type of sea mammal, the Mediterranean monk seal, is in big trouble because of all the pollution.

Many ships travel through the Mediterranean Sea, carrying lots of oil. Sometimes accidents happen, and oil spills can damage the water and the creatures that live there.

The beaches and coastlines of the Mediterranean have always been popular places for people to visit. Today, millions of tourists come every year. This brings money to many places but can also hurt the environment. Too many buildings and too many visitors can damage the beaches, the water, and the homes of animals like sea turtles and seals.

There is not enough fish in the Mediterranean Sea. Many fish populations are very low because people have been catching too many fish for too long. Big, older fish are disappearing, and the fish that are left are smaller and not as healthy.

The warm waters of the Mediterranean are getting even warmer because of climate change. This has caused many sea animals to die off for several years in a row, changing the sea’s life dramatically.