Sea of Marmara

The Sea of Marmara is a unique inland sea located entirely within Turkey.

It serves as a vital maritime link between the Black Sea and the Aegean Sea. This connection is made through two narrow waterways known as straits. The Bosporus connects the sea to the Black Sea in the northeast. The Dardanelles connects the sea to the Aegean Sea in the west. Because of its position, the sea also separates the European and Asian sides of Turkey. It is often considered the smallest sea in the world.

The hydrology, or the study of how water moves, of the Sea of Marmara is quite complex. The surface salinity, which is the amount of salt in the water, averages about 22 parts per thousand. This level is slightly higher than the Black Sea. However, it is only about two-thirds as salty as most of the world's oceans. The water becomes much more saline at the bottom of the sea. The bottom water averages around 38 parts per thousand. This concentration is similar to the salt levels found in the Mediterranean Sea. This high-density saline water stays at the bottom and does not migrate to the surface.

Several rivers contribute to the water system of this sea. The Susurluk, Biga (also called the Granicus), and Gönen rivers all flow into the Sea of Marmara. These rivers help to reduce the overall salinity of the water. Most of these rivers flow from Anatolia because there is very little land in Thrace that drains southward. The sea's coastline is also defined by several large indentations. These are known as gulfs. The south coast includes the Gulf of İzmit, the Gulf of Gemlik, the Gulf of Bandırma, and the Gulf of Erdek.

The history of the region is reflected in its ancient names and myths. In classical antiquity, the Greeks called the sea the Propontis. This name comes from the Greek words meaning "in front of" the Black Sea. This was because Greek sailors traveled through these waters to reach the Black Sea. Greek mythology also features the Propontis. Legend says a storm on these waters brought the Argonauts back to an island. This event led to a battle involving the heroes Jason or Heracles. The sea's modern name comes from Marmara Island. This island is located on the south side and is named for its rich marble deposits.

There are two main groups of islands within the Sea of Marmara. The first group is the Princes' Islands in the north. This archipelago includes inhabited islands such as Kınaliada, Burgazada, Heybeliada, Büyükada, and Sedef Adası. These islands are part of the larger urban area and are easy to reach by ferry from Istanbul. The second group is the Marmara Islands in the south. This group includes Marmara Island, Avşa, Paşalimanı, and Ekinlik. It also contains seventeen mostly uninhabited islands. One of these is the island of Imralı. During the summer, many tourists travel to these islands by ferry from Istanbul.

Despite its small size, the Sea of Marmara is incredibly important for the population of Turkey. About one-third of the country's total population lives in the basin surrounding the sea. Major cities like Istanbul are located along its coasts. This high population density brings significant environmental challenges. Rapid population growth and uncontrolled construction have put heavy pressure on the marine environment. For many years, waste was dumped into the sea without much treatment. This caused many species to disappear. In the "East Bay," pollution was so severe that fishing was banned for years.

Natural and human-made disasters also affect the area. The North Anatolian Fault runs directly under the sea. This fault line has caused major earthquakes, including the Izmit and Düzce quakes in 1999. The August 1999 event is often called the Marmara Earthquake because its epicentre was under the sea. In December 1999, a Russian oil tanker broke in two during a storm. This accident spilled more than 1,500 tonnes of oil into the water. Another recent problem was the appearance of mucilage. This is a thick, sticky substance that appeared in early 2021. It lasted for six months and caused habitat loss and economic issues for fishing.