The Baltic Sea

The Baltic Sea is considered an inland sea because it is almost completely surrounded by land. Denmark, Sweden, Finland, Russia, Estonia, Latvia, Lithuania, Poland and Germany lie around the Baltic Sea. These countries have been connected by the Baltic Sea for centuries.

There are connections between the North Sea and the Baltic Sea:

• the Little Belt between mainland Denmark and the island of Funen,
• the Great Belt between the islands of Funen and Zealand,
• as well as the Øresund between Zealand and the Swedish mainland.

The Kattegat, a sea area between Denmark and Sweden, provides a direct connection to the North Sea.

The Baltic Sea formed only after the last Ice Age, around 10,000 to 12,000 years ago. During the Ice Ages, northern Europe was covered by an ice sheet up to 3,000 m thick. When the ice melted, the water collected and eventually a new sea formed.

The Baltic Sea is up to 459 m deep. It covers about 413,000 square kilometres—an area roughly the size of Germany and Switzerland combined. The name “Baltic Sea” is used mainly in countries that border it. In English and other languages, it is also known as the “Baltic Sea.”

The Baltic Sea originally contained only fresh water. Fresh water also flows in our streams and rivers and contains only very small amounts of salt. Seawater, on the other hand, is much saltier and is not fit for human consumption.

The Baltic Sea’s salinity only increased when it mixed with water from the North Sea. It is still much lower than in the North Sea. Water of this kind is called brackish water. The straits between Denmark and Sweden are so narrow that only a little salt water can flow from the North Sea into the Baltic Sea.

The large rivers also provide a constant supply of fresh water. The water is also quite cold, so very little of it evaporates. This too helps keep the salt content low, and the water freezes relatively quickly in winter.

You can also observe the tides on the Baltic Sea. But the difference between high and low tide is rarely more than 15 to 30 centimeters, whereas on the North Sea it reaches about 3.50 meters.

The water of the Baltic Sea contains less oxygen than the water of other seas, especially in deeper layers. As a result, plants and animals cannot thrive in large areas.

The large rivers Oder, Vistula, Neman, Daugava, Neva and Torneälven flow into the Baltic Sea. They also carry wastewater and artificial nutrients, which damage the natural habitats of animals and plants.

There are fewer species in the Baltic Sea than in the North Sea. However, many fish species repeatedly migrate from the North Sea into the Baltic Sea, including cod, whiting, dab and plaice. Herring and flounder are also found in the Baltic Sea. In recent years, sprat numbers have even increased significantly in the western Baltic Sea. Some fish species migrate from rivers into the Baltic Sea. Others live in the sea but lay their eggs in rivers, such as sea trout.

Eels are born in the sea, migrate into rivers, and return to the sea a few years later. Jellyfish, starfish and lugworms are also found in the Baltic Sea. It is also home to several large mammals, such as grey seals, Baltic ringed seals, harbor porpoises and white-beaked dolphins.

Many birds spend the winter in the southern Baltic Sea, where it is not as cold as in more northerly or easterly areas. It is estimated that around 9 million birds from 30 different species spend the winter here each year.

The countries around the Baltic Sea have large forested areas, which sometimes extend all the way to the shore. Pines often grow there, and beech and birch trees are less common. Typical sea plants found here include common eelgrass, sea lettuce, saw-wrack and bladderwrack. All kinds of bushes, herbs and grasses also thrive on the sandy ground along the coast.

If you're lucky, you may find amber while walking along the Baltic coast. This gemstone is formed from tree resin. Millions of years ago, drops of resin fell to the ground. Sometimes they formed large lumps. They were covered by layers of earth, and under the pressure, the drops and lumps turned to stone.

Amber has been used to make jewellery since ancient times. It is a soft material that is easy to work with. It has always been a prized commodity, attracting many traders to the Baltic region. It was only from the 19th century onwards that amber began to be mined directly from its deposits. Before that, people had to collect it on the beach. Especially during storms, the movement of the sea repeatedly uncovers pieces of amber.

In the past, any amber that was found had to be handed over to the ruler of the land. Today, you can keep amber you find on the beach. Sometimes you may come across special pieces known as inclusions. These stones contain smaller animals or plants trapped inside them. They are often very well preserved and show the remains of a living thing from prehistoric times.

There are no storm surges on the Baltic Sea like those on the North Sea, because the difference between high and low tide here is only 15 to 30 centimetres at most. Of course, there can also be severe storms on the Baltic Sea. Then the water along the coast rises much higher than usual, but nowhere near as high as on the North Sea.

We call such flooding a storm surge. It can also cause severe damage. In 1872, the water is said to have risen in some places to as much as 3.30 metres above its normal level. The village of Damerow on the island of Usedom was completely destroyed by the floods. But such water levels are rare. During severe storms, the water level is usually only about 1.5 to 2 metres higher than normal.

People along the Baltic Sea also try to protect the coast from further encroachment by the sea. Measures include building breakwaters and groynes. Dunes are stabilised by planting vegetation. Forests that extend to the coast in some places are carefully maintained. Sea walls are also built in areas at risk.

Millions of people spend their holidays in the state of Mecklenburg-Western Pomerania every year, most of them on the Baltic coast. They visit popular seaside resorts such as Barth, Boltenhagen, Graal-Müritz, Heiligendamm, Kühlungsborn and Warnemünde, as well as places on the Fischland-Darß-Zingst peninsula and along the coast of Schleswig-Holstein.

The seaside resorts of Binz, Göhren, Sellin and Sassnitz on the island of Rügen, and Bansin, Heringsdorf and Ahlbeck on the island of Usedom are especially popular. These resorts are home to magnificent villas and hotels built for wealthy Berliners during the German Empire.

In some places, piers have been built out into the sea. They are usually made of wood and stretch far out over the water. Some are more than 100 years old. Originally, ships were meant to dock here because the shore was too shallow. Today, they are especially popular for walks. You can also visit restaurants and cafés located on the piers.

The longest seaside pier is in Heringsdorf on the island of Usedom. It is 508 meters long, with a roof covering 300 meters.