The Baltic Sea, located in Northern Europe, is a brackish sea connected to the North Sea through the Danish Straits. It is surrounded by countries including Sweden, Finland, Russia, Estonia, Latvia, Lithuania, Poland, Germany, and Denmark. Its unique geographical location and characteristics contribute to its biological, geographical, and climatic features, making it an interesting subject of study.
The Baltic Sea covers an area of approximately 377,000 square kilometers, making it one of the largest brackish water bodies in the world. The sea is relatively shallow, with an average depth of about 55 meters, and its maximum depth is around 459 meters. The Baltic Sea is divided into several basins, each with distinct characteristics. The sea's major gulfs include the Gulf of Bothnia, the Gulf of Finland, and the Gulf of Riga. Its major islands include Gotland, Öland, and Saaremaa.
The Baltic Sea's connection to the North Sea is crucial for its water renewal. Saltwater from the North Sea flows into the Baltic Sea through the Danish Straits, while freshwater from rivers and precipitation dilutes the seawater, leading to its brackish nature.
The salinity of the Baltic Sea varies both horizontally and vertically. It generally decreases from the Danish Straits to the northern parts and from the surface to the bottom layers. The average surface salinity is around 7-8 PSU (Practical Salinity Units), much lower than the average ocean salinity of about 35 PSU. This gradient affects the sea's biodiversity, as both marine and freshwater species can be found, though the species diversity is lower than that of fully marine environments.
The Baltic Sea's climate is influenced by its geographical location, with the northern parts experiencing colder temperatures and the southern parts experiencing relatively milder conditions. Winters can be severe, with significant portions of the sea freezing over, especially in the Bothnian Bay and the Gulf of Finland. Ice breaking ships are often required to maintain shipping routes during winter months.
Despite its low salinity, the Baltic Sea supports a diverse range of organisms. The sea is home to various fish species, such as herring, cod, and flounder, which are important to both the ecosystem and regional fisheries. Seals and sea birds are also common, feeding on the abundant fish stocks.
Algae and plankton form the basis of the food web, supporting higher trophic levels. However, eutrophication, primarily caused by agricultural runoff, has led to algal blooms that can deplete oxygen levels in the water, resulting in "dead zones" where few organisms can survive.
The Baltic Sea is one of the busiest maritime areas in the world, with significant commercial shipping, fishing, and recreational activities. These activities, along with industrial and agricultural runoff, have led to pollution and environmental stress. Persistent organic pollutants, heavy metals, and excessive nutrients are among the key environmental concerns.
Efforts have been made to protect the Baltic Sea through international cooperation. The Helsinki Commission (HELCOM) is an intergovernmental organization dedicated to protecting the marine environment of the Baltic Sea. HELCOM's initiatives focus on reducing pollution, protecting biodiversity, and managing human activities to minimize their impact on the sea.
The Baltic Sea is a unique marine environment with its brackish nature, distinct ecosystems, and significant human influence. Its shallow waters, varying salinity, and seasonal ice cover distinguish it from other seas. Despite facing ecological challenges such as pollution and eutrophication, efforts to conserve and protect the Baltic Sea continue to be a priority for the surrounding countries. Understanding the complexities of this maritime environment is crucial for its preservation and sustainable use.
