Inlandseen

Inlandseen is the plural form in German for inland sea; the singular is Inlandsee. In English, the corresponding term is inland sea. An inland sea is a large body of seawater that lies largely within a landmass, typically with only limited contact with the open ocean through straits or channels, or in some cases with no direct outlet at all. Inland seas retain marine characteristics such as salinity, wave action, and marine ecosystems, which distinguish them from freshwater lakes despite being surrounded by land.

Notable examples commonly cited in geography include the Caspian Sea, which is the largest inland body of water by area, the Aral Sea, and the Sea of Azov in Eurasia. Some scholars treat the Black Sea or the Baltic Sea as marginal seas rather than inland seas, depending on the criteria used, while others include them in the broader category due to their enclosed geography and limited exchange with the global ocean.

Formation and evolution of inland seas result from tectonic processes, long-term sea-level changes, and fluctuations in river inflow. Over time, climatic shifts and human activities can alter their size, salinity, and ecological balance. The Caspian and Aral basins illustrate how diversions of major rivers and water management policies can dramatically reshape inland seas, affecting freshwater input, salinity, and habitat suitability.

Economic and ecological significance varies by region. Inland seas support fisheries, shipping routes, and resource extraction, but they also face environmental pressures such as pollution, invasive species, and salinity or water-level changes. Given their geopolitical sensitivity, inland seas often require regional cooperation to manage resources and cross-border impacts.