Inland sea in the context of "Great Lakes of North America"

Marine life, sea life or ocean life is the collective ecological communities that encompass all aquatic animals, plants, algae, fungi, protists, single-celled microorganisms and associated viruses living in the saline water of marine habitats, either the sea water of marginal seas and oceans, or the brackish water of coastal wetlands, lagoons, estuaries and inland seas. As of 2023, more than 242,000 marine species have been documented, and perhaps two million marine species are yet to be documented. An average of 2,332 new species per year are being described. Marine life is studied scientifically in both marine biology and in biological oceanography.

By volume, oceans provide about 90% of the living space on Earth, and served as the cradle of life and vital biotic sanctuaries throughout Earth's geological history. The earliest known life forms evolved as anaerobic prokaryotes (archaea and bacteria) in the Archean oceans around the deep sea hydrothermal vents, before photoautotrophs appeared and allowed the microbial mats to expand into shallow water marine environments. The Great Oxygenation Event of the early Proterozoic significantly altered the marine chemistry, which likely caused a widespread anaerobe extinction event but also led to the evolution of eukaryotes through symbiogenesis between surviving anaerobes and aerobes. Complex life eventually arose out of marine eukaryotes during the Neoproterozoic, and which culminated in a large evolutionary radiation event of mostly sessile macrofaunae known as the Avalon Explosion. This was followed in the early Phanerozoic by a more prominent radiation event known as the Cambrian Explosion, where actively moving eumetazoan became prevalent. These marine life also expanded into fresh waters, where fungi and green algae that were washed ashore onto riparian areas started to take hold later during the Ordovician before rapidly expanding inland during the Silurian and Devonian, paving the way for terrestrial ecosystems to develop.

The Sea of Marmara, also known as the Sea of Marmora or the Marmara Sea, is a small inland sea entirely within the borders of Turkey. It links the Black Sea and the Aegean Sea via the Bosporus and Dardanelles straits, separating Turkey's European and Asian sides. It has an area of 11,350 km (4,380 sq mi), and its dimensions are 280 km × 80 km (174 mi × 50 mi). Its greatest depth is 1,370 m (4,490 ft).

The Great Lakes, also called the Great Lakes of North America, are a series of large interconnected freshwater lakes spanning the Canada–United States border. The five lakes are Superior, Michigan, Huron, Erie, and Ontario (though hydrologically, Michigan and Huron are a single body of water, joined at the Straits of Mackinac). The Great Lakes Waterway enables modern travel and shipping by water among the lakes. The lakes connect ultimately to the Atlantic Ocean via the Saint Lawrence River as their primary drainage outflow. The lakes are also connected to the Mississippi River basin through the Illinois Waterway.

The Great Lakes are the largest group of freshwater lakes on Earth by total area and the second-largest by total volume. They contain 21% of the world's surface fresh water by volume. The total surface is 94,250 square miles (244,106 km), and the total volume (measured at the low water datum) is 5,439 cubic miles (22,671 km), slightly less than the volume of Lake Baikal (5,666 cu mi or 23,615 km, 22–23% of the world's surface fresh water). Because of their sea-like characteristics, such as rolling waves, sustained winds, strong currents, great depths, and distant horizons, the five Great Lakes have long been called inland seas. Depending on how it is measured, by surface area, either Lake Superior or Lake Michigan–Huron is the second-largest lake in the world and the largest freshwater lake. Lake Michigan is the largest lake, by surface area, that is entirely within one country, the United States.

Hudson Bay, sometimes called Hudson's Bay (usually historically), is a large body of saltwater in northeastern Canada with a surface area of 1,230,000 km (470,000 sq mi). It is located north of Ontario, west of Quebec, northeast of Manitoba, and southeast of Nunavut, but politically entirely part of Nunavut. It is an inland marginal sea of the Arctic Ocean. The Hudson Strait provides a connection to the Labrador Sea and the Atlantic Ocean in the northeast, while the Foxe Channel connects Hudson Bay with the Arctic Ocean in the north. The Hudson Bay drainage basin drains a very large area, about 3,861,400 km (1,490,900 sq mi), that includes parts of southeastern Nunavut, Alberta, Saskatchewan, Ontario, Quebec, all of Manitoba, and parts of the U.S. states of North Dakota, South Dakota, Minnesota, and Montana. Hudson Bay's southern arm is called James Bay.

The Eastern Cree name for Hudson and James Bay is Wînipekw (southern dialect) or Wînipâkw (northern dialect), meaning muddy or brackish water. Lake Winnipeg is similarly named by the local Cree, as is the location for the city of Winnipeg.

The Baltic Sea is an arm of the Atlantic Ocean that is enclosed by the countries of Denmark, Estonia, Finland, Germany, Latvia, Lithuania, Poland, Russia, Sweden, and the North and Central European Plain regions. It is the world's largest brackish water basin.

The sea stretches from 53°N to 66°N latitude and from 10°E to 30°E longitude. It is a shelf sea and marginal sea of the Atlantic with limited water exchange between the two, making it an inland sea. The Baltic Sea drains through the Danish straits into the Kattegat by way of the Øresund, Great Belt and Little Belt. It includes the Gulf of Bothnia (divided into the Bothnian Bay and the Bothnian Sea), the Gulf of Finland, the Gulf of Riga and the Bay of Gdańsk.

The Bohai Sea (Chinese: 渤海; pinyin: Bó Hǎi; lit. 'Bo Sea') is a gulf/inland sea approximately 77,000 km (30,000 sq mi) in area on the east coast of Mainland China. It is the northwestern and innermost extension of the Yellow Sea, to which it connects via the Bohai Strait. It has a mean depth of approximately 18 meters (59 ft), with a maximum depth of about 80 meters (260 ft) located in the northern part of the Bohai Strait.

The Bohai Sea is enclosed by three provinces and one direct-administered municipality from three different regions of China—Liaoning Province (of Northeast China), Hebei Province and Tianjin Municipality (of North China), and Shandong Province (of East China). It is the center of the Bohai Economic Rim, and its proximity to the Chinese capital of Beijing and the municipality of Tianjin makes it one of the busiest seaways in the world. The entrance to the Bohai Sea is considered a part of the territorial sea of the People's Republic of China due to the presence of the Miaodao islands. China declared the Bohai sea to be part of its inland waters in 1958.

The Paratethys Sea, Paratethys Ocean, Paratethys realm or just Paratethys (meaning "beside Tethys"), was a large shallow inland sea that covered much of mainland Europe and parts of western Asia during the middle to late Cenozoic, from the late Paleogene to the late Neogene, and is regarded as the largest inland sea in history. At its greatest extent, it stretched from the region north of the Alps over Central Europe to the Aral Sea in Central Asia.

Paratethys formed about 34 Mya (million years ago) at the beginning of the Oligocene epoch, when the northern region of the Tethys Ocean (Peri-Tethys) was separated from the Mediterranean region of the Tethys realm due to the formation of the Alps, Carpathians, Dinarides, Taurus and Elburz mountains. Paratethys was at times reconnected with the Tethys or its successors (the Mediterranean Sea or the Indian Ocean) during the Oligocene and the early and middle Miocene times, but at the onset of the late Miocene epoch, the tectonically trapped sea turned into a megalake from the eastern Alps to what is now Kazakhstan. From the Pliocene epoch onward (after 5 million years ago), Paratethys became progressively shallower. Today's Black Sea, Caspian Sea, and Aral Sea are remnants of the Paratethys Sea.

A brown-water navy or riverine navy, in the broadest sense, is a naval force capable of military operations in inland waters (rivers, lakes and inland seas) and nearshores. The term originated in the United States Navy during the American Civil War, when it referred to Union forces patrolling the muddy Mississippi River, and has since been used to describe the small gunboats and patrol boats commonly used in rivers, along with the larger "mother ships" that supported them.

Brown-water navies are typically only used for patrolling and enforcing internal waters, in contrast to blue-water navies, which can independently conduct operations in the open oceans and project power far offshore. Green-water navies, which operate mainly in brackish estuaries, bays and shallow seas not too far off coasts (typically within the bounds of exclusive economic zones), fill the operational gap between brown-water and blue-water navies.