Geography of Asia though the Middle East is a division of Asia. The demarcation between Asia and Africa is the isthmus of Suez and the Red Sea. The border with Europe starts with the coast of the eastern Mediterranean, even though Turkey in the Near East extends partly into the Aegean Islands and includes Istanbul on the European side of the Bosphorus. On the north the boundary between the continents of Asia and Europe is commonly regarded as running through the Dardanelles, the Sea of Marmara, the Bosporus, the Black Sea, the Caucasus Mountains, the Caspian Sea, the Ural River to its source,
North Sea sea grass used to coat huge tracts of ocean floor, but have been damaged by trawling and dredging have diminished its habitat and prevented its return. Invasive Japanese seaweed has spread along the shores of the sea clogging harbours and inlets and has become a nuisance. Due to the heavy human populations and high level of industrialization along its shores, the wildlife of the North Sea has suffered from pollution, overhunting, and overfishing. Flamingos and pelicans were once found along the southern shores of the North Sea, but became extinct over the 2nd millennium. Walruses frequented the Orkney Islands through