Ocean current the windthe Coriolis effect plays a role in their behaviours. The thermohaline circulation is a part of the large-scale ocean circulation that is driven by global density gradients created by surface heat and freshwater fluxes. The adjective "thermohaline" derives from "thermo-" referring to temperature and "" referring to salt content, factors which together determine the density of sea water. Wind-driven surface currents (such as the Gulf Stream) travel polewards from the equatorial Atlantic Ocean, cooling en route, and eventually sinking at high latitudes (forming North Atlantic Deep Water). This dense water then flows into the ocean basins. While the bulk
Europe maritime borders consist of the Arctic Ocean to the north, the Atlantic Ocean to the west, and the Mediterranean, Black, and Caspian Seas to the south. Land relief in Europe shows great variation within relatively small areas. The southern regions are more mountainous, while moving north the terrain descends from the high Alps, Pyrenees, and Carpathians, through hilly uplands, into broad, low northern plains, which are vast in the east. This extended lowland is known as the Great European Plain, and at its heart lies the North German Plain. An arc of uplands also exists along the north-western seaboard, which