Europe is almost surrounded by semi-closed and closed seas, such as the
Adriatic, Mediterranean, Black, Azov, Caspian, Baltic and White seas.
Coastal landscape features range from dunes, cliffs, lagoons and river
deltas to very diverse islands, with numerous important marine and bird
areas, including 449 Ramsar sites in Western Europe. The Danube has the
largest delta in Europe, encompassing about 580 000 ha (113 000 ha of
which are permanently covered by water). The limited water exchange of
the semi-closed and closed seas with the open ocean makes these seas very
sensitive to pollution, which increased dramatically between the 1970s
and 1990s, although this trend has been halted and even reversed in a
few places in the past ten years. The open coasts of the Atlantic show
impacts from land-based pollution, offshore oil and gas, and shipping
operations and accidental oil spills.