Near rivers and in flat areas along seacoasts are places in which marshes may be found. They also may be found in areas where there may not be any lakes or rivers, but where the ground is flat and water has collected. A marsh is a type of wetland that receives mineral-rich water from the ground and, often, water from nearby rivers and seas. The plant life in marshes is mostly grasses. This is the main difference between marshes and swamps, where trees are the main type of plants. Rice, one of the world's most important food crops, grows in marshy areas. Animals are abundant in marshes, and many bird sanctuaries have been created in river-mouth marshes around the world. How marshes formMarshes form in areas that receive water regularly but cannot quickly drain that water. A marsh at the mouth of a river, for example, will receive a steady but slow supply of water from the river. The water does drain, but at such a slow rate that it is essentially standing still. The river water deposits sediment, very fine rock and soil carried by the water, in the marsh. This sediment creates a rich but very watery mud in which the marsh grasses grow. Where marshes are foundFreshwater marshes can be found in all parts of the world along rivers as well as in low-lying inland areas. In the Middle East, both the Nile Delta and the delta of the Tigris and Euphrates rivers have extensive marshes of historical importance. The Okavango Marshes east of the Kalahari desert in Botswana are inland marshes, as are the marshes on the prairies of the United States. The Florida Everglades constitute a marsh and swamp system. Because the region is near sea level the water from the heavy rains does not drain but remains on the surface. Saltwater marshes are found on the east coast of the United States, in the Arctic, Northern Europe, Australia, and New Zealand. |