A swamp is part of a wetland ecosystem.
Swamps are forested, low, spongy land generally saturated with water and covered with trees and aquatic plants.
They can be found on all continents except Antarctica.
Swamps form around lakes, rivers and streams. Rain and seasonal flooding cause water levels to fluctuate. In the wet soil, water-tolerant vegetation grows and helps maintain a moist, swampy condition.
The water of a swamp may be fresh water, brackish water or seawater.
Swamp vegetation varies with climate. Grasses, rushes, and sphagnum moss predominate in temperate climates; cypress and mangrove predominate in more tropical regions.
The largest swamp in the world is the Amazon River floodplain, which is particularly significant for its large number of fish and tree species.
In the United States, swamps cover approximately 260,000 square kilometers (100,000 square miles), most of them occurring as small swamps in northeastern states that were covered with glaciers in the past.
The Atchafalaya Basin, or Atchafalaya Swamp is the largest wetland and swamp in the United States. Located in south central Louisiana, it is a combination of wetlands and river delta area where the Atchafalaya River and the Gulf of Mexico converge.
The Okefenokee Swamp is considered to be one of the Seven Natural Wonders of Georgia. The Okefenokee is the largest “blackwater” swamp in North America. It covers roughly 1,800 square kilometers (700 square miles) and is located in the southeastern corner of Georgia. Okefenokee is a Native American word that means “trembling earth.”
Other famous swamps in the United States are the forested portions of the Everglades, Barley Barber Swamp, Great Cypress Swamp and the Great Dismal Swamp.
The freshwater swamps between the Tigris and Euphrates Rivers in the Middle East are so rich in biodiversity that the area is called the “Fertile Crescent.” The Fertile Crescent is recognized as the birthplace of civilization and the site of the first cities. The earliest recorded written language and the first recorded use of the wheel occurred around these swamps.
Swamps are often named for the type of trees that grow in them, such as cypress swamps or hardwood swamps.
Swamps are delightfully described in their primeval condition by William Bartram in his account Travels Through North and South Carolina, Georgia, East and West Florida, written in 1791. These were the swamps that Francis Marion used so successfully to escape the British forces during the Revolutionary War and the source of his nickname, “the old swamp fox.”
Swamps are among the most valuable ecosystems on Earth. They act like giant sponges or reservoirs. When heavy rains cause flooding, swamps and other wetlands absorb excess water, moderating the effects of flooding. Swamps also protect coastal areas from storm surges that can wash away fragile coastline. Saltwater swamps and tidal salt marshes help anchor coastal soil and sand.
Swamps that are drained make excellent agricultural land because of the high organic content of the bottom sediments.
Ancient swamps are a source of the fossil fuel coal. Coal is formed from plants that died millions of years ago. The plant matter settled in layers at the bottom of swamps, where lack of oxygen kept it from decaying completely. Over time, pressure from accumulating layers caused the vegetation to harden, or fossilize, into coal. For centuries, coal has been burned and used as fuel. Deposits of this fossil fuel can be found on every continent.