29-579: The South Newport River is a 42.6-mile-long (68.6 km) river on the Atlantic coastal plain in the U.S. state of Georgia . It rises in Long County 3 miles (5 km) south of Walthourville and flows east-southeast, becoming the boundary between Liberty and McIntosh counties. It flows into Sapelo Sound, an arm of the Atlantic Ocean , south of St. Catherines Island . The river's name most likely
58-581: A different set of organisms. Saltwater marshes are found around the world in mid to high latitudes , wherever there are sections of protected coastline. They are located close enough to the shoreline that the motion of the tides affects them, and, sporadically, they are covered with water. They flourish where the rate of sediment buildup is greater than the rate at which the land level is sinking. Salt marshes are dominated by specially adapted rooted vegetation, primarily salt-tolerant grasses. Salt marshes are most commonly found in lagoons , estuaries , and on
87-522: A freshwater marsh, the ocean tides affect this form of marsh. However, without the stresses of salinity at work in its saltwater counterpart, the diversity of the plants and animals that live in and use freshwater tidal marshes is much higher than in salt marshes. The most severe threats to this form of marsh are the increasing size and pollution of the cities surrounding them. Ranging greatly in size and geographic location, freshwater marshes make up North America's most common form of wetland. They are also
116-576: A habitat for many species of plants, animals, and insects that have adapted to living in flooded conditions or other environments. The plants must be able to survive in wet mud with low oxygen levels. Many of these plants, therefore, have aerenchyma , channels within the stem that allow air to move from the leaves into the rooting zone. Marsh plants also tend to have rhizomes for underground storage and reproduction. Common examples include cattails , sedges , papyrus and sawgrass . Aquatic animals, from fish to salamanders , are generally able to live with
145-505: A habitat free from fish, which eat the eggs and young of amphibians. An example is the endangered gopher frog . Similar temporary ponds occur in other world ecosystems, where they may have local names. However, vernal pool can be applied to all such temporary pool ecosystems. Playa lakes are a form of shallow freshwater marsh in the southern high plains of the United States. Like vernal pools, they are only present at certain times of
174-457: A low amount of oxygen in the water. Some can obtain oxygen from the air instead, while others can live indefinitely in conditions of low oxygen. The pH in marshes tends to be neutral to alkaline , as opposed to bogs , where peat accumulates under more acid conditions. Marshes provide habitats for many kinds of invertebrates, fish , amphibians, waterfowl and aquatic mammals. Marshes have extremely high levels of biological production, some of
203-511: A maximum thickness of about 3 kilometers (10,000 ft) in the vicinity of Cape Hatteras, North Carolina . Despite being previously overlooked in research, the Atlantic Coastal Plain is now identified as a global biodiversity hotspot, with over 1500 endemic plant species, and ~70% habitat loss. This endemism is particularly high in the longleaf pine savannas and woodlands , along with the other herbaceous and fire dependent ecosystems of
232-473: A region in the East of England , the embanked marshes are also known as Fens . Some areas have already lost 90% of their wetlands, including marshes. They have been drained to create agricultural land or filled to accommodate urban sprawl . Restoration is returning marshes to the landscape to replace those lost in the past. Restoration can be done on a large scale, such as by allowing rivers to flood naturally in
261-664: Is a transfer from Newport, Rhode Island . This article related to a river in the US state of Georgia is a stub . You can help Misplaced Pages by expanding it . Atlantic coastal plain The Atlantic Plain is one of eight distinct physiographic divisions of the contiguous United States . Using the USGS physiographic classification system, the Atlantic Plain division comprises two provinces and six sections. The Coastal Plain province
290-476: Is about 135 km. The Coastal Plain of the United States includes all or portions of the states of Alabama , Arkansas , Delaware , Florida , Georgia , Kentucky , Maryland , Massachusetts , Mississippi , New Jersey , New York , North Carolina , Oklahoma , South Carolina , Rhode Island , Tennessee , Texas and Virginia . From the northeast, it begins on Cape Cod, Massachusetts and stretches to
319-614: Is differentiated from the Continental Shelf province simply based on the portion of the land mass above and below sea level. The lands adjacent to the Atlantic coastline are made up of sandy beaches, marshlands, bays, and barrier islands. It is the flattest of the U.S. physiographic divisions and stretches over 2,200 miles (3,500 km) in length from Cape Cod to the Mexican border and southward an additional 1,000 miles (1,600 km) to
SECTION 10
#1732869571179348-575: The Carolina Sandhills region as well as the Embayed and Sea Island physiographic provinces. The Atlantic Coastal Plain is sometimes subdivided into northern and southern regions, specifically the Mid-Atlantic and South Atlantic coastal plains. The Atlantic Plain is generally gently dipping undeformed Mesozoic and Cenozoic sediments, with the sedimentary wedge thickening toward the sea, reaching
377-485: The Yucatán Peninsula . The central and southern Atlantic Coast is characterized by barrier and drowned valley coasts. The coastal Atlantic plain features nearly continuous barriers interrupted by inlets , large embayments with drowned river valleys , and extensive wetlands and marshes . The Atlantic plain slopes gently seaward from the inland highlands in a series of terraces. This gentle slope continues far into
406-603: The longleaf pine woodlands and savannas of the Gulf Plain. 32°N 83°W / 32°N 83°W / 32; -83 Marsh In ecology , a marsh is a wetland that is dominated by herbaceous plants rather than by woody plants . More in general, the word can be used for any low-lying and seasonally waterlogged terrain. In Europe and in agricultural literature low-lying meadows that require draining and embanked polderlands are also referred to as marshes or marshland. Marshes can often be found at
435-662: The Atlantic and Gulf of Mexico , forming the continental shelf. The relief at the land-sea interface is so low that the boundary between them is often blurry and indistinct, especially along stretches of the Louisiana bayous and the Florida Everglades . The Atlantic Ocean has a broad, flat continental shelf that reaches a depth of 100 meters. The continental shelf off the Atlantic Ocean ranges in width from less than 1 km off Florida to more than 420 km off Maine. The average width
464-545: The ecoregion. Despite intermittent flooding, certain refugia have remained continuously terrestrial since at least the late Cretaceous (85-80mya), contributing to endemism. Generally speaking, despite the high diversity of soils, the soil is nutrient poor. This is primarily due to an abundance of well-drained soils, creating a primarily xeric character to the floral makeup of the Atlantic Plain. However, waterlogged soils are also notable, with wetlands and hammocks being important ecological features. The Eastern woodlands are
493-1052: The edges of lakes and streams, where they form a transition between the aquatic and terrestrial ecosystems . They are often dominated by grasses , rushes or reeds. If woody plants are present they tend to be low-growing shrubs, and the marsh is sometimes called a carr . This form of vegetation is what differentiates marshes from other types of wetland such as swamps , which are dominated by trees , and mires , which are wetlands that have accumulated deposits of acidic peat . Marshes provide habitats for many kinds of invertebrates , fish , amphibians , waterfowl and aquatic mammals . This biological productivity means that marshes contain 0.1% of global sequestered terrestrial carbon . Moreover, they have an outsized influence on climate resilience of coastal areas and waterways, absorbing high tides and other water changes due to extreme weather . Though some marshes are expected to migrate upland, most natural marshlands will be threatened by sea level rise and associated erosion . Marshes provide
522-627: The fringes of large rivers. The different types are produced by factors such as water level, nutrients, ice scour , and waves. Large tracts of tidal marsh have been embanked and artificially drained. They are usually known by the Dutch name of polders . In Northern Germany and Scandinavia they are called Marschland , Marsch or marsk ; in France marais maritime . In the Netherlands and Belgium, they are designated as marine clay districts. In East Anglia ,
551-447: The highest in the world, and therefore are important in supporting fisheries. Marshes also improve water quality by acting as a sink to filter pollutants and sediment from the water that flows through them. Marshes partake in water purification by providing nutrient and pollution consumption. Marshes (and other wetlands) are able to absorb water during periods of heavy rainfall and slowly release it into waterways and therefore reduce
580-422: The inland highlands in a series of terraces. The province's average elevation is less than 900 meters above sea level and extends some 50 to 100 kilometers inland from the ocean. The coastal plain is normally wet, including many rivers, marsh , and swampland . It is composed primarily of sedimentary rock and unlithified sediments and is primarily used for agriculture . The Atlantic Coastal Plain includes
609-499: The longleaf pine forests into central Florida, with South Florida slash pine flatwoods , Florida sand pine scrub and Florida dry prairie stretching into southern Florida. Longleaf pine woodlands also stretch further west, to eastern Texas. These consist of East Gulf and West Gulf longleaf pine flatwoods , bisected by the Mississippi Alluvial Plain . To the north, the Atlantic Coastal Plain also broaches into
SECTION 20
#1732869571179638-469: The magnitude of flooding. Marshes also provide the services of tourism, recreation, education, and research. Marshes differ depending mainly on their location and salinity . These factors greatly influence the range and scope of animal and plant life that can survive and reproduce in these environments. The three main types of marsh are salt marshes , freshwater tidal marshes , and freshwater marshes . These three can be found worldwide, and each contains
667-558: The mesic hardwood forests of the Middle Atlantic coastal forests , followed by the northern Atlantic coastal pine barrens . The southernmost Atlantic Plain contains the only Neotropical ecoregion of the continental USA, being the Everglades and Florida mangroves . The following species are largely endemic to the region. Amphibian diversity is especially notable in the Atlantic Plain. Some of these species' ranges may extend into
696-479: The most diverse of the three types of marsh. Some examples of freshwater marsh types in North America are: Wet meadows occur in shallow lake basins, low-lying depressions, and the land between shallow marshes and upland areas. They also happen on the edges of large lakes and rivers. Wet meadows often have very high plant diversity and high densities of buried seeds. They are regularly flooded but are often dry in
725-492: The original, predominant ecosystem of the Atlantic coastal plain. The Atlantic coastal plain upland longleaf pine woodland is an endemic plant community found in most of the Atlantic coastal plain, ranging from Virginia to northern Florida. These woodland savannas are reliant on sandy soils and are fire dependent, lest hardwoods start to dominate. Alongside longleaf pine , typically associated flora includes turkey oak and wiregrass . The Florida longleaf pine sandhill extends
754-463: The sheltered side of a shingle or sandspit . The currents there carry the fine particles around to the quiet side of the spit, and sediment begins to build up. These locations allow the marshes to absorb the excess nutrients from the water running through them before they reach the oceans and estuaries. These marshes are slowly declining. Coastal development and urban sprawl have caused significant loss of these essential habitats. Although considered
783-705: The southwest to South Padre Island, Texas . This is approximately 1,900 miles (3,100 km). This province consists of the following physiographic sections: the Embayed, Sea Island , Floridian , East Gulf Coastal Plain , Mississippi Alluvial Plain , and the West Gulf Coastal Plain . The rocks in the province consist, for the most part, of layers of sand and clay which are not yet hardened into sandstone and shale. The Coastal Plain features nearly continuous barrier islands interrupted by inlets, large embayments with drowned river valleys, and extensive wetlands and marshes. The Coastal Plain slopes gently seaward from
812-492: The summer. Vernal pools are a type of marsh found only seasonally in shallow depressions in the land. They can be covered in shallow water, but in the summer and fall, they can be completely dry. In western North America, vernal pools tend to form in open grasslands, whereas in the east, they often occur in forested landscapes. Further south, vernal pools form in pine savannas and flatwoods . Many amphibian species depend upon vernal pools for spring breeding; these ponds provide
841-654: The year and generally have a circular shape. As the playa dries during the summer, conspicuous plant zonation develops along the shoreline. Prairie potholes are found in northern North America, such as the Prairie Pothole Region . Glaciers once covered these landscapes, and as a result, shallow depressions were formed in great numbers. These depressions fill with water in the spring. They provide important breeding habitats for many species of waterfowl. Some pools only occur seasonally, while others retain enough water to be present all year. Many kinds of marsh occur along
#178821