Marsh
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What is a marsh?
A marsh is a type of wetland ecosystem distinguished by poor drainage, mineral soils, and plant life dominated by grasses rather than trees. Grasses, grasslike sedges, and reeds or rushes are common. Marshes are typically found at river mouths, especially where deltas have formed, with the Mississippi River delta being a prime example in the United States.
These areas feature a steady water supply and rich sediment deposits, creating an ideal environment for marsh grasses. The fibrous roots of these grasses help bind the mud and slow water flow, which encourages the spread of both the delta and the marsh.
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How is a marsh different from other types of wetlands?
A marsh is a type of wetland ecosystem distinguished by its poorly drained mineral soils and plant life dominated by grasses, grasslike sedges, and rushes. This is unlike a swamp, where trees dominate. Marshes are frequently found at river mouths, especially where extensive deltas have formed, and along low seacoasts, inside barrier bars and beaches, in estuaries, and on deltas. Salt marshes are among the most productive natural systems.
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What kinds of plants are commonly found in marshes?
Marshes are wetland ecosystems characterized by poor drainage and plant life dominated by grasses, sedges, and rushes. Marshes are different from swamps, which are dominated by trees.
Examples of plants commonly found in marshes:
* Wild rice
* True rice
* Common reed
* Giant reed
* Sea reed
* Reed canary grass
* Reedgrass, or bluejoint
* Bur reed
* Reed mace
* Salt marsh grasses
* GlasswortsThese plants are specially adapted to survive in wet and saline habitats.
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What animals live in marshes?
Marshes, a type of wetland ecosystem, are home to a variety of animal life. These ecosystems are characterized by poorly drained mineral soils and plant life dominated by grasses, sedges, and rushes.
Many creatures have adapted to marsh environments:
* Invertebrates Some invertebrates have adapted to the limited oxygen supplies in marsh water. For example, rat-tailed maggots use a telescoping tail-breathing tube to get air at the water surface. Also, some nematodes can live without oxygen.
* Birds Many species of birds, such as marsh wrens, rails, coots, and cranes live in marshes.
* Fish Ostariophysans are the dominant fishes that live in freshwater habitats like marshes.
* Insects Insects are the principal land animals found on marshes.6 Britannica SourcesCreated from Britannica articles using AI. AI can make mistakes, so verify using Britannica articles. -
How do marshes help the environment?
Marshes, a type of wetland ecosystem, provide habitats for plants, algae, animals, and other life forms, and act as refuges for rare and endangered species. Marshes contribute to the health of the environment by playing a key role in nutrient cycling, can affect the export of organic materials, and act as sinks for inorganic nutrients and atmospheric carbon. Marshes can also protect shorelines, recharge groundwater aquifers, and cleanse polluted waters.
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What problems do marshes face and how can people protect them?
Marshes face significant problems, including human disturbances like draining and filling for agriculture and construction, contamination from agricultural chemicals, and invasive species that disrupt native ecosystems. Climate change also poses a threat, potentially leading to the decomposition of peatlands and the release of greenhouse gases.
People can protect marshes through local and national policies, international agreements like the Ramsar Convention, and water management plans that reduce freshwater withdrawals. Additionally, conservation efforts, wildlife habitat development, and native planting can help prevent soil erosion and the spread of invasive species.
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Marsh, type of wetland ecosystem characterized by poorly drained mineral soils and by plant life dominated by grasses. The latter characteristic distinguishes a marsh from a swamp, whose plant life is dominated by trees. The number of plant species in marshes is few compared with those that grow on well-watered but not waterlogged land. Grasses, grasslike sedges, and reeds or rushes are of major importance. Wild rice is of some commercial importance, but true rice is undoubtedly by far the most important marsh plant and supplies a major portion of the world’s grain.
Marshes are common at the mouths of rivers, especially where extensive deltas have formed. The river brings a steady supply of water. The gradient of the river approaches zero at the sea, where flow is sluggish. Because the delta is deposited by sediment settling from the river water, the land that is built will be poorly drained at its driest and will often be underwater. Sediment supplied by the river has often been eroded from the surface soils of the drainage basin and is thus very rich. The combination of water supplied steadily at a low rate over a waterlogged but rich soil creates a perfect environment for marsh grasses.
Fibrous-rooted grasses bind the muds together and further hinder water flow, thus encouraging the spread of both the delta and the marsh. Marshes occur in the deltas of most of the world’s great rivers. In Europe well-known river-mouth marshes include those of the Camargue in the Rhône Delta, the Guadalquivir in Spain, and the Danube in Romania, all of which are famous as bird sanctuaries. In the Middle East, both the Nile Delta and the delta of the Tigris–Euphrates have extensive marshes of historical importance. The marsh dwellers of the Iranian marshes have developed a unique culture adapted to life in the wetlands. Marshes occur in the deltas of the Mekong in Vietnam and the Amazon in Brazil. In the United States the most extensive delta marshes are those of the Mississippi River.
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Some low-lying areas with poor drainage at the heads of more extensive drainage patterns contain wetlands. A well-known example is the Pripet Marshes and fens that historically have served as the natural boundary between Poland and Russia. In some places basinlike depressions in Earth’s surface trap waters and make wetlands. Most such areas are drained someplace along their rim by a river that is impeded at that point sufficiently to dam water at times of high flow and create marshes and swamps. The world’s two largest rivers, the Amazon and the Congo, fall into this category. Both of the great basins named after these rivers have extensive wetlands. The papyrus marshes of the upper Nile in South Sudan lie above dams of resistant rocks of the cataracts.
The Okavango Marshes east of the Kalahari desert in Botswana are perhaps the best example of marshes formed in an interior, closed basin that has no drainage. Other basins without outlets like that of the Great Salt Lake in Utah have accumulated too much salt for marsh growth.
The Florida Everglades constitutes a unique marsh–swamp combination growing on a limestone base. Because the region is near sea level, the water from the abundant rains does not drain but remains on the surface. The Everglades is similar to a huge, shallow, slowly flowing river. The area is an ideal marsh habitat, but the Everglades is different from usual marshes. The soils are alkaline because of the limy base, and the water is clear.
Some areas, such as the northern Great Plains of the United States, have so many small marshes that they are a characteristic of the landscape. These small marshes formed because the landscape left by the retreat of glacial ice was so irregular and so poorly drained that countless little depressions were filled with water each spring. As snow melted, the depressions supported the growth of temporary marshes, which then dried up during the summer. Larger depressions were occupied by ponds. These gradually became marshy as they filled in with sediment.
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Salt marshes, which are extensive along the east coast of the United States and are also common in the Arctic, northern Europe, Australia, and New Zealand, are formed by seawater flooding and draining, which exposes flat areas of intertidal land. Salt marsh grasses will not grow on permanently flooded flats; growth is also prevented where the flooded land is subject to strong currents and is therefore unstable.
Salt marshes are among the most productive natural systems. Productivities of more than 3,000 grams per square metre per year have been reported for the most productive parts of salt marshes, the tall Spartina alterniflora stands growing along tidal creeks. These values correspond to nearly 30 tons per acre per year and are equal to the highest values that have been achieved in agriculture.