swamp

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swamp,

shallow body of water in a low-lying, poorly drained depression, usually containing abundant plant growth dominated by trees, such as cypress, and high shrubs. Swamps develop in moist climates, generally in such places as low-lying coastal plains, floodplains of rivers, and old lake basins or in areas where normal drainage has been disrupted by glacial deposits. In the United States, swamps cover approximately 100,000 sq mi (260,000 sq km), most of them occurring as small swamps in northeastern states that were covered with glaciers in the past. The most extensive swamps are found along the Atlantic and Gulf coastal plains, notable examples being the EvergladesEverglades,
marshy, low-lying subtropical savanna area, c.4,000 sq mi (10,000 sq km), S Fla., extending from Lake Okeechobee S to Florida Bay. Characterized by water, sawgrass, hammocks (islandlike masses of vegetation), palms, pine and mangrove forests, and solidly packed black
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 of S Florida, Great Dismal SwampGreat Dismal Swamp,
SE Va. and NE N.C. With dense forests and tangled undergrowth, the wetlands are a favorite site for sportsmen and naturalists. It once may have covered nearly 2,200 sq mi (5,700 sq km) but has been reduced by drainage to less than 600 sq mi (1,550 sq km).
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 of Virginia, and Okefenokee SwampOkefenokee Swamp
, c.600 sq mi (1,550 sq km), c.40 mi (60 km) long and averaging 20 mi (32 km) in width, SE Ga., extending into N Fla. It is a saucer-shaped depression with low ridges and small islands rising above the water and vegetation cover.
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 of Georgia and N Florida. Because the bottom of a swamp is at or below the water table, swamps serve to channel runoff into the groundwater supply, thus helping to stabilize the water table. During periods of very heavy rains, a swamp can act as a natural flood control device, as excess runoff can be temporarily stored in its basin. Swamp vegetation varies with climate. Grasses, rushes, and sphagnum moss predominate in temperate climates; cypress and mangrove predominate in more tropical regions. Lush vegetation provides great protection for nesting waterfowl and fish as well as a hospitable habitat for many types of small mammal such as beaver and otter. Swamps that are drained make excellent agricultural land because of the high organic content of the bottom sediments. In addition, rising land values and demand have encouraged the drainage of many swamplands, such as coastal Florida, for home development. However, a problem associated with recently drained swamps is oxidation of the thick peat deposits forming the soil, which can result in subsidence of the land and such problems as cracked walls, broken underground pipes, and buckled roadways. The increased use of drained swampland for urban construction, with its associated acres of blacktop paving and storm sewers, results in greater runoff and increases the probability of flooding and pollution in these regions. Swamp drainage also destroys the nesting areas of many wildlife species. Thus, environmentalists have urged, with increasing success, the slowing down of swamp drainage. There are a variety of local terms for swamps, including bogbog,
very old lake without inlet or outlet that becomes acid and is gradually overgrown with a characteristic vegetation (see swamp). Peat moss, or sphagnum, grows around the edge of the open water of a bog (peat is obtained from old bogs) and out on the surface.
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, marsh, fen, and moor. However, bog usually refers to a swampy depression with a thick mat of living and dead organic matter floating on the water surface and a low level of oxygen in the water below. Marsh implies a large area of wet land where the dominant vegetation consists of low-lying grasses, rushes, and sedges.

Swamp

 

an abundantly wet piece of land on which unde-composed organic materials accumulate and eventually turn into peat. In a narrower sense the swamp is identified with the peat bog and is defined as an abundantly wet piece of land covered with a layer of peat not less than 30 cm deep (wet); abundantly wet land expanses without peat or with a layer of peat less than 30 cm deep are called marshlands. Swamps have great significance for the national economy. The peat obtained after draining a swamp is used as fertilizer, fuel, and cattle bedding; from it are extracted a number of valuable chemical products (ammonia, tar, and others); slabs of incompletely decomposed peat are used in building. Swamps are basically concentrated in the northern hemisphere, largely in the forested zone. The total area under swamps is approximately 350 million hectares. Within the USSR, swamps are distributed in the northern European part, in Poles’e, in Western Siberia, on Kamchatka, and in other regions.

The pioneer of the study of swamps and the nature of peat in Russia was M. V. Lomonosov. In 1766, J. G. Lehmann gave the first classifications of peat with regard to the plant remains in them. In 1810, G. I. Endel’man published a book on the drainage of swamps, in which he distinguished peats by their inflammability. The work of the I. I. Zhilinskii expedition, in the years 1873–98, on swamp drainage in Poles’e, in Moscow, and other provinces produced valuable scientific information. G. I. Tanfil’ev made important contributions to the study of the vegetation and geography of swamps. The first division of the swamps of European Russia into districts was made by A. V. Fomin (1898). In the 20th century the development of the study of swamps is connected with the names V. S. Dokturovskii and V. N. Sukachev, who published general manuals on the study of swamps. Dokturovskii was the first in the USSR to apply the pollen method of studying peat and to study the development of peat bogs by geological periods. V. N. Sukachev, R. I. Abolin, and others did in-depth investigations of the swamps of Pskov. Large contributions to the study of swamps were made by D. L. Gerasimov and V. V. Kudriashov. Gerasimov studied the geography and stratigraphy of swamps, including the details of the structure of cross sections of peat in connection with the process of peat formation, and Kudriashov developed an original theory of the growth and development of peat bogs. Among foreign scientists in the beginning of the 20th century who occupied themselves with questions of swamp study were K. A. Weber in Germany and A. K. Cajander in Finland; Swedish studies also exist. The works of French and Dutch swamp specialists appeared somewhat earlier. The compendium on swamps of L. Lesquereux (1884) was particularly important.

Swamps are formed as a result of soil swamping or the growing over of basins. In a temperate climate basins turn into swamps because of the close level of the groundwaters. The accumulation of moisture is aided by a cover of living plants (especially moss—common haircap moss and others) and, even more, by a dead, water-absorbing grass matting. Anaerobic conditions are created in the soil and soil swamping begins. Basins turn into swamps in different ways. Upgrowth occurs when clay or sand is deposited on the bottom of the basin and then the remains of, primarily, microscopic water animals (plankton) and bottom animals (benthos) and plants accumulate. These remains form sapropel. The basin gets shallower and plants establish themselves, at first immersed ones (pondweed, hornwort, and others), then water lilies with floating leaves or plants whose stalks emerge from the water (bulrushes, reeds). The remains of plants begin to predominate in the bottom sediments (sapropelic peat). Only “windows” of water remain of the former lake, and it is transformed into a swamp. Overgrowth occurs when the surface of the basin becomes covered with an unstable carpet (quagmire) formed by the rhizomes of grasses (sedge, buckbean, and others) or by mosses. The carpet starts growing from the shores and eventually covers the entire lake. Mechanical filling in occurs in lakes with peat shores when the crumbly peat is washed off and settles to the bottom. The basin gets shallower and becomes overgrown with vegetation.

According to the nature of the vegetation and the nourishment of the plants, one may distinguish low, transitional, and raised swamps. Eutrophic plants (requiring minerals) are characteristic of low swamps, which are located in low places (for example, in river valleys). The central part of the swamp lies level with or below the surrounding land, and sometimes its surface is inclined. The types of low swamps are the alluvial and the subsoil. Alluvial swamps form in river valleys and along lake shores; they are rich in mineral salts. The highly ashen peat in them is mixed with sand and silt brought in by river water, snow runoff, and rain. In a temperate climate these swamps are forested with alder, birch, and sometimes conifers and are known as sogry; swamps are also grassy, with sedge, reeds, and cattails. There are broad grassy swamps called plavni in the deltas of the Dnieper, Don, Volga, Kuban’, Danube, and Amu Darya rivers. There is a large quantity of flowering plants on allu-vially fed swamps, and mosses are weakly developed. Swamps fed by the subsoil often form under the slopes of river terraces, at the sources of springs. A dense carpet of mosses and weak development of grasses is characteristic of them. The fauna of low swamps is diverse: water voles, field mice, often otters, and a particularly large number of birds (sandpipers, moorhens, corncrakes, and others). During the nesting season and migration there are many geese and ducks. In the southern Russian plavni one encounters wild boar, jungle cats, flamingos, and pelicans. Mesotrophic plants (of moderate mineral nourishment) are characteristic of transitional swamps; birches are common, pines occur frequently, and sedge and a continuous carpet of sphagnum mosses are found. Oligotrophic plants (which do not demand ashen elements) are characteristic of raised swamps. The water in these swamps is sharply acidic, the color of tea, and rich in humic acids. The peat is slightly ashen (1.5–4.0 percent ash). Raised swamps are usually located on watersheds. Their surface is domed in the middle because the peat in the center of the swamp accumulates faster than on the periphery. The flora of such swamps is poor; Of the trees, there are pines or, to the east of the Enisei River, larches; of the shrubs, there are heaths, including marsh tea, leather-leaf, and cranberry; of the grasses, there is sheathing cotton grass, scheuchzeria, and beak rush. The continuous carpet of sphagnum mosses which forms the top layer of the peat is up to 5 m thick. The growth of moss can be determined by sundew; every year the sundew forms a rosette of leaves on the surface of the moss, which is then buried by the moss and remains in the peat; the distance between the rosettes corresponds to the yearly growth of the moss carpet. Another method of determining the yearly growth of the peat is by cross sections of pine root collars. The average growth of peat in 1,000 years is about 1 m. The oldest peat bogs were formed approximately 1 million years ago.

Two types of raised swamps may be distinguished; forested raised swamps are covered with low pines (east of the Enisei River, with larches), and in the low-lying stratum they are covered by heather bushes with cotton grass and a carpet of sphagnum. String raised bogs have a wavy surface with long banks (or hummocks) of peat, up to 70 cm high, and depressions (furrows) between the banks. The vegetation on the rises is the same as in forested swamps, but the pines on the rises are lower (to 1 m high) and often solitary. In the furrows there are sparse and low-growing grasses— such as cotton grass and scheuchzeria—and water-saturated, partially submerged sphagnum. In the course of formation the raised swamp passes through a series of stages, beginning with a basin or marshy land. Each stage leaves a peat layer of a particular botanical composition. The fauna of raised swamps is poor—moose, wolves (in summer), caper-caillie, willow grouse, and cranes.

The role of swamps in the landscape and their types differ in various zones. In arctic tundra the surface of the swamp is broken up by frost cracks into polygons with diameters of 5 to 20 m. Further south, in typical tundra, forested tundra, and in the north of the forested zone, swamps are usually formed in the summer by runoff. Freezing up in the winter, the swamp forms peat hillocks up to 10 m high, with a permanently frozen center (high-hillock and low-hillock swamps). Swamps in the tundra cover 50 percent of the land and more; not peat but mineral swamps predominate there. In the taiga zone of Europe and Western Siberia domed (raised) sphagnum swamps are usual. The expanse of peat bogs (in the general expanse of swamp) is greatest in this zone. In the forested steppe the peat bogs are eutrophic and low-lying. In the steppe zone peat forms occasionally (generally under water); swamps there have tall grasses— reeds and cattails. In the USSR the drainage, reclamation, and development of swamps for the production of forage crops, vegetables (cabbage, carrots), grains (oats, rye), industrial crops (hemp, flax), and silage has been widely carried out. Extensive swamps of the Iakhroma valley (Moscow Oblast) are under cultivation; citrus fruits are cultivated on the swamps of Kolkhida; a plan of reclamation for the swamps of the Barabinskaia lowland has been drawn up, and the Poles’e swamp has been put under cultivation in large part.

REFERENCES

Kats, N. Ia. Bolota i torfianiki. Moscow, 1941.
Kats, N. Ia. Tipy bolot SSSR i Zapadnoi Evropy i ikh geograficheskoe rasprostranenie. Moscow, 1948.
Tiuremnov, S. N. Torfianye mestorozhdeniia i ikh razvedka, 2nd ed. Moscow-Leningrad, 1949. P’iavchenko, N. I. Lesnoe bolotovedenie. Moscow, 1963.

N. IA. KATS

What does it mean when you dream about a swamp?

When we dream about being in a swamp, we are often feeling bogged down with something. Water often symbolizes emotion, so it could be our emotional life that is causing us to feel bogged down. (See also Slow Motion).

swamp

[swämp]
(ecology)
A waterlogged land supporting a natural vegetation predominantly of shrubs and trees.

swamp

a. permanently waterlogged ground that is usually overgrown and sometimes partly forested
b. (as modifier): swamp fever