SWAMP (EN: bog, swamp, marsh, moor, morass; DE: Moor, Sumpf, Morast; FR: marais, marecage, tourbiere; ES: pantano, cienaga, fangal, tremedal; RU: болото) is the place on the Earth's surface, which is continuously or periodically abundantly moistured, is covered prevalently by the moisture-loving plants (hydrophytes), and is having the corresponding type of the soil-forming process with the possible peat accumulation. The prevalence of the processes of accumulation over the decomposition is the main difference of the swamp ecosystems from the others. The major processes, which are creating a swamp, are the slow exchange of oxygen and of the ions of the mineral substances within the still water.

They understand the swamp as the peat bog, when, as the result of the process of the peat accumulation, the root system of the majority of the plants is situated within the deposited layer of peat and does not reach the underlying mineral soil. On average, the minimal thickness of the layer of peat in this case may be assumed in the natural state to be equal to 30 centimetres. However, this value will vary, depending on the composition of the peat-forming plants. They usually name as the peat deposit the peat bog with the thickness of peat, and with the reserves, which are sufficient for its industrial development. Swamps may be found within all the climatic zones of the Earth's globe, but the process of the peat accumulation is characteristic only for the individual zones.

The total area of the swamps within the world amounts to approximately 3.5 million square kilometres, of which approximately 50% are the peat bogs with the depth of the peat more than 0.5 metres. The largest territories, which are covered by swamps, are concentrated within the USSR, Canada, Finland, and USA. Within the USSR, the area of the peat bogs, swamped meadows and forests, not counting the swamped spaces of the tundra, are more than 2.1 million square kilometres; there has the highest percentage of the swampiness the tundra zone; the peat bogs, and prevalently the reserves of peat, are concentrated within the forest zone. The emergence and development of the swamps are conditioned by the interaction of the series of factors: climate, relief of the terrain, composition of the soils within the drainage basin, vegetation, and so on.

According to the composition of the vegetative cover and peat, swamps or their separate places are subdivided into the eutrophic (lower), mesotrophic (transitional), and oligotrophic (upper). On the eutrophic swamps (within the valleys of the rivers, along the shores of the lakes, within the places with the emergence of the water sources), there grow the plants, which are more demanding for the mineral nutrition, namely, alder, spruce, willows, birch, cane, horsetail, bog-bean, cinquefoil, sedges, green mosses, and others; on the oligotrophic swamps (usually on the flat drainage basins), there grow the less demanding plants, namely, pine, heather bushes, cotton grass, certain species of the sphagnum mosses. The drainage of the swamps sharply changes the regime of the water-mineral nutrition, and leads to the change for the composition of the vegetative cover.

After the drainage, and after the conducting of the necessary meliorative works, they use swamps for the purposes of agriculture or forestry, and use peat bogs for the extraction of peat for fuel, fertilizers, and so on. The individual swamps within the USSR, with the habitat of the rare plants, animals, and birds, with the growth of the medicinal plants, which are having the water protection significance, and also representing the significant scientific interest, have been taken under the protection, and are not subject to mastering.