In temperate latitudes, mainly in the forest and forest-tundra zones, such a variety of wetlands as sphagnum bogs is formed. The predominant vegetation on them is moss sphagnum, thanks to which they got their name.
Description
These are high bogs, which are mainly formed in humid lowlands. From above they are covered with a thick layer of sphagnum (white moss), which has a very high moisture capacity. It reproduces well, as a rule, only where there is a layer of humus.
Under the layer of this vegetation are acidic, poor in water composition, with a very low oxygen content. Such conditions are absolutely unsuitable for the life of most living organisms, which include decay bacteria. Therefore, fallen trees, pollen of plants, various organic substances do not decompose, persisting for millennia.
Varieties
Sphagnum bogs may vary in appearance. Often they have a convex shape, because moss grows more intensely closer to the center, where the salinity of the water is especially low. On the periphery, the conditions for its reproduction are less favorable. Sometimes bogs are flat in shape. There are also forested and non-forested.
The former are characteristic of the eastern part of Europe and Siberia, where there is a pronounced continental climate. Treeless sphagnum bogs are found in more humid climatic conditions, which are more characteristic of the western regions of the European territory.
The origin of the sphagnum bog
It is established that the first swamps formed over 400 million years ago. The modern sphagnum peat bog is the result of a long evolution. After the ice age, water areas appeared, the main plants of which and peat-forming plants were grasses and mosses. The formation of peaty soils led to the formation of an acidic environment. As a result of the interaction of various geological and physical-geographical factors, swamping of land or the gradual overgrowing of water bodies occurred. Some of the marshes became uplands: their nutrition is completely associated with precipitation.
Sphagnum bogs are filled with water and look like lenses. Mineral salts are absent in the precipitation; therefore, such marshes are inhabited by plants adapted to lack of nutrition: mainly sphagnum mosses, grasses, and small shrubs.
Peat formation
Dead plant particles that accumulate annually in the sphagnum bog form rather large layers of organic matter. Gradually they turn into peat. Certain conditions influence this process: excessive moisture, low temperatures and an almost complete absence of oxygen. The remains of all dead plants are not destroyed, retaining their shape and even pollen. By studying peat samples, scientists can establish how the climate developed in this region, as well as how the change of forests occurred.
Sphagnum bogs store huge reserves of peat, which serves man as a fuel, therefore they are of great economic importance.
Sphagnum Moss
The dominant role in the vegetation of high bogs is played by sphagnum moss. It has a very peculiar structure. Kidney branches are located on the top of the stem, in the lower part - whorls of long branches located horizontally. The leaves are composed of various cells, some of which perform certain vital functions and contain chlorophyll. Other cells are empty, colorless and larger, are a container of moisture, which is absorbed like a sponge through many holes in the shell. They occupy ¾ of the entire surface of the sheet. Due to them, one part of the sphagnum is able to absorb water. Moss gives a good annual growth, in only one year it grows by 6-8 cm.
Other plants of sphagnum bogs
Only plants in which the rhizome is located vertically or slightly obliquely can grow on a moss carpet. This is mainly cotton grass, sedge, cloudberry, cranberries, as well as some shrubs, whose branches can give additional roots when the lower part begins to hide in the thickness of the moss. Such plants also include heather, rosemary, dwarf birch, etc. Cranberries spread along the surface of moss with long lashes, the sundew each year forms a rosette of leaves lying on the sphagnum carpet. There are also some herbaceous plants in Russia: sundew, pemphigus, sedge inhabits sphagnum bogs. In order not to be buried in the sphagnum, they all have the ability to move their growth point higher and higher. Most plants are stunted and have small evergreen leaves.
Of the tree species in the swamp, most often you can see a pine. Although it usually looks completely different than the one that grows on pine forest sands. The trunk of a tree growing on dry land, as a rule, is slender, thick. Swamp pine is stunted (no more than two meters high), clumsy. Its needles are short, and the cones are very small. In the cross section of a thin trunk you can see a large number of annual rings.
Trees inhabiting pine-sphagnum bogs do not have additional roots. Therefore, they are gradually overgrown with peat. Once at a great depth, the roots can no longer supply the leaves with enough moisture, as a result of which the pine tree withers and dies.
Human use of swamps
Bogs are of great value as sources of peat deposits used as fuel, as well as as a source of electricity for a number of power plants. In addition, peat is used in agriculture: it goes to fertilizers, bedding for livestock. In industry, insulating boards, various chemicals (methyl alcohol, paraffin, creosote, etc.) are made from it.
Of great economic importance are the upper sphagnum bogs, which are the main places for the growth of berry shrubs: cranberries, cloudberries, blueberries.
