page_title: Raised bog
section_title: Polygonal bogs
hierarchical_section_title: Raised bog / Types and distribution / Polygonal bogs
context_page_description: Raised bogs, also called ombrotrophic bogs, are acidic, wet habitats that are poor in mineral salts and are home to flora and fauna that can cope with such extreme conditions. Raised bogs, unlike fens, are exclusively fed by precipitation and from mineral salts introduced from the air. They thus represent a special type of bog, hydrologically, ecologically and in terms of their development history, in which the growth of peat mosses over centuries or millennia plays a decisive role. They also differ in character from blanket bogs which are much thinner and occur in wetter, cloudier climatic zones.
  Raised bogs are very threatened by peat cutting and pollution by mineral salts from the surrounding land. The last great raised bog regions are found in western Siberia and Canada.
context_section_description: Polygonal bogs (Polygonmoore) are widespread on the Arctic and sub-Arctic plains of Siberia and North America and cover vast areas. They are associated with patterned peatland and ice wedges. A scanty layer of peat-forming vegetation can occur in the inner honeycomb-shaped areas of this frost pattern terrain (cryoturbation) and are fed during the short summers with sufficient moisture, because the meltwater is prevented from draining away by the raised polygonal margins. The peat layers can attain a thickness of 0.3 to 1 m (1.0–3.3 ft).
caption: A polygonal bog comprising flat ponds with the characteristic polygonal structure
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