Bog

A bog, or bogland, is a wetland biome that slowly accumulates peat, a soil made of dead plant material, most often mosses, that has only partly decomposed. Bogs draw most of their water from rainfall rather than from mineral-rich groundwater or surface water, which starves them of dissolved minerals and leaves them strongly acidic, a chemistry few plants can tolerate; sphagnum moss dominates where little else can grow, alongside hardy shrubs and specialized flowering plants, including carnivorous species such as sundews and pitcher plants that make up for the poor soil by digesting insects instead. The water flowing through a bog typically runs brown, colored by tannins dissolved out of the peat itself. Peat builds up only very slowly, because the low fertility and cool climate bogs typically favor keep plant growth slow, while the near-total lack of oxygen in the saturated soil keeps the dead plant matter from decaying much faster still, so a bog's peat layer can take centuries or millennia to reach any real depth, and that same slow decay makes bogs into long-term stores of carbon. They concentrate in the high latitudes of the Northern Hemisphere, though smaller areas exist south of the equator too; the peat bogs of the West Siberian Lowlands in Russia form the largest wetland on Earth, covering more than a million square kilometers, with substantial further areas across Canada and northern Europe.