bog

thumb|250px|A bog in Lauhanvuori National Park, [[Isojoki, Finland]] thumb|250px|Peat bog and peat to dry, L'Isle-aux-Coudres#Geography|L'Isle-aux-Coudres, [[Quebec, Canada, 1976]] thumb|Bog in Antwerp Province, Belgium thumb|Bog in the Seliger Lake area, Tver Oblast, Russia thumb|Peat extraction in East Frisia, Germany thumb|Drone video of Kakerdaja bog in Estonia (September 2021) thumb|A raised bog in [[Ķemeri National Park, Jūrmala, Latvia, formed approximately 10,000 years ago in the postglacial period and now a tourist attraction.]] A bog or bogland is a wetland that accumulates peat as a deposit of dead plant materials often mosses, typically sphagnum moss. It is one of the four main types of wetlands. Other names for bogs include mire, mosses, quagmire, and muskeg; alkaline mires are called fens. A bayhead is another type of bog found in the forest of the Gulf Coast states in the United States. They are often covered in heath or heather shrubs rooted in the sphagnum moss and peat. The gradual accumulation of decayed plant material in a bog functions as a carbon sink.

Bogs occur where the water at the ground surface is acidic and low in nutrients. A bog usually is found at a freshwater soft spongy ground that is made up of decayed plant matter which is known as peat. They are generally found in cooler northern climates and are formed in poorly draining lake basins. In contrast to fens, they derive most of their water from precipitation rather than mineral-rich ground or surface water. Water flowing out of bogs has a characteristic brown colour, which comes from dissolved peat tannins. In general, the low fertility and cool climate result in relatively slow plant growth, but decay is even slower due to low oxygen levels in saturated bog soils. Hence, peat accumulates. Large areas of the landscape can be covered many meters deep in peat.