Why bogs are acidic

Sphagnum moss. Pitcher plant. Fringed gentian. Marshes Sedge meadows Forested wetlands Shrub thickets Rare wetlands. Like bogs, they get most of their moisture from precipitation. Evergreen plants like loblolly pine, holly, bay and pond pine are common in pocosins. The venus flytrap can also be found in the pocosin. Animals in pocosins include lots of species of reptiles, amphibians and rodents as well as black bears, bobcats , bats, white-tailed deer , opossums , raccoons , river otters, mink , muskrats , northern bobwhites, and American woodcocks.

Pocosins are very vulnerable to fire when they are dry. Pocosin is an Algonquin word that means " swamp on a hill. Bogs, Fens and Pocosins Bogs Bogs are mossy wetlands. Pocosins Pocosins are evergreen shrub bogs found on the coastal plains of the southeastern United States from Virginia to Florida. Like bogs, fens formed when glaciers retreated.

Grasses and sedges are common plants in fens and fens often look like meadows. A bog is formed when a lake slowly fills with plant debris. Sphagnum moss , as well as other plants, grow out from the lake's edge. The vegetation eventually covers the lake's entire surface. Bogs can also form when the sphagnum moss covers dry land and prevents precipitation from evaporating.

These bogs are called ombrotrophic bogs. Plants decay slowly in bogs, because flooding prevents a healthy flow of oxygen from the atmosphere. Bog soils are oxygen- and nutrient -poor, and are much more acid ic than other soils. Eventually, watery bogs become choked with living and decaying plants.

These slowly decaying plants become the main components of the bog's soggy soil, called histosol. Fungi and low-lying shrubs, such as heather, grow in histosol. Heather can grow directly on sphagnum moss. In fact, bogs are often called "heaths" after the abundance of heather that blankets them. Peatlands Thick, spongy layers of histosol eventually form peat. Peat is a fossil fuel that is the first stage in the long process of plant material turning into coal. Ancient bog plants, mostly sphagnum moss, are the fossils in peat.

People have harvested peat for thousands of years. It is a source of energy for heating, insulation , and electricity throughout northern Europe. Thousands of bogs throughout Ireland, Scotland, Scandinavia, and Russia have been drained for peat excavation. Thick blocks of peat are cut and allowed to dry. The blocks are then burned. In some places, such as Ireland, peat is an industrial fuel for electricity and heating. In places like Scotland or Scandinavia, individuals or communities harvest peat for use as a cooking fuel.

Tropical peatlands, located mostly in southeast Asia, are sources of valuable timber. They are also popular sites to drain for development.

Dried peat is also used in agriculture. Peat, sometimes called "peat moss," increases soil's ability to retain water. Bog Ecology Bogs are ecologically important because they absorb great amounts of precipitation. They prevent flooding and absorb runoff. Sphagnum moss, reeds, sedges, and heather are common bog plants. Bogs that receive all their water from precipitation not lakes, glaciers or groundwater are ombrotrophic.

Ombrotrophic bogs have very few nutrients, making it difficult for many common plants to survive. Carnivorous plants have adapted to ombrotrophic environments by not absorbing nutrients from the surrounding water, but from insect prey.

These carnivorous plants, such as sundews and pitcher plants, trap insects and dissolve them for nutrients. Bogs that are fed by lake basins and other water sources have even more biodiversity. Plants that grow in these bogs include cranberries, blueberries, and huckleberries. Insects thrive in muddy bogs and consume plants, fungi, and pollen. Many bog insects, such as the hairy canary fly, do not live in any other ecosystem. Plant community composition is partly determined by the acidity of peat bogs and can change in response to increasing levels of mineral acidity.

In the absence of a protective cuticle, lichens readily absorb rainfall of any pH making them highly vulnerable to acid deposition. Physiological processes are also pH sensitive. Establishing the nature and extent of anthropogenic impact relative to the natural acidity of these ecosystems can be challenging see Wilson et al, Acid deposition effects on bog vegetation and the underlying peat are very closely coupled - the characteristics of the vegetation predetermine those of the peat and should always be considered together.

Impacts have been observed on the functioning of peat ecosystems, e. Acid deposition has caused a decline in peat pH and drainage waters. The natural pH of Scottish peats has declined by about 0. Peats with highest acidity and lowest base saturation tend to occur in areas where atmospheric deposition is highest Skiba et al.

Soil pH affects directly the kind, density and the activity of fungi, bacteria and actinomycetes involved in decomposition. But, decomposition does not depend on a few species, rather, a consortium of organisms are involved, with complementary enzymatic activities Andersen et al However, whether or not acidity restricts decomposition or slows it down is more difficult to establish.

Also apart from locking up essential growth nutrients retarding decomposition on bogs would be a benefit in terms of carbon sequestration. What is known is that the composition of the decomposer community will change however, with acidity favouring fungi over bacteria Rousk et al The bacterial community composition and diversity reflects and responds strongly to soil pH Hartman et al , especially the methanogenic community.

Rain-fed bogs acquire all their nutrients and water from the atmosphere, making them extremely vulnerable to the effects of atmospheric pollutants Thompson and Bottrell, Hydrology is the most important determinant of the quality of peat bog ecosystems and the level of the water-table also affects acidity, via effects on the redox potential and the form in which ions occur in solution: this can influence the toxicity of metal cations e.