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Glossary

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Acid bog

A bog is a waterlogged area of land. Underneath is peat - made up of dead plant matter – which is acidic. This also makes the water acidic and attracts particular plant species that are adapted to acidic conditions. Water flowing out of bogs has a characteristic brown colour, which comes from dissolved peat tannins. Bogs are very ecologically-sensitive habitats and are of high importance for biodiversity.

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Agrarian landscape

An area that is predominantly used for agriculture.

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Algal bloom

A rapid increase in the amount of algae in a water body such as a pond or river. Algal blooms are often green, but they can also be other colours such as yellow-brown or red depending on the species of algae. They are caused by an excess of nutrients in the water, particularly phosphorous from fertilizer used in farming. When the blooms die, the levels of oxygen in the water are significantly reduced and animals and plants may die off in large numbers.

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Alluvial soil

A fine-grained, fertile soil deposited by water flowing over flood plains or in river beds. Consists of clay, silt, sand and gravel sediments. Rich in nutrients so suitable for arable pastures.

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Alluvium

Loose, unconsolidated material typically made up of silt, clay, sand and gravel. It can be eroded, deposited and shaped by the movement of water or ice.

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Aquifer

An underground layer of permeable rock, from which groundwater can easily be extracted.

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Arable crop

A plant that is cultivated for food or other uses. Arable crops can be divided into several types including cereals (e.g. wheat, barley, oats, rye, maize, sorghum), oilseeds (e.g. soya beans, rape seed and sunflower seed) and legumes (e.g. peas, beans and lupins). 

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Arable farming

The cultivation of field crops.

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Arch (coastal)

A landform produced by coastal erosion. An arch forms when sea caves on opposite sides of a headland are eroded so deeply by crashing waves that the two caves eroding become joined. The overlying rocky roof is left as an arch. Whenthe arch collapses the seaward leg is left as a stack. The most well-known example of an arch on Britain’s coast is Durdle Door in Dorset.

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Area of Outstanding Natural Beauty

A designation given to areas of countryside in England, Wales and Northern Ireland that have significant landscape value. The primary purpose is to conserve and enhance the natural beauty of the landscape. The first AONB designation was awarded in 1956 and there are now almost 40.

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Avalanche chute

An avalanche is a sudden, rapid flow of snow down a slope. Where this occurs regularly in the same place, it can erode a pathway down a slope, which is known as a chute.

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Avocet

A type of wading bird found in wetlands such as salt marshes and mudflats. Their long, thin, upcurved bills are used to sweep from side to side when feeding. The species found in the UK is the pied avocet (Recurvirostra avosetta) and it is the emblem of the Royal Society for the Protection of Birds (RSPB).

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Sundew (drosera), a species specially adapted to bog conditions <br/> © Richard Webb, Geograph (Creative Commons Licence)

Sundew (drosera), a species specially adapted to bog conditions
© Richard Webb, Geograph (Creative Commons Licence)

A green algal bloom <br/> © Kenneth Allen, Geograph (Creative Commons Licence)

A green algal bloom
© Kenneth Allen, Geograph (Creative Commons Licence)

Wheat crop on arable land in Suffolk <br/> Rita Gardner © RGS-IBG Discovering Britain

Wheat crop on arable land in Suffolk
Rita Gardner © RGS-IBG Discovering Britain

Wheat field, County Durham <br/> Rory Walsh © RGS-IBG Discovering Britain

Wheat field, County Durham
Rory Walsh © RGS-IBG Discovering Britain

Langstone Rock coastal arch <br/> Jenny Lunn © RGS-IBG Discovering Britain

Langstone Rock coastal arch
Jenny Lunn © RGS-IBG Discovering Britain

The Cotswolds is the largest AONB in England and Wales <br/> Rory Walsh © RGS-IBG Discovering Britain

The Cotswolds is the largest AONB in England and Wales
Rory Walsh © RGS-IBG Discovering Britain

Avalanche chutes in The Manger <br/> © Pam Brophy, Geograph (Creative Commons License)

Avalanche chutes in The Manger
© Pam Brophy, Geograph (Creative Commons License)

Pied avocets <br/> Lip Kee Yap, Flickr (Creative Commons License)

Pied avocets
Lip Kee Yap, Flickr (Creative Commons License)