Characteristics of Cold Environments (AQA A Level Geography)

Physical Characteristics of Cold Environments

Polar 

• Climate

  • Harsh, covered in snow and ice

  • Long winters and short summers 

  • Snow storms and cold winds for most of the year

  • The Arctic's mean temperature range is -28°C to 4°C

  • Average annual precipitation of approx. 100mm

  • The Antarctic's mean temperature is -55°C in places

  • Coastal areas are milder with an annual average of -10°C

  • Annual average precipitation is 200mm

• Soil

  • Where land is ice-free, the soil is thin, acidic and infertile

  • Lacks nitrogen and carbon due to low decomposition rates

• Vegetation

  • Limited liquid water slows growth and species diversity

  • Mosses and lichens are able to survive in some areas

    • The roots of these plants secrete an acid that dissolves rock

    • In this way, they gain nutrients from the rock they are attached to

Alpine 

• Climate

  • Cool climates with some snow coverage but not all year

  • Seasonal temperatures range from −10°C in winter to 20°C in the summer months

  • Precipitation in alpine mountains depends on aspect

    • Windward sides receive large amounts of precipitation; with snow in the winter months

    • Leeward sides are in the rain shadow and therefore, drier and protected from strong winds

• Soil

  • Where land is ice-free, soil is thin, acidic, gravelly and infertile

  • Lacks nitrogen and carbon due to low decomposition rates

• Vegetation

  • Lack of liquid water limits growth and species diversity

  • Low-lying shrubs and mosses and lichens thrive at the highest altitude

Glacial

• Climate

  • Characterised by permanently low temperatures, but may rise above 0°C with seasonal temperature variations 

  • Cold climates in high latitudes and altitude

  • Ice remains throughout the year

  • High precipitation, but limited liquid precipitation, provides inputs into the glacial system

  • Little seasonal temperature variation 

• Soil

  • Glacial soil is rocky, and thin, with ice blocks and infertile

  • The soil exposure is less due to snow cover

• Vegetation

  • Limited growth and species diversity due to ice and snow cover and lack of liquid water

  • Mostly mosses and lichens 

Periglacial

• Climate

  • Cool climates with some snow coverage but not all year

  • Seasonal temperatures range from −10°C in winter to 20°C in the summer months

  • Mean average temperature between -1°C and -3°C

  • Precipitation in alpine mountains depend on aspect

    • Windward sides receive large amounts of precipitation; with snow in winter months

    • Leeward sides are in the rain shadow and therefore, drier and protected from strong winds

    • Mean annual precipitation less than 1000mm

• Soil

  • Most of the soil is permafrost with some regions seeing seasonal melting creating an 'active layer' for growth

  • Where there is seasonal melting, the soils become deeper with peaty, un-decomposed vegetation and frost-shattered rock 

  • They are a good source of carbon and methane sequestering

  • The potential of these soils is significant in forecasting global temperatures in the future

  • Occasionally, unfrozen soil is found within the permafrost called talik

  • Talik is thought to form when latent heat is released as the active layer re-freezes

• Vegetation

  • Limited growth and species diversity due to permafrost and intermittent liquid water

  • Mosses, lichens and small shrubs of birch and willow 

  • Where meltwater is available and soil depth sufficient, growth and species diversity increases

  • Low-growing plants have small, waxy leaves designed to retain warmth and reduce transpiration through wind exposure

  • During the short summer months, they flower and set seed in just a few weeks and are brightly coloured to attract as many insects as possible

Periglacial Nutrient Cycling

• Climate limits interaction between soils and vegetation  

• All stores are small; indicating that the availability of nutrients is limited

• Transfer of nutrients between stores is generally limited and slow

• Inputs from precipitation and weathering are greater than runoff and leaching (increasing the size of the environment)

• Uptake of nutrients from the soil is slow due to climate and limited vegetation

• Transfer between biomass and litter (fallout pathway) is the largest and fastest in periglacial environments

  • Occurs through dead organic matter such as leaves and animals 

• The decay pathway is the slowest due to the cold climate restricting detritivores and decomposition