Cold Environments (AQA GCSE Geography)

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Characteristics of Cold Environments

There are two main categories of cold environments:
- Polar environments which include Antarctica and parts of the Arctic (Greenland, northern Russia and Canada)
  - Coldest places on Earth
  - Located within the Arctic and Antarctic circle (from 66.5° to 90° N and S)
- Tundra environments are found mainly in the northern hemisphere
  - Lack permanent ice cover, but experience freezing temperatures most of the year
  - Have a layer of permafrost beneath the active soil layer
  - Found mostly in the northern hemisphere between the taiga and coniferous forests at 60° N and the polar environment
  - Most of Antarctica is too dry and cold to support tundra vegetation but South Georgia and the Antarctic Peninsula have some tundra environments
Both are fragile and easily damaged
Together they make up approximately 35% of the Earth and are found at the higher latitudes
Cold environments are only above freezing for 3 months a year
At the upper latitudes, the sun does not rise or sink for several months of the year

Characteristics of Cold Environments

	Tundra	Polar
Climate	Temperatures range from -50°C in winter to 10°C in summer (average is between -6°C and -12°C) Permanent darkness in winter and permanent sunlight in summer Precipitation is low with less than 380mm Clearly defined seasons	Temperatures very rarely rise above 0°C with winter temperatures plummeting to -40°C and below Precipitation is low with no more than 100mm per year Winters are long, cold and windy Icecaps permanently cover polar regions Clearly defined seasons of cold summers and even colder winters
Soil	Thin, acidic soil and not very fertile Has a layer of permafrost (up to 450m) below the active soil layer containing large amounts of trapped methane, a greenhouse gas	Polar regions have little or no soil as they are covered by ice sheets
Plants	No trees due to permafrost, but some small, short trees grow in warmer, sheltered areas Vegetation growth is slow and low Grasses are the most common with mosses and lichens Any flowering plants have a rapid life cycle and are very bright to attract insects	Very few plants but some lichens and mosses are found on rocks Warmer coastal regions of Antarctica may see a few grasses
Animals	Diversity is low but not as low as polar regions Polar bears, wolves, caribou/reindeer, snow geese and arctic foxes and hares are common Goats and sheep live in mountainous areas In summer, insects, birds and other wildlife emerge as the active soil layer melts	Diversity is very low Penguins in the Antarctic and polar bears in the Arctic Snowy owls, whales, seals and walrus
People	Largely inhabited Large indigenous populations Oil and gas workers in the larger towns and cities	Almost uninhabited Scientific research for part of the year in Antarctica Indigenous people live in some Arctic regions

Interdependence in Cold Environments

The living (biotic) and non-living (abiotic) in cold environments are closely linked
If one component changes, the others are affected
They are 'inter-dependent' on each other for survival
The low biodiversity of the cold, dry climate means this interdependence is fragile and easily disrupted or damaged
- If temperatures increase (e.g. due to global warming) more sea ice melts in the summer
- Animals such as seals and polar bears rely on sea ice for breeding and hunting
- So, if it disappears these animals are threatened
Other examples of interdependence include:
- Antarctica has very few plants, making phytoplankton in the sea the most important producers and form the basis of the food chain
  - Phytoplankton > krill > fish > penguins
  - Phytoplankton rely on the nutrient-rich sea currents rising to the surface from deep waters
  - If this didn't happen the whole ecosystem could collapse
- Plant cover is low causing plants to grow slowly but also to decompose slowly
- This makes the soil low in nutrients, further reducing the ability of further growth
- Herbivores, like reindeer, rely on plants like mosses to survive, but they also provide nutrients to the soil through their dung, from eating the plants
- Plants also rely on herbivores to help them reproduce as animals spread seeds through their dung and on their fur
- Carnivores, like wolves, will follow the herbivores as they search for vegetation
The tundra in summer, has greater plant cover, allowing surface plants to absorb heat from the sun and preventing the permafrost below from thawing
The permafrost provides water and diluted nutrients for plants and any damage to the permafrost will cause it to melt, leading to flooding and stopping plant growth
It also releases trapped greenhouse gases (methane) – leading to increased global warming, and changes to the climate of cold environment, threatening plants and animals as a cycle

Plant & Animal Adaptations

The tundra biome has about 400 varieties of flowers but only 48 different animals
Plants in the tundra need to adapt to wet summers and dry winters:
- Summer: Top layer of soil thaws producing boggy and waterlogged land
- Winter: Frozen soil and long, dark winters
Animals need to adapt to cold, dry, snowy conditions, as well as wet summers

Adaptations of Animals and Plants to Cold Environments

Animal	Plant
Some animals hibernate to conserve energy and survive the winter, e.g. Arctic ground squirrels hibernate for 7-8 months of the year and can survive even if their body temperature drops below freezing.	Most plants become dormant to survive the cold, dark winters
Animals are well-insulated e.g. thick fur like polar bears or blubber like seals. This reduces the amount of energy they have to use to keep warm.	Plants are small and round-shaped to provide protection from the wind.
Many birds migrate to warmer area during winter – Arctic terns live in the Arctic during the northern hemisphere summer then fly to the Antarctic for the southern hemisphere summer.	Most plants have shallow roots because the permafrost prevents any further growth. Leaves are generally small, and this limits moisture loss. The Caribou Moss has hollow stems and will become dormant until next rainfall.
Many animals have white coats in winter for camouflage – this helps predators sneak up on prey, and for prey to hide in the snow. Arctic hares are white, this makes them harder for predators to spot against the snow.	The warmer, wetter summer is very short, so most plants have adapted to a growing season of just 50-60 days. They are very bright and vibrant to attract as many insects as possible for pollination.
Many animals have physical adaptations, such as short legs: round, squat bodies: layers of fur and insulating blubber. The Musk Ox grows two layers of fur. Warm air is trapped in the shorter layer. The longer layer is over 60cm long. Its hooves are large and hard, allowing to break the ice and drink the water beneath.	Many plants use underground runners or bulbs instead of seeds to reproduce because the growing season is so short.

Biodiversity Issues

Adaptation takes time, but changes to an ecosystem can be fast
Cold environments have very low biodiversity (particularly Antarctica)
Low biodiversity means when the population of one species changes it can affect the population of dependent species – e.g. changes in the number of Arctic hares affect the number of Arctic foxes (their predators)
Global warming is causing some species to move towards the poles, where it is cooler to cope with temperature rises elsewhere
Those species that have already adapted, such as the polar bear, have nowhere else to go and are at risk of extinction

Worked example

Outline one way that plants are adapted to the climate in cold environments.

[2 marks]

You will gain credit about one environment only
Max 1 mark for two separate points
No marks will be given for referring to animal adaptation
Responses need to be developed (d):

Answer:

E.g. Most plants become dormant [1] to survive the cold, dark winters (d) [1] Plants are small/round-shaped [1] to provide protection from the wind (d) [1]
Most plants have shallow roots [1] because of the layer of permafrost/ice beneath the soil layer (d) [1]. Leaves are generally small [1] to limit the amount of moisture lost (d) [1].
Many plants use underground runners or bulbs instead of seeds [1] because the growing season is so short (d) [1]

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