Cold environments

• Cold Environments


  Polar and Tundra
• Polar areas


  • Very cold, normally below freezing
  • Winters tend to drop to -40 °C and can reach -90 °C
• Tundra areas


  • Also cold
  • Warm months only reach a maximum of 10 °C
  • Winters can plunge to -50 °C
• Precipitation in polar areas

  • Less than 100 mm a year
• Precipitation in tundra areas

  • Less than 380 mm a year
• Seasons in polar and tundra environments

  • Well defined - cold summers and even colder winters
• Polar soil

  • Ice sheets cover polar areas, so no soil is exposed
• Tundra soil


  • Thin, acidic and not very fertile
  • Beneath the thin soil is a layer of permafrost - frozen ground, holding trapped greenhouse gases
• Polar plants


  • Few plants - lichens and mosses grow on rocks, and grasses grow on the coast
• Tundra plants


  • Hardy shrubs (e.g. bearberry), grasses, mosses and lichens are common
  • Small, short trees may grow in warmer areas
• Polar areas


  • Mostly uninhabited, but the Arctic has some indigenous residents and a few scientists work in Antarctica
• Tundra areas


  • Home to many indigenous people, as well as oil and gas workers in larger towns
• Polar animals


  • Relatively few species
  • Polar bears, penguins, whales and seals are found
• Tundra animals


  • Lemmings, wolves and reindeer live
• Cold environments are fragile, interdependent ecosystems
• The biotic (living) components and the abiotic (non-living) components are closely related - many of them are dependent on each other
• The cold climate causes plants to grow slowly and to decompose slowly when they die, so plant cover is low
• The soil is relatively low in nutrients, further limiting plant growth
• Herbivores (e.g. reindeer) that rely on plants (e.g. mosses) to survive must migrate to areas where plants are able to grow
• Carnivores (e.g. wolves) have to follow the herbivores
• In summer, when the tundra has greater plant cover, the surface plants absorb heat from the sun, preventing the permafrost below from thawing
• The permafrost provides water for plants
• Changes to one component of the ecosystem can have knock-on effects on the whole ecosystem
• If humans trample lots of plants, the soil is exposed to sunlight and warms up
• This may thaw the natural permafrost, releasing trapped greenhouse gases and preventing plant growth
• With fewer plants, herbivores have less to eat and may struggle to survive
• Plants in cold environments

  • Low-growing and round-shaped to provide protection from the wind
  • Shallow roots because of the layer of permafrost beneath the soil layer
  • Small leaves to limit the amount of moisture lost through transpiration
  • Short growing season of just 50-60 days
  • Reproduce using underground runners or bulbs to cope with the cold and short growing season
• Animals in cold environments

  • Well-insulated with thick fur or a layer of blubber to reduce energy use for keeping warm
  • Some hibernate to conserve energy and survive the winter
  • Adapted to survive on limited food sources available
  • Many migrate to warmer areas for the winter
• Animals in cold environments

  • Grow white winter coats for camouflage
• Cold environments have low biodiversity, particularly Antarctica
• Low biodiversity means when the population of one species changes it can affect the population of dependent species
• Climate change is causing some species to move towards the poles, where it is colder, in response to temperature rises in their natural habitat
• Species already adapted to polar environments can't go anywhere colder, so are at risk of decline
• Wilderness areas


  Wild, natural environments that are undeveloped, uninhabited and undisturbed
• Importance of conserving wilderness areas in cold environments

  • Provide habitats for organisms that couldn't survive elsewhere
  • Scientists can study natural environments including landforms, plants and animals that are relatively unaffected by people
  • Studying natural ecosystems may help scientists to replicate the same conditions in managed ecosystems to help preserve rare species
• Cold environments are extremely fragile and can take centuries to recover from human interference
• Plant growth is slow, so regrowth takes time if plants are damaged
• Species are highly specialised, so find it difficult to adapt to change
• Polar bears are adapted to hunt on ice, but their numbers are decreasing as sea ice melts earlier each year
• International agreements to protect cold environments

  • The 1959 Antarctic Treaty limits visitors and activities to protect the fragile ecosystem