Cold Environments

• Cold Environments


  • There are two main categories: Polar environments (Antarctica, Arctic) and Tundra environments (northern hemisphere)
  • 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
• Polar environments


  Coldest places on Earth, located within the Arctic and Antarctic circle (from 66.5° to 90° N and S), permanently covered by ice sheets
• Tundra environments


  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
• Characteristics of Cold Environments

  • Tundra: 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
  • Polar: 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 in Cold Environments

  • Tundra: 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: Little or no soil as they are covered by ice sheets
• Vegetation in Cold Environments

  • Tundra: 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
  • Polar regions: Most of Antarctica is too dry and cold to support tundra vegetation but South Georgia and the Antarctic Peninsula have some tundra environments
• Cold environments are fragile and easily damaged
• Tundra


  Cold environment
• Polar


  Cold environment
• Climate of cold environments

  • 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 in cold environments


  • 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
• Polar regions


  • Icecaps permanently cover polar regions
  • Clearly defined seasons of cold summers and even colder winters
• Soil in cold environments

  • 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 in cold environments

  • 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 in cold environments

  • 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 in cold environments

  • Largely inhabited with large indigenous populations and oil and gas workers in the larger towns and cities
  • Almost uninhabited except for 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
• Antarctica has very few plants

  Phytoplankton in the sea is the most important producer and forms the basis of the food chain
• Phytoplankton


  Rely on the nutrient-rich sea currents rising to the surface from deep waters
• If the nutrient-rich sea currents didn't happen


  The whole ecosystem could collapse
• Plant cover is low

  Plants grow slowly but also 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
• Damage to the permafrost


  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
• Adaptations of plants in cold environments

  • Most plants become dormant to survive the cold, dark winters
  • Plants are small and round-shaped to provide protection from the wind
  • 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
  • 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 plants use underground runners or bulbs instead of seeds to reproduce because the growing season is so short
• Adaptations of animals in cold environments

  • 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
  • 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
  • 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
  • Many animals have white coats in winter for camouflage – this helps predators sneak up on prey, and for prey to hide in the snow
  • 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
• 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