L10 + 11 An intro to cold environments

• tundra climates are found south of the ice caps in the northern hemisphere
• tundra climates occupy around 1/5 of the earths land surface and lack permanent ice cover however experience very cold weather most of the year
• in tundra climates, most of the ground is completely frozen and vegetation is low-lying shrubs.
• tundra climate areas include Russia and Canada
• polar climates are found in inland areas, far away from the warming influence of the sea
• polar climates include Russia, greenland, North Canada and antarctica
• in polar climates, snow and ice accumulate over time and most polar regions are partly or fully covered with ice caps
• in polar climates, precipitation falls mostly as snow, with little precipitation
• in tundra climates, precipitation falls as snow in winter and as rain during the brief summer
• in cold environment, most of the ground is permanently frozen. this is called permafrost
• around a quarter of the earths surface is affected by continuous or sporadic permafrost, including tundra, polar and some mountain regions
• in tundra regions, ice in the uppermost active area of the soil thaws for one or two months of the year during the brief summer, but there is still ice beneath the active layer
• the ice acts as an impermeable barrier to the downward movement of melted water in the soil layer above. this results in waterlogged conditions
• poor drainage in the tundra:

  in the flat, low lying tundra regions, summer melting of the active layer leaves many areas waterlogged. this favours hardy organisms like masses that can tolerate both extremely dry and wet conditions
• low insulation in the tundra:

  due to the high latitude of the tundra, light is weak even with long summer days. snow covers plants for many months of the year and they have therefore adapted in ways that maximise photosynthesis during the short growing season.
• low insulation in the tundra:

  most tundra shrubs are perennials. as a result, photosynthesis can begin immediately because the plants do not need time to regrow their leaves
• strong winds in the tundra:

  high air pressure over the north pole creates strong, cold winds that blast tiny particles of ice southwards over the tundra. plants have adapted in ways that keep them warm and minimise transpiration loss to the wind. they grow close together and low to the ground, their leaves are small and fringed and seeds have wooly covers
• soils and nutrients in the polar and tundra areas:

  in tundra regions, ice in the uppermost active layer of the soil thaws for one or two months of the year, but there is still ice below the active layer.
• soils and nutrients in the polar and tundra areas:

  plants form shallow roots to keep them from freezing over, they store nutrients over the winter to allow rapid growth in the summer, in polar regions, small plants and shallow root systems compensate for the thin layer of soil. many arctic species can grow under a layer of snow and photosynthesise in extremely cold temperatures. plants gather nutrients from the sun in the summer months
• the biotic and abiotic components of ecosystems have become interdependent, largely through necessity. the overall biodiversity is so low that they are all reliant on each other
• some species only live in the the tundra regions during the warmer, summer months and migrate elsewhere in winter
• permanent residents such as the tundra birds and small mammals, use moss to line their nests for warmth against the icy winds
• traditionally, the inupiat people of the arctic circle depend on animal skin and feathers for their clothing to protect them in harsh weather.
• historically, indigenous people in coastal areas have depended on marine species such as fish, sharks and whales for food and tools