The Nature and distribution of cold environments Flashcards
Describe the characteristics of polar environments.
Above 60 degrees N/S of the equator.
4 to -28 degrees Celsius
Average precipitation/year = 100 mm
Describe the characteristics of alpine environments.
High relief - peaks >3,000 M above valley floor
Mostly in mountain ranges
-10 to 20 degrees Celsius
Describe the characteristics of glacial environments.
Areas that are currently covered by ice sheets/glaciers
10% of the land area of the earth is covered by ice
Describe the characteristics of periglacial environments.
High altitude dry areas - not permanently covered by snow and ice but cold enough for periglacial processes to happen
Permanently frozen ground - perrmafrost
Sparse vegetation
What are the main features of polar climate?
Below freezing all year
Winter = -50
Precipitation >150mm/year
Strong winds - over 200km/hr
What are the main features of tundra climate?
Long cold winters -20
Short mild summers, rarely above 5
At least 8 months where temperature is >0
Little precipitation - less than 300 mm/year
Strong winds - increases wind chill
What causes the climates of cold environments?
Low insulation levels
High albedo
High pressure system (frontal systems rarely penetrate the area, meaning low levels of precipitation)
Cool air (can only hold little amounts of water vapour)
Katabatic winds (Cold, dense air flows down valleys and off upland areas - more common inland and can be up to 200km/hr)
Describe the vegetation of the tundra.
Low level of productivity (short growing season of 50-60 days)
Less biological diversity
No fully grown trees - dwarf trees
Flowering plants are perennials - flower year after year and hardy seeds
Soils are waterlogged because thawed water cannot get past impenetrable permafrost
Low evaporation levels
What are the types of plants in a tundra?
Lichens (can colonise bare areas and have no roots - can absorb water and nutrients directly into foliage)
Moss (with lichens - initiates soil formation)
Grass
Cushion plants
Low shrubs
How have plants adapted to the conditions of a tundra?
Ground hugging to avoid the cold - avoids winds and takes advantage of any warmth from the ground
Slow growth
Shallow roots because of permafrost
Can photosynthesise at low temperatures - even under thin snow
Reduced transpiration due to small leaves and thick cuticle
Low albedo of plant surfaces - can absorb more radiation
Perennial - can store food from year to year
What is the soil of a tundra like?
No clear soil horizons/layers
Thin surface organic layer - very acidic
Waterlogged in the summer
Gleyed - the waterlogging iron compounds are reduced to their ferrous form - grey/blue colour
Slow rate of decay due to few soil organisms and the cold temperatures - limited organic matter
