4.2 The nature and distribution of old environments Flashcards
How long did the Pleistocene era last?
From 1.8 million years ago to about 11,700 years ago.
What was the pattern of temperatures during this era?
An alternating pattern of cold periods (glacials) and warm periods (interglacials)
Where are most of the world’s cold environments?
Far north e.g. Scandinavia
what is the exception for some of the world’s cold environments?
Antarctica and South America
Latitude
east to west
longitude
north to south poles
Altitude
the distance of land from sea level
how many types of cold environments are there?
4
what are the four cold environments?
- Polar
- periglacial (tundra)
- Alpine
- Glacial
Describe the polar environment
- Areas of permanent ice
- essentially the vast ice sheets of Antarctica and Greenland
describe the periglacial environment
- Literally speaking at the edge of permanent ice
- Permanently frozen ground - Permafrost
- where: Northern Canada, Alaska, Russia, Scandinavia
Alpine
- High mountainous areas
- European Alps or New Zealand Alps
- High altitudes = cold conditions (especially in winter)
Glacial
- found in edges of the ice sheets
- particularly in mountainous regions such as the Himalayas and Andes.
what is the soil made up of in cold environments?
- a mixture of weathered rock
- rotted organic matter
- living organisms (biota)
- gases (particularly oxygen) and water
why is weathering limited in cold environments?
- lack of liquid water
why is the soil not very fertile?
- lack of vegetation
- little organic matter
- then there are few decomposers
- fungi and bacteria thrive in warm conditions
- due to these factors, soil formation s a painfully slow process, any soil that does develop is thin, acidic and frozen.
active layer
light grey unfrozen soil above the permafrost
- downward drainage is prevented by the permafrost which makes the active layer saturated and boggy
climate
all cold environments experience extreme cold temperatures. but tempt fluctuates
snowfall in polar regions
limited snowfall
snowfall in alpine environments
potentially huge amounts
what do frequent strong winds do?
- add to wind chill
- take away moisture from plants
how is the development of soil and vegetation as a result of cold environments?
- severe limiting effects on the development of soils and vegetation.
nutrient stores
- very limited in tundra environments
- transfer of nutrient flow is limited between components.
only sizeable transfer in the nutrient cycle
- fallout pathway:
- fallen leaves
- dead organic matter
both contribute to litter stores.
biodiversity in alpine regions
- alpine environments enjoy warm, wet summers providing good conditions for both soil formation and plant growth
- high alpine meadows can show great biodiversity in the summer.
temp to grow plants
6°
what do plants need to grow?
soil: to obtain nutrients ad water to grow
types of vegetation in periglacial environments?
- mosses
- lichens
- grasses
- sedges
- dwarf shrubs
