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Earth’s life support systems - Arctic tundra - Coggle Diagram
Earth’s life support systems - Arctic tundra
Location
Occupies 8 million km2 in northern Canada, Alaska and Siberia (extends from Northern edge of the boreal coniferous forest to Arctic Ocean)
Climate
Severe: become extreme with latitude
For 8-9 months a year, tundra has temps below dressing - ground permanently frozen with only the top metre or so thawing in arctic summer
The water cycle in the arctic tundra
Low annual precipitation (50 to 350mm) with most precipitation being snow
Limited transpiration due to minimal vegetation
Small store of moisture in atmosphere due to low temperatures, reducing absolute humidity
Limited groundwater and moisture stores because permafrost acts as a barrier
Minimal transpiration
Permafrost
Permanently frozen soil/ground
A thick layer of soil that remains below freezing point throughout all seasons
Growing season
The period of time each year when it is warm and wet enough for plants to grow
The growing season is in the summer for the actric tundra area
The carbon cycle in the Arctic Tundra
Permafrost here is a vast carbon sink (estimated to contain 1600 GT of carbon )
Accumulation of carbon is slow due to low temperatures slowing down decomposition of plant material
Carbon flux is concentrated in summer months where plants grow rapidly in the short summer with longer daylight hours but the tundra biomass is still small with less than 200g/m/year NPP
Once permafrost works as a carbon sink, concerns over global warming resulted in it becoming a carbon source with carbon outputs increasing in recent years
Physical and seasonal factors affecting flows and stores in the water cycle in the arctic tundra
Liquid water: surface run off and precipitation are main input to liquid water stores
Human factors affecting the water cycle
Oil and gas exploration have increased melting of snow cover an permafrost, so flooding is more likely
Human factors affecting the carbon cycle
Oil and gas exploration melts permafrost, releasing stored carbon
Melting caused by:
building for the oil and gas industry
deposition of dust along roads so ice and snow absorb more sunlight
removal of vegetation which previously insulated the permafrost
Gas flaring and oil spills put co2 directly into the atmosphere
Strategies to manage change in the water and carbon cycles
Infrastructure built on gravel pads protects permafrost from melting
Buildings and pipelines built on piles allowing cold air to circulate, stopping melting of permafrost
Refrigerated supports of Trans-Alaskan pipeline, buildings and infrastructure stabilise permafrost temperatures