Artic tundra and Alaska Flashcards
What underlies much of the tundra
Permafrost
How does the temperature of the tundra change with seasons
Summer months above freezing but rest is way below (can reach up to minus 40)
What are the main features of the water cycle in tundra
Low annual precipitation
Small atmospheric store of water
Limited transpiration (seasons)
Low evaporation
Limited groundwater and moisture stores
Accumulation of snow and ice during the winter
Extensive wetlands, ponds and lakes in the summer
Carbon cycle in the tundra
Permafrost is a vast sink (methane) Slow decomposition (due to temperature) Plants grow rapidly in the short summer
What is the productivity of tundra regions like
Poor
What are the problems associated with oil and gas production in Alaska (climate)
Harsh climate
The huge variations in temperature would cause the pipe to expand and contract
What was the solution to relieve the contraction and expansion of the pipe
Zig-zag configuration
What was the problem with the area that the oil and gas are in
Remoteness
The waters of prudhoe bay freeze so no tankers
What is the area prone to
Earthquakes
How did they solve the problems of the earthquakes
Pipe built on slider beams to allow for lateral movement
What are the problems with the ecosystem in Alaska
Fragile ecosystem (few links)
What was the problem with the permafrost for the pipe
It couldn’t be buried because the oil would melt the ice causing the pipe to sag
The freeze-thaw cycle would damage the pipeline
How did they solve the permafrost problems
Built the pipe line above ground
Refrigeration posts
Tapped in fibreglass insulation
Why did they build the pipeline
High global energy prices
US governments policy to reduce dependance on oil imports
War in the middle east
What impact does the pipeline have on the water and carbon cycle
Oil and gas exploration had impact on the permafrost and local water and carbon cycles
Damages ecosystem
Can upset the volume in stores
What are the management stratagies
Protect permafrost
Insulated ice and gravel pads
Buildings and pipelines elevated on piles
Drilling laterally beyond drilling platforms
Refrigerated supports
How much and where does it occupy?
8 million km2 in North Canada, Alaska and Siberia.
How long does it have a negative heat balance?
8-9 months.
What Is the biodiversity like in the south compared with the north
In the south vegetation covers all surfaces but in the north it becomes incontinuous.
What is the annual precipitation?
50-350 mm- vey low and mostly snow
Why is the atmosphere a small store of water
Very low temps reducing humidity.
Why is there low rates of evaporation?
Sun’s energy is used to melt the snow so ground temp is low and inhibits convection
What can permafrost cause?
Blockages of drainage creating extended wetlands,ponds and lakes in the summer.
Where and when were oil and gas discovered?
Prudhoe Bay (north slope of Alaska, between Brooks Range and Arctic Ocean) in 1968.
What were some severe challenges for development?
Harsh climate, darkness in winter,permafrost, melting of active layer, remoteness, poor accessibility and fragile ecosystem.
Why did development continue despite challenges?
USA’s policy to reduce oil imports and high global prices.
What years did the completion of pipelines,roads,power lines and oil plants occur?
1960s and 1970s.
By the 1990s how much of the USA’s oil did the North Slope account for?
nearly a quarter.
How much of the USA’s oil does the North Slope account for today and why?
Only 6% due to high production costs and massive growth of oil shale industry in USA.
What has caused local melting of fragile permafrost?
Oil plants diffuse heat directly to surroundings.
Dust deposition causes the surface of snow to darken.
Removal of vegetation cover which insulates
permafrost.
What does permafrost release?
CO2 and CH4
What else inputs carbon into the atmosphere?
Gas flaring and oil spillages.
What does the destruction of vegetation from industrial development cause?
less photosynthesis,thawing of soil increasing microbial activity and increasing rate of decomposition-more CO2 released.
What does the slow growing nature mean for the rate of recovery?
It takes decades to recover from damage.
What does increased run off from melting of permafrost cause?
Increased flooding so increased river discharge.
What does more extensive wetlands and lakes cause?
More evaportation.`
What does strip mining of aggregates create and disrupt?
Artificial lakes and disrupts natural drainage networks and exposes permafrost.
What causes drainage networks to be disrupted?
from construction of roads and seismic explosions used to prospect for oil and gas
What causes reduction in localised run-off?
Water taken from rivers for industrial use and to build ice roads in winter.
what is the main store of water
Ice in permafrost as temps are below freezing for most of the year.
Why Is drainage poor?
Permafrost as cannot infiltrate soil.
What does low temps inhibit in the winter?
Evaporatranspiration but some occurs in the summer from standing water, saturated soils and vegetation.
Why is permeability low?
Permafrost and crystalline rocks which are
the main geology of the area and there’s is a very gentle gradient.
What is the main carbon store?
Decomposed plant material in permafrost that has been there for 500,000 yrs.
Why is there little photosynthesis and NPP?
There is little biomass from slow plant growth and little water in liquid form.
What can low temps and waterrlogging cause?
slow decomposition and respiration.
Why does rock have little influence on the carbon cycle?
Due to permafrost and geology’s impermeability, porosity and mineral composition of rock (not much carbon).
What is the main goal?
To stop meliting of permafrost as it is an imporant carbon sink and to prevent damage to building the melting causes.
What are insulated gravel and ice pads for?
So roads and other infrastructure can be built on these to reduce melting.
What will building pipelines and building on elevated piles do?
Cold air can circulate under stuctures and reduce effect of diffusion of heat from buildings.
How can drilling laterally beyond drilling platforms reduce effects on permafrost and vegetation.
Oil and Gas can be reached several Km from drilling sites so fewer drilling sites are required.
How can the use of technology reduce impacts on permafrost and vegetation?
powerful computers can detect oil and gas remotely so fewer exploritory well are needed.
What does refrigerated support do
Stabilises temp. of permafrost- used on Trans-Alaska pipeline.
Name a major carbon sink.
Permafrost estimated to contain 1600GT because cold temps slow decomposition of matter.
How much greater is the amount of carbon stored in soil than above ground biomass stores?
5X greater.
What season does the flux of carbon occur in and why?
In the summer when the active layer thaws and long daylight hrs mean plant grow rapidly.
The tundra used to be a carbon …. but there are concerns it may turn into a carbon …….
Sink and source.
Why might a negative feedback loop be reassuring?
More CO2 emisions means ice melts and plants can grow which absorb CO2
