Arctic Tundra Flashcards
(27 cards)
What area does Tundra occupy?
8 million km^2 in Canada, Alaska and Siberia
What is the heat balance in the Tundra?
Negative heat balance 8-9 months a year
What is the mean annual precipitation?
50-350mm mostly as snow
What is biodiversity like?
Low biodiversity
Why is there limited transpiration?
Sparse vegetation and short growing season.
What does the heat balance mean for water?
Surface and soil water are frozen for most of the year
Why are there low rates of evapouration?
Most energy is used to melt the snow.
What is permafrost a barrier to?
infiltration, percolation, recharge and groundwater flow.
What happens in spring?
The spring melt opens up the active layer and causes a spike in river flow. Extensive wetlands and lakes on the tundra into summer. This is only a temporary store of water as permafrost impedes the drainage.
The flux of carbon is concentrated
How large is the permafrost carbon sink?
1600GT
What are the levels of decomposition?
very slow for plant material.
How much more carbon is in the soils than above ground biomass?
5 times more. Biomass is small, between 4-29 tonnes/ha
What is NPP?
Net Primary Productivity is less than 200grams/m^2/year
What is climate change doing to tundra?
Melting permafrost, moving the tundra from a carbon sink to a carbon source. Increased temperatures do mean increased growth which may have a balancing effect.
When and where were oil and gas discovered?
Prudhoe Bay 1968
What makes extraction difficult?
Harsh climate with extreme cold and long periods of darkness.
Flooding in summer.
Very remote and poor accessibility.
What have investments gone towards?
Pipelines, road networks, oil production plants, gas processing facilities, powerlines, power generators and gravel quarries.
Most were completed in 70’s and 80’s
How has North Slope oil production changed?
Early 90’s it accounted for 25% of USA oil
Now its only 6%
What is permafrost sensitive to?
Changes in the thermal balance.
What issues does oil and gas production bring?
Localised melting of permafrost arounf facilities.
Construction and operation diffuses heat directly into the atmosphere.
Dust deposition around roads, reduces albedo.
Reduction of vegetation cover which insulates permafrost.
How much are North Slope CO2 losses?
From 7-40 million tonnes/year.
How much are North Slope Methane losses?
24-114,000 tonnes/year.
What are other causes of changes to CO2 emissions?
Gas flarings and oil spillages.
Destruction of vegetation.
Why is destruction of vegetation so bad?
It takes a long time to recover due to slow growth rates.
