ELSS - Arctic Tundra CS Flashcards
How much of the Northern Hemisphere does the permafrost cover?
1/4
Why is there a huge accumulation of organic matter in soils in the Tundra?
When living organisms die, organic detritus does not decompose completely due to the cold temperatures
What causes decomposition of organic matter?
Microorganisms and soil invertebrates
How much carbon has been released into the atmosphere since 1850?
350 billion tonnes
What gases does permafrost release?
CO2 and CH4
What is the significance of the 10 degree July Isotherm?
When it stays below 10 degrees in the summer months
What are the mean temperatures?
-15 degrees
Which part of the ground is not permanently frozen during summer?
The active layer
What temp can it get to in the winter?
-40 degrees
What is annual precipitation?
<100mm
Whats the most common form of precipitation?
Snow
What is the length of the growing season?
3 months
What happens in the summer in the Arctic Tundra?
- Vegetation store increases - increased evaporation, photosynthesis
- Permafrost thaws - release of greenhouse gases
- More moisture in the ground
- Ground heats up, convection
What is the min discharge in winter in of th Yukon river?
340 cumecs
What is the max discharge of the Yukon river in summer?
24,600 cumecs
Why does permafrost store carbon?
Due to cold temperatures, organic matter cannot decompose
- Low temp means anaerobic bacteria less effective
How much carbon stored in the ground?
5x more than above the ground
How is the carbon store in the summer?
- Higher rates of decomposition due to thawing of permafrost, so increases in the atmosphere
- Higher veg density so increased photosynthesis - growing season
How are carbon fluxes in the winter?
- Low veg density -> low photosynthesis, not enough sunlight
- Low decomposition rates
- Mainly stored in permafrost
How is respiration in the summer and winter?
Summer:
- Increased veg, lots of moisture from permafrost melt -> higher
Winter:
- Colder temps, little moisture -> lower
How much carbon does the permafrost store?
1,700 billion metric tons
How much heat does methane trap compared to carbon?
30x
What type of feedback is the thawing of the permafrost?
Positive feedback loop
What are human factors influencing the water an carbon cycle?
- Spine Road
- Ice roads
- Oil extraction - TAPS, pipelines
- Gravel pads
- Removal of vegetation for oil extraction
What are the effects of human factors to the Arctic Tundra?
- Reduction in surface albedo
- Direct thermal transfer
- Melting permafrost
- Deepening active layer
- Formation of talik
- Thermokarst lakes
What do gravel pads generate?
Dust
What are the physical factors affecting the water and carbon cycle in the Arctic Tundra?
- Temperature
- Relief
- Vegetation density
- Sunlight
- Porosity
- Soil
What are the two types of permafrost?
Continuous and discontinuous
