Lec 6

Question 1

Permafrost is dependent on

Answer 1

Climate

Surface characteristics

Thermal properties of the ground

Question 2

Bogs active layer

Answer 2

Shallow active layers due to insulating properties of peat which dries in the summer

Question 3

Fens are wet which

Answer 3

Enhances the depth of the summer thaw

Question 4

Ice wedge formation

Answer 4

Frozen winter grown below -10 degrees begins to crack

Cracks fill with water in spring expanding the ice wedge

This pushes up soil

Question 5

Ice-wedge polygons go from what to what over time

Answer 5

High centered to low centered over time

Question 6

Thermokarst lakes (Thaw lakes)

Answer 6

Body of freshwater, usually shallow, that is formed in a depression by melt water from thawing permafrost

Depressions often produced by collapse of ground levels associated with permafrost thaw

Question 7

Ebullition

Answer 7

Bubbling of methane from decomposition

Question 8

Coastal erosion

Answer 8

Sea level rise

Longer open water periods

Question 9

Climate change implications of peatlands

Answer 9

Greater quantities of methane are emitted which offset atmospheric CO2

Enhanced warming at high latitudes could result in a positive feedback as increasing rates of anaerobic microbes yield a higher quantity of methane