Artic Tundra

Question 1

Background info

Answer 1

• 8 million square kilometres of Arctic tundra in Alaska, northern Canada and Siberia
• Low average temperatures of between 0 degrees and -30 degrees for 8-9 months of the year. During the remaining months, average temperatures are above 0°C and in some places can reach 10°C.
• The ground is permanently frozen but it thaws to a depth of about a metre during the summer months. This is the active layer.

Question 2

Water cycle in Alaskan tundra

Answer 2

• Precipitation, Low annual average, 50-350 mm; mainly snow
• Evapotranspiration Low temperatures = low rates of evapotranspiration; sun’s energy spent melting snow; most water remains frozen
• Run-off, Usually little flow but melting of active layer in summer can cause rapid increase in run-off and river flow
• Soil/ground Limited stores underground as permafrost a barrier to infiltration and percolation; summer melt causes temporary stores above ground as water cannot drain due to permafrost
• Atmosphere Small stores of water due to low temperatures
• Vegetation Low flows due to limited vegetation and short growing season

Question 3

Carbon cycle in Alaskan tundra

Answer 3

• Vegetation, Low NPP (200 g/msqaured/yr); low biomass
• Photosynthesis, Sequestration of CO, low; during summer there is rapid growth but still limited biomass for photosynthesis
• Atmosphere, CO2, released into atmosphere all year round but most during growing season via respiration
• Soil/ground, Permafrost stores vast amount of carbon; although accumulation is slow, there is five times more carbon here than above ground; concerns that permafrost becoming a carbon source rather than a carbon sink due to enhanced global warming

Question 4

Physical factors affecting the water cycle

Answer 4

• geology
• temperature
• relief