Arctic Tundra Water and Carbon case study

Question 1

how big and where is the Arctic tundra?

Answer 1

8 million square km
in Canada, Alaska, Siberia
southern limit extends to 10 degree July isotherm

Question 2

what is the climate like in the Arctic isotherm?

Answer 2

climatic conditions become more severe with latitude
for 8/9 months a year, the tundra has a negative heat balance

Question 3

how does the climate effect the ground in the arctic tundra?

Answer 3

permanently frozen, with only the top metre thawing in the summer

Question 4

what is the ecosystem like in the arctic tundra?

Answer 4

low biodiversity
few plants and animals are adapted to the severe climate
treeless, apart from a few dwarf species

Question 5

what are the 6 main features of the Arctic tundra?

Answer 5

-low annual precipitation as most lands as snow
-small moisture stores in atmosphere due to low temperatures reduce humidity
-limited transpiration because of sparse vegetation
-low rates of evaporation as much of the suns energy is expended on melting snow
-limited groundwater and soil moisture stores, permafrost is a barrier for infiltrator, percolation, and groundwater flow
-accumulation of snow and river/lake ice during winter
-extensive wetlands ponds, lakes during summer

Question 6

how much carbon does permafrost hold?

Answer 6

1600 GT
carbon sink

Question 7

how has permafrost managed to hold so much carbon?

Answer 7

due to low temperatures which allows slow decomposition of dead material

Question 8

when is a flux of carbon released from the permafrost?

Answer 8

summer months

Question 9

what is the tundras biomass?

Answer 9

between 2 and 29 tonnes/hectare each year
low biomass

Question 10

what do plants input into the soil and when?

Answer 10

during growing season
input carbon rich litter

Question 11

what are the physical factors, seasonal changes and stores of water?

Answer 11

-average temperatures are well below freezing for most of the year, meaning that water is stored as ground ice in the permafrost
-during short summer, the shallow active layer thaws and water flows on the surface, drainage is poor
-humidity is low all year
-permeability is low due to the crystallised rocks which dominate geology

Question 12

what are the physical factors, seasonal changes and stores of carbon?

Answer 12

-carbon is mainly stored as party decomposed plants which remain frozen in the permafrost
-most of the carbon has been locked away for 50,000 years
-low temperatures, water unavailability and poor rock minerals has lead to the total biomass of the tundra being low
-growing season for plants is only 3 months
-low temperature and water logging leads to a slow rate of decomposition

Question 13

where was oil reserves found in Alaska and why was this a problem?

Answer 13

Prudhoe Bay
problems such as
-extreme cold
-long periods of darkness
-permafrost
-remote location with no accessibility

Question 14

what did the government build in Alaska to obtain the oil?

Answer 14

pipelines
roads
oil production plants
gas processing facilities
power lines
power generators
gravel quarries

Question 15

what did the government build in Alaska to obtain the oil? x7

Answer 15

pipelines
roads
oil production plants
gas processing facilities
power lines
power generators
gravel quarries

Question 16

impact of oil and gas extraction on the water and carbon cycles
how does melting occur

Answer 16

permafrost is extremely sensitive to temperature, and melting has been caused by construction and operation of oil and gas instillations
dust deposition on roadsides, creating darkened surfaces and increasing sunlight absorption
removal of vegetation cover which insulates permafrost

Question 17

how much carbon is released from the permafrost on the North slope per year?

Answer 17

40 million tonnes

Question 18

how else does human interaction cause carbon being released into the atmosphere?

Answer 18

oil spills and gas flaring
destruction of tundra vegetation, causes less photosynthesis

Question 19

in what ways does melting permafrost disrupt the water cycle?

Answer 19

increases surface run off and river discharge

Question 20

in what ways does human interaction affect the water cycle?
Drainage

Answer 20

strip mining fro aggregates such as sand and gravel, creates artificial lakes and disrupts water drainage
road construction and seismic explosions also disrupt drainage channels

Question 21

how do insulated ice and gravel pads help moderate the human impact on water and carbon cycles?

Answer 21

roads and other infrastructural features can be constructed on insulating ice or gravel pads, thus protecting the permafrost from melting

Question 22

how do building and pipelines elevated on poles help moderate the human impact on water and carbon cycles?

Answer 22

allows cold air to circulate beneath these structures
provides insulation against heat-generating buildings, pipework…

Question 23

how does drilling laterally beyond drilling platforms help moderate the human impact on water and carbon cycles?

Answer 23

new drilling techniques allow oil and gas to be accessed several kilometres from the drilling site meaning fewer sites are needed for drilling rigs, limiting the impact on vegetation and the permafrost due to construction is reduced

Question 24

how does computers to detect oil and gas help moderate the human impact on water and carbon cycles?

Answer 24

fewer exploration wells are needed thus reducing the impact on the environment

Question 25

how do refrigerated supports help moderate the human impact on water and carbon cycles?

Answer 25

used on trans-alaskan pipeline to stabilise the temperature of the permafrost
similar supports are widely used to conserve the permafrost beneath buildings and other infrastructure