2b. Its is possible to identify the physical and human factors that affect the water and carbon cycles in the arctic tundra

Question 1

How many km of land does the tundra occupy?

Answer 1

Some 8 million km2 in Northern Canada , Alaska and Siberia.

Question 2

describe the climatic condition of the tundra

Answer 2

severe and become more extreme with latitude

Question 3

What happens for 8 or 9 months of the year in the tundra?

Answer 3

It has a negative heat balance, average monthly temperatures are below freezing.

Question 4

Describe precipitation in the tundra

Answer 4

mean annual precipitation is low.

Question 5

What feature of the arctic tundra provides some brevity for the growing season?

Answer 5

Long daylight hours

Question 6

How much precipitation falls annually in the tundra and what does most of it fall as?

Answer 6

50-350mm
Snow

Question 7

Why is there limited transpiration in the tundra?

Answer 7

The spareness of vegetation and short goring season.

Question 8

Why are rates of evaporation low in the tundra?

Answer 8

Much of the suns energy in summer is expended melting snow so that ground temperatures remain low to inhibit convection. Surface soil is also frozen for most of the year.

Question 9

Why does the tundra have limited groundwater and soil moisture stores?

Answer 9

Permafrost acts as a barrier to infiltration. percolation, recharge and ground water flow

Question 10

What sparks the sharp increase in river flow in the summer?

Answer 10

Melting of snow, river and lake ice and the uppermost accumulated in winter months active layer

Question 11

Why are there extensive wetlands in the tundra?

Answer 11

Permafrost impedes drainage, creating a temporary water store.

Question 12

Describe the tundra ecosystem

Answer 12

Treeless, very few species can survive low biodiversity, vegetation provides discontinuous ground cover in the southern areas.

Question 13

How much carbon is the tundra permafrost estimated to contain?

Answer 13

1600 GT

Question 14

Why does the tundra act as such an affective carbon sink

Answer 14

The low temperatures mean low rates of decomposition of dead animal and plants material.

Question 15

How many times greater is the below ground carbon storage in the tundra than the above ground biomass?

Answer 15

5

Question 16

When is the flux of carbon concentrated?

Answer 16

in the summer months when the active layer thaws.

Question 17

Why do plants grow rapidly in the short summer in the tundra?

Answer 17

Long hours of daylight allow for a short but intensive growing season.

Question 18

What is the NPP in the tundra?.

Answer 18

less than 200g/m2/year

Question 19

What is the biomass in the tundra

Answer 19

Relatively small, ranging between 4 and 29 tonnes/ha depending on vegetation cover.

Question 20

Describe the flux of carbon to the atmosphere in summer/growing season

Answer 20

During the growing season plants input carbon rich litter into the soil. the activity of micro organisms also increases , releasing co2 into the atmosphere through respiration.

Question 21

Why are Co2 and methane emissions from the tundra not confined to the summer?

Answer 21

pockets of unfrozen soil act as sources of ch4 and co2
Snow cover can also insulate microbial organisms to aid decomposition.

Question 22

Why is the tundra becoming a carbon source rather than sink?

Answer 22

Global warming.

Question 23

why is the evidence for the tundra as a source of co2 unclear?

Answer 23

While levels of CO2 emission have increased, the warmer temperatures have also increased vegetation cover, increased the intake of co2 by photosynthesis. This has intern increased leaf litter entering soil. Therefore it is possible that the balance can be maintained.

Question 24

How does temperature affect Drainage in the tundra?

Answer 24

Average temperatures are very low so most water stays frozen in the permafrost. During the short summer the active layer thaws and liquid water flows on the surface. Meltwater forms thousands of small pools and shallow lakes. drainage is poor because water cannot infiltrate the soil due to permafrost.

Question 25

How does temperature affect evapotranspiration in the tundra?

Answer 25

it is prevented in the cold winter, in summer, some occurs from standing water, soil and vegetation.

Question 26

Describe permeability of rock in the tundra

Answer 26

low owing to permafrost and crystalline rocks which dominate these areas.

Question 27

What happened to the ancient rock surface in the tundra?

Answer 27

it has been reduced to a slightly undulating plain by millions of years of erosion and weathering. Minimal relief and chaotic glacial deposits mea that drainage is impeding, causing water logging in the summer months.

Question 28

How is most carbon stored in the tundra and for how long?

Answer 28

Mainly stored as decomposed plants remains In permafrost. Most of this carbon has been locked away for 500,000 years at least.

Question 29

why is plant growth, biomass and NPP limited? tundra

Answer 29

Low temperatures, unavailability of liquid water and parent rocks containing limited minerals for plant growth.

Question 30

What is permafrost melting in the tundra associated with?

Answer 30

• construction and operation of oil and gas pipelines diffusing hear discreetly into the environment
• dust deposition along roadsides decreasing the albedo affect
  -removal of vegetation cover, exposing permafrost

Question 31

How much co2 is estimated to be lost from the north slope in Alaska per year from permafrost melting?

Answer 31

from 7 to 40 million tonnes.

Question 32

How does destruction of tundra vegetation lead to increased carbon released?

Answer 32

Less photosynthesis, increased soil thawing = increased microbial activity, decomposition. All lead to more co2 into the atmosphere.

Question 33

Why might recovery of tundra vegetation take decades?

Answer 33

Tundra veg is very slow growing

Question 34

How does melting permafrost increase river discharge?

Answer 34

Melting permafrost and snow cover increase surface run-off, making flooding more likely.

Question 35

How does the increased run off and flooding affect as a result of anthropogenic activity affect evaporation in the tundra?

Answer 35

More extensive wetlands mean more evaporation.

Question 36

How does strip mining of aggregates affect the water cycle in the tundra?

Answer 36

It creates man made lakes which disrupt drainage and exposes permafrost to further melting.

Question 37

How do explosions used used for prospect oil and gas affect the water cycle in the tundra?

Answer 37

it disrupts drainage.

Question 38

What practice in Alaska reduces localised run-off?

Answer 38

The abstraction of water from creeks and rivers for industrial use

Question 39

What us the more pragmatic angle for protecting permafrost?

Answer 39

To prevent destruction of houses and infrastictye but melting.

Question 40

What us the more pragmatic angle for protecting permafrost?

Answer 40

To prevent destruction of houses and infrastructure by melting.

Question 41

How will insulated gravel ads help to reduce permafrost melting?

Answer 41

If roads are constructed on isolating ice or gravel pads the permafrost will be protected.

Question 42

how will elevating building and pipelines help to ease permafrost melting?

Answer 42

It allows cold air to circulate beneath these structures.

Question 43

How will drilling laterally beyond drilling platforms help to reduce permafrost losses?

Answer 43

New drilling techniques allow oil to be extracted further away from the drilling site this would greatly reduce the impacts on pf and vegetation.

Question 44

How will more powerful computers help to reduce permafrost losses?

Answer 44

Fewer exploration wells will be needed.

Question 45

How will refridgerated supports help to reduce permafrost losses?

Answer 45

used on the trans alaskan pipeline to stabilise permafrost temperature.