arctic tundra carbon and water cycles

Question 1

what is meant by the term tundra

Answer 1

an ecosystem/ biome found at the north and south poles or at the top of a mountain

Question 2

where is the arctic circle

Answer 2

66 degrees north of the equator

Question 3

how much land does the arctic tundra occupy and in what regions

Answer 3

8 million km2 in northern canada, alaska and siberia

Question 4

what is a negative heat balance

Answer 4

more outputs of heat than inputs. inputs are from solar radiation, outputs are from the release of gas and land

Question 5

for how many months of the year does the arctic tundra have a negative heat balance and how will temperatures be during this time.

Answer 5

8-9 months. average monthly temperatures will be below freezing

Question 6

what impact does the negative heat balance have on the ground

Answer 6

the ground is permanently frozen, only the top metre or so thaws during the arctic summer.

Question 7

what underlies much of the tundra

Answer 7

permafrost, which is an important feature of the regions water cycle.

Question 8

how low can temperatures drop during the winter

Answer 8

in winter for several weeks the sun remains below the horizon, temperatures can plunge below -40 degrees.

Question 9

what feature of the summer months assists plants growing

Answer 9

long hours of daylight in the summer provide some compensation for the brevity of the growing season

Question 10

what is precipitation like

Answer 10

mean annual precipitation is low (50-350mm)

Question 11

what is biodiversity like

Answer 11

few plants and animals have adapted to this extreme environment, biodiversity is low and apart from a few dwarf species, the landscape is treeless.

Question 12

how does variation vary based on latitude

Answer 12

conditions get harsher with latitude, in southern areas (the low arctic) conditions are less severe and vegetation provides a continuous ground cover. Further north in the high arctic, plant cover is discontinuous and there are extensive areas of bare ground.

Question 13

what are stores of moisture in the atmosphere like at he tundra

Answer 13

small stores of moisture in the atmosphere owing to low temperatures

Question 14

how does small amounts of vegetation impact the water cycle

Answer 14

limited transpiration because of sparseness of vegetation cover and the short growing season

Question 15

what is evaporation like

Answer 15

low rates of evaporation. much of the suns energy is expended melting snow and ice so ground temperatures remain low and inhibit convection.

Question 16

how does permafrost impact groundwater and soil water

Answer 16

limited groundwater and soil water because permafrost acts as a barrier to infiltration, percolation, recharge and groundwater flow

Question 17

how is riverflow impacted during the summer months

Answer 17

melting snow, river and lake ice, and the uppermost active layer of the permafrost in spring and early summer results in a sharp increase in river flow

Question 18

what occurs as a result of permafrost impeding drainage

Answer 18

extensive wetlands, ponds and lakes in the summer months. this temporary store of liquid is as a result of permafrost which impedes drainage.

Question 19

why is permafrost significant to the carbon cycle

Answer 19

it has been a vast carbon sink, but now with climate change there are concerns of it becoming a carbon source

Question 20

how much carbon is permafrost estimated to store globally

Answer 20

1600GT

Question 21

why is there such an accumulation of carbon in tundra soils

Answer 21

accumulation of carbon is due to low temperatures which slow decomposition of dead plant material

Question 22

what is the NPP is the arctic tundra

Answer 22

less than 200 grams/m2/year

Question 23

describe the tundra biomass using figures

Answer 23

the tundra biomass is small- between 4-29 tonnes/ha depending on the density of the vegetation cover

Question 24

how is the growing season in the tundra significant to its carbon cycle

Answer 24

during the growing season plants input carbon-rich litter to the soil and the activity of micro-organisms increases, releasing CO2 into the atmosphere by respiration

Question 25

describe the tundra’s carbon cycle in winter

Answer 25

pockets of unfrozen soil and water act as sources of C02, meanwhile snow cover may insulate microbial organisms allowing some decomposition despite the low temperatures

Question 26

how do increasing temperatures allow a decrease in the release of C02 into the atmosphere as well as an increase

Answer 26

melting permafrost results in greater amounts of carbon being released, however higher temperatures have stimulated plant growth and a greater uptake of C02 for photosynthesis, but also increasing the amount of plant litter entering the store

Question 27

what are the the three main factors that influence flows and stores of water in the tundra

Answer 27

temperature, relief and rock permiability

Question 28

what is the dominant rock type in the tundra and how does this influence permeability

Answer 28

crystalline rocks dominate the geology of the tundra in arctic and sub-arctic Canada, meaning adding to the lack of permeability as a result of permafrost

Question 29

describe relief in the tundra

Answer 29

the ancient rock surface which underlies the tundra has been reduced to a gently undulating plain by hundreds of millions of years of erosion and weathering.

Question 30

how does relief affect the water cycle in the tundra

Answer 30

minimal relief and chaotic glacial deposits impede drainage and contribute to waterlogging during the summer months

Question 31

what is the main way that carbon is stored in the tundra

Answer 31

carbon is mainly stored as partly decomposed plant material frozen in the permafrost. most of the carbon has been locked away for at least the past 500,000 years.