The Arctic Tundra Flashcards
How big is the Arctic tundra?
8 million km2
What countries/regions is the Arctic tundra in?
Canada, Alaska, Siberia
Where does the Arctic tundra extend to/from?
from the northern edge of the boreal coniferous forest to the Arctic Ocean
What is the southern limit of the Arctic tundra?
the 10 degrees July isotherm
For how many months does the tundra have a negative heat balance (average temperatures below freezing)?
8 or 9 months
For how long is the ground frozen?
permanently
How much permafrost thaws in the summer?
top metre
What happens in winter?
the sun remains permanently below the horizon and temperatures reach -40
Why is there low biodiversity?
few plants and animals have adapted to the extreme environment
What plant is not present?
trees
What is the annual preciptiation?
low - 50-350mm
what form is most of the precipitation?
snow
why is there low humidity
the cold
why is there little transpiration
sparse vegetation and short growing season
why is there low evaporation
the Sun’s energy is used to melt snow and most surface water is frozen
what is permafrost a barrier to?
infiltration and percolation = limited groundwater stores
what accumulates in winter
snow and ice
why does river flow increase in summer
snow/ice and active layer melt
why are there wetlands in summer
permafrost limits drainage of melted ice
how much carbon does the tundra contain
1600 Gt
what slows decomposition
low temperatures
how much more carbon is there in the soil than the above ground biomass
5X
what do long daylight hours in summer allow for
rapid plant growth
what is the NPP
200 g/m2/year
what is the biomass
4-29 tonnes/ha
what do plants input to the soil during the growing season
carbon-rich litter
the activity of what increases in summer, and what does this release
microorganisms - CO2 via respiration
What are a source of CO2 and CH4 in winter
pockets of unfrozen soil