8km^2 across Alaska, Canada and Siberia ranging from North edge of boreal conferious forest to Arctic Ocean.
Few animals and plants can survive due to permafrost predominantly covering it because it is always below freezing temperature.
Permafrost is a major source of CO2 and CH4.
Plant diversity and distribution is discontinous and in winter temperatures can be as low as -40 degrees celcius.
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Arctic Tundra Carbon Cycle.
Being able to contain 1600 GT of carbon globally, permafrost is a vast carbon sink.
The tundra contains five times as much carbon as the below-surface biomass.
Mircoorganisms and animals produce more carbon dioxide as they aerobically respire more during growing season, therefore adding more atmospheric carbon.
Tundra is thought of becoming a carbon source with global warming being a concern with carbon outputs increasing with ongoing decades.
However, the carbon budget might remain stalbe despite climate change due to increasing temperatures providing higher plant growth. This means vegetation can act as a carbon sink as they photosynthesise.
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Arctic Tundra Water Cycle.
Generally low precipitation rate (50-350mm) - mostly snow.
Low atmospheric moisture from low temperatures.
Low rates of evapotranspiration due to sparce vegetation diversity - most of sun's solar energy goes into melting snow.
Limited infiltration capacity due to permafrost being a physical barrier to percolation and infiltration, therefore low groundwater flows and moisture storage.
Accumulation of snow and lake ice results in sharp riverflow increase.
Extensive wetlands/lakes during summer due to more melted snow.
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Physical Factors.
Average temperatures for majority of the year are well below freezing point therefore water is in ice storage in permafrost layer.
The top metre thaws in the summer, becoming liquid and causing increased surface flow.
This forms wetlands, pools and shallow lakes in the landscape.
Dominant crystalline rocks and deep permafrost lower permeability of ground.
Carbon is mainly stored as partially decomposed vegetation in permafrost for half a million years at least.
Photosynthesis and NPP are low due to lack of vegetation and biodiversity; from low temperature, limiting enzyme activity and liquid water flow.
Low temperatures and waterlogging result in low decomposition and aerobic respiration, lowering the release of carbon dioxide into the atmosphere.
The total carbon storage of biomass is small for these reasons.
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Impacts on Water Cycle.
Construction and operation of oil/gas productions/installations/infastructure directly diffuses heat into environment.
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