Arctic Tundra

What is permafrost?

Ice underground that is permanently frozen

Wha is the active layer?

Sits on top on the permafrost

How much land does the arctic tundra cover

and where is it found?

What are the requirements to be an arctic tundra?

-Summer temps must peak at =<10^oC for a month in July

Properties of permafrost

-Stores an estimated 1600GT of carbon
-Melting would release lots of CO2
-Leads to poor drainage

Arctic Tundra Water Cycle

-Annual precipitation - >100mm a year and mostly falls as snow
-Low flows due to high residence times
-Sparse plants meaning low evapotranspiration
-Limited groundwater and soil moisture stores as permafrost is a barrier to infiltration/percolation
-Low humidity due to low water in atmosphere

Arctic Tundra Carbon Cycle

-Permafrost=Major Carbon Sink at 1600GT
-High carbon content from low temperatures slowing decomposition
-Carbon in soils 5* higher than above ground biomass

What impact does seasonal change have on both the water and carbon cycles?

-3 month summer and 9 month winter
-Latitude can mean 24hr sun in peak of summer and 24hrs of dark in peak of winter

Physical Factors affecting Flows and Stress of Water in Arctic Tundra - Temperature

-Avg temp well below freezing

Physical Factors affecting Flows and Stress of Water in Arctic Tundra - Rock Permeability and Porosity

-Permeability is low due to permafrost
-Geology dominated by precambrian igneous and metamorphic rock in Arctic Tundra of Alaska

Physical Factors affecting Flows and Stress of Water in Arctic Tundra - Relief

-Ancient rock surface reducing to gently sloping

Physical Factors affecting Flows and Stress of Carbon in Arctic Tundra - Temperature

-Unavailability of liquid water + low temperatures slowing decomposition

Physical Factors affecting Flows and Stress of Carbon in Arctic Tundra - Vegetation and organic matter in soil

-Poorly decomposed in permafrost
-Lost of biological carbon has been stored away for over 500

Physical Factors affecting Flows and Stress of Carbon in Arctic Tundra - Mineral composition of rocks

-Mineral composition + permafrost = Little influence on carbon/water cycle

What is our mini case study for the arctic tundra

-The Alaskan Oil and Gas Industry

Alaskan Oil and Gas industry Summary

-Located on Alaska's north slope
-Accounts for 4% of the USA's domestic oil production
-Formerly 25% in the 1990s

Oil and Gas industry impact on water cycle

-Melts permafrost and snow-cover leading to increased run off and discharge
-Strip mining for aggregates (sand/gravel) for construction creates artificial lakes that disrupts natural drainage patterns
-Near these

Oil and gas industry impact on carbon cycle

-Highly sensitive due to thermal balance changing
-CO2 emissions up by 73% from 1975
-Melting permafrost releases methane and CO2
-Estimated loss of 7-40 mil tonnes yearly

What is dust deposition?

Dust settles on snow darkening it

What are the five main management strategies to moderate the impact on carbon and water cycles?

-Insulated ice and gravel pads
-Elevated piles
-Drilling laterally
-Supercomputers to model oil and gas reservoirs
-Refrigerated supports

What are insulated ice and gravel pads?

-Sediment of roads can act as a physical barrier for permafrost
-This is non-frost susceptible and limits the process of freezing and thawing moving rocks to the surface (known as frost heave)
-This is often used in roads

What are elevated piles?

-Steel pilings

How does drilling laterally moderate impact in the Arctic Tundra

-Oil/gas drill vertically

What effects to supercomputers have

-By creating seismic waves in the ground

Effects of refrigerated supports

-Over half of trans-alaskan pipelines run above ground so hot oil doesn't melt any permafrost
-These pipelines can be elevated by up to 78