Artic tundra Flashcards
How big is the artic tundra
8 million km^2
For how many months does the tundra have a negative heat balance
9 months
What is the weather like Artic tundra
can get to -40 degrees centigrade
Annual precipitation 0f 50-350 mm (low)
What is the water cycle like in the Artic
Limited transpiration due to limited trees
Low rates of evapotranspiration as most of the suns energy is expended melting and not boiling
Limited groundwater as permafrost is a natural barrier to percolation infiltration and groundwater flow
Extensive wetlands in summer due to melted ice
How much carbon is stored in the permafrost of the Artic
1600 GT (big)
How much of the carbon is stored in above ground instead of below ground sources
The amount of carbon in tundra soils is 5x greater than in the above-ground biomass
What is the NPP and biomass of the tundra
200 grams/m^2/year
4 and 29 tonnes per hectare biomass
Describe the physical factors and seasonal changes stores and flows of the water cycle in the tundra
Average temperatures are below freezing so water is stored as ground ice in permafrost layer
Permeability is low owing to the permafrost and crystalline rocks which dominate the geology
The ancient rock surface that underlies the tundra has been reduced to a great undulating plain by millions of years of erosion
Describe the physical factors and seasonal changes stores and flows of the carbon cycle in the tundra
Carbon is mostly stored as partly decomposed plant remains this has been locked away for >500000 years.
There is little to no growing season as the summer is only 3 months long
Low temperatures and waterlogging slow decomposition and respiration
Owing to the impermeably of the permafrost, rock permeability the rocks exert little influence on the water and carbon cycle
Where was an oil and gas production set up in an Alaskan tundra
Prudhoe bay in 1968
How much did the prudhoe plant produce
A quarter of USAs domestic oil production
What impact has the Prudhoe oil and gas extraction had on the local tundra
Construction and operation of oil and gas installations diffuse heat directly to the environment
Dust deposition on side of roads decreases the albedo effect so more snow melts
removal of vegetation cover that insulates the permafrost makes it more susceptible to melting
How much carbon does permafrost melting lose
Varies from 7 to 40 million tonnes/year while CH4 losses range from 24000 to 114000 tonnes /year
What strategies have been put int place to stop the impact of development on water and carbon cycles
Insulating ice and gravel paths - stops permafrost melting
Building pipelines and buildings on stilts - allows cold air to circulate underneath the pipes so the permafrost doesn’t melt
Drilling laterally - Oil and gas be removed from far away so that less sites need to be created
More powerful computers used to map out the oil and gas reserves so less exploration wells need to be built
Refrigerated supports - trans Alaska pipeline to keep the pipeline cool
How does forestry impact the carbon and water cycle
Higher rates of rainfall interception in plantations in natural forests in eastern England for sitka spruce = 60 percent - This leads to less run-off and more evaporation
Uk mature forest trees contain 70-200 tonnes of carbon/hectare ten times higher than grassland and 20 times higher than heathland Soil carbon is measured at 500 tonnes per hectare
Water extraction on river Kennet
area of 1200 km ^2
an chalk which is very permeable thus lots of groundwater water extraction has caused the rate of groundwater to exceed rates of recharge
Lower flows has led to reduced flooding
Lower groundwater has caused springs and seperages to dry up
What is a n artesian basin
An aquifier confined between impermeable rocks. When a well is is created water will rise as it is under artesian pressure to the height of the water table
What is the water table
The height of the water underground
How has London been struggling with the water table
Due to industrial revolution up until 1950 the water table fell by 90 metres since 1990s it has been rising by 3m/year flooding some parts of London’s cellars London then got permission to regulate it
Fossil fuels impact on CO2
Fuel releases 10 billion tonnes of CO 2 annually Today Co2 is the highest it has been in 800,000 years
What is positive feedback and what is negative feedback
Positive = multiplier effect
Global warming speeds up
decomposition speeds up CO2
More water vapour = higher temperatures(reflects long wave radiation) = higher temperatures
negative = keeping things the same as they were neutralising Ocean PH by increasing photosynthesis
More water vapour = more cloud cover = less radiation = less evaporation
How has wetland restoration been used to stop the carbon cycle
Contain 35 percent of carbon in th e lower 48 us states wetlands have halved. Canada originally lost 70per cent of their wetlands but now plan to restore some balance with creating 112000 ha oof wetlands to store 364000 tonnes per year of carbon one hectare can store 3.25 tonnes of carbon
How has afforestation been used to stop the carbon cycle
China aims to reforest 400000km^2 by 2050 In the 2000-2009 decade 30000 km^2 was planted
How has changing farming practices been used to stop the carbon cycle
Contour ploughing to reduce run-off
Zero tillage - dont plough soil so no CO2 is released
-improve quality of animal feed to slow CH4 emissions
Control the way manure decomposes to reduce CH4 emissions and use it as a renewable source of energy
