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ARTIC TUNDRA CASE STUDY - Coggle Diagram
ARTIC TUNDRA CASE STUDY
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the water cycle
background
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summer precipitation is a substantial portion of annual total, small contribution to annual runoff, large part of annual evapotranspiration due to strong seasonal energy variation
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ice wedges
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water goes into the cracks and circles and the vegetation rises and falls - plants growing around the water to protect it but can't grow in it or it will become damaged
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the carbon cycle
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the dominant carbon input to the Arctic ecosystem is by photosynthesis of vascular and non-vascular plants = GEP
carbon inputs at the leaf level are clearly limited in the ST by generally low irradiance and temperatures during short and late growing seasons despite having photosynthetic adaptions
canopy leaf area is low due to low soil nutrient availability (nitrogen especially) + limits the ability of the vege. to use newly-fixed carbon in growth bc growth requires adequate nutrients
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The dominant form of Carbon loss is as CO2, produced by both plants and soil biota. Autotrophic or plant respiration (RA) typically accounts for about half of GEP on an annual basis
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in the active layer, many of the biogeochemical processes (freezing and thawing) take place here and releases carbon in the gas, liquid or particulate form occurs via this layer
The major Arctic rivers drain C-rich peatlands and soils transport large quantities of organic Carbon to the Arctic Ocean
permafrost makes the geology of the place impermeable (no water in the ground – means the carbon is trapped and cannot be passed through water) the only part of the permafrost that is permeable is the active layer
Geology exerts little control over Carbon cycling in this arctic tundra region despite significant geological variation. This is because permeability and porosity of rocks are largely controlled
Geology exerts little control over Carbon cycling in this arctic tundra region despite the significant geological variation. This is because the permeability and porosity of rocks are largely controlled by permafrost.
Low rates of mineralisation and weathering the parent material has little influence on the mineralogical composition of soil and therefore does not impact on carbon dynamics.
Soil organic carbon is not as mobile in geologies where the parent material has pH characteristics that are basic on the pH scale. In such rock soil development is likely to be more basic on the pH scale and the mobilisation of soil organic carbon is not significantly affected by the underlying geology in sedimentary rocks
Carbon stored in peat in AT – 18,992 g C m-2 yr-1 compared to vegetation above and below ground is only 296 g C m-2 yr-1
not much carbon being transferred, just stored
things to learn
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RE = ecosystem respiration and GEP = gross ecosystem production are measured in moles per unit area and time
in the LT NEP must be +ve for the large accumulations of carbon in the Tundra ecosystem and in the ST, daily or seasonal basis the NEP can swing from strongly -ve/+ve
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geology and relief
barrow
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From the geology being frozen, the rock is impermeable, the carbon cannot be released or moved from the permafrost as water (the only way weathering can happen is with water) and as the permafrost has made the rock impermeable carbon cannot be released, not affecting the carbon cycle.
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relief
Slope/relief is steeper the more water would be running into an area leading to more dissolving of carbon (during the summer months)
more vegetation in lower relief during summer - more water is being flowed from the active layer (in the ST) and the permafrost (LT)
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