total annual precipitation is 110 mm (summer 74mm and winter 36mm)

permafrost is defined as ground that remains below 0 degrees for at least 2 consecutive years

24% of the northern hemishpere land is under lain by permafrost - accounting for 1/5 of the worlds total land area (22.8 million km2)

permafrost is made of bedrock, sediment of mineral and organic origin and ice

15 billion tonnes of carbon stored annually in the permafrost (3 times the amount in all of the rainforest and twice the amount in the atmosphere)

the effects on people due to the permafrost is that there are dramatic changes to the coastline, homes are now built on stilts and water and electrical lines have to be over ground

definition - In environments containing permafrost, the active layer is the top layer of soil that thaws during the summer and freezes again during the autumn

plant mortality ^ which removes the strorage capacity of vegetation from the carbon cycle

there has been an average of 504 spills annually on the North Slope

4,532 spills between 1996 and 2004 = more than 1.9 million gallons of toxic substances

from the oil spills, it can reduce the insulating quality of vegetation and distribution of the surface (thermokarst) by thawing underlying ice-rich permafrost = ^ mobilisation of carbon

No oil company has ever successfully cleaned up a major spill. In 1989, the Exxon Valdez spilled 11 million gallons of oil into Alaska’s Prince William Sound. Exxon spent $2 billion trying to clean up and recovered less than 7 percent of the oil spilled.

physical disturbance to Arctic ecosystems = ^ soil warming and permafrost thawing = ^ soil organic matter and nutrient turnover. Typically, the productivity of the vegetation ^ however soil respiration also ^

A spill in winter on frozen tundra is easier to clean up than a spill in warmer periods because the material can be removed as frozen condition from the surface.

the U.S. Department of the Interior found that there’s a 75 percent chance of a major oil spill if an oil company finds oil and produces it.

the net Carbon balance in the artic tundra may be -ve or +ve depending on the time scale

GPP = gross primary productivity = the overall rate of biomass production in an ecosystem

RA = respiration by plants/autotrophs (can produce their own food)

RH = respiration by animals/heterotrops (cannot produce own food)

RE = ecosystem respiration and GEP = gross ecosystem production are measured in moles per unit area and time

NEP (-ve in winter/night normally due to the lack of light/warmth which makes photosynthesis slower and respiration dominates leading to biomass lost and +ve in day/summer, more photosynthesis rather than respiration leading to more biomass accumulated)

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

that permafrost stores more carbon than has ever been released by humans via fossil fuel combustion

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

the low stature (height) of the vegetation prevents the development of a multi-layered canopy

wind and soil disturbance limit the amount of carbon produced in the biosphere

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

Most of the respiratory CO2 and CH4 losses from Arctic systems move directly to the atmosphere.

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

when some of the permafrost is melted it forms thermokarst, a terrain-type, characterised by very irregular surfaces of marshy hollows and small hummocks formed as ice-rich permafrost thaws

due to the extremely low NPPin the AT the loss of carbon the vegetative stores tend to be small however it can take 25-50 years for vegetation to recover

in Barrow, Alaska, found that only 290 g m2 of Carbon is stored in vascular plants compared to 18,992 g m2 stored in the permafrost

Oil can also increase the mortality of soil microorganisms responsible for the decomposition of organic carbon. This can slow the rate of carbon cycling and increase the amount of carbon stored within peat layers

Research has shown that 80 % of landscape-scale net CO2 emissions during September at a polygonal tundra landscape in Siberia were a result of degassing, 50% of this from CO2 outgassing from ponds

oil companies annually, emit 7 million to 40 million metric tons of carbon dioxide and 24,000 to 114,000 metric tons of methane. tthie effects the local carbon cycle by returning fossilised carbon back into the atmosphere increasing the concentration of carbon in the atmosphere.

Photosynthesis cannot happen during the winter months as it is covered by snow and can’t get sunlight

plant biomass is mostly below the grove as it is retreating from the harsh environment

Slow growing leaves, smaller leaves in the AT = plant adapts to reduce stress on the plant (don’t have to work as hard) and allows less biomass above the ground

Less photosynthesis as more biomass is stored below the ground – less carbon being taken in from the atmosphere – reduction in the carbon in the biosphere

Vegetation is highly dense – to trap heat from the ground, reduce rates of evaporation and protection from wind

Mono canopy – no layers – little competition – same/similar morphology (similar size and shape)

Character of biomass below the ground (roots) is large to what’s relative above the ground

Climate – two zones where dead organic matter sits at active layer and permafrost

From environment being so cold – more carbon is being stored in the atmosphere and less carbon in the soil

Reduction in high biodiversity meaning plants are more vulnerable to pests and disease

Low carbon in LIVING vegetation compared to TRF and temperate areas