Water and Carbon Cycles- Carbon Stores

Question 1

Marine sediments and sedimentary rocks as a carbon store

Answer 1

• largest store or carbon
• long term store
• rocks take millions of years to form

Question 2

Oceans as a carbon store

Answer 2

• CO2 is absorbed directly from the air and river water discharges carbon carried in solution
• since industrial rev. oceans have absorbed more CO2 from the air due to increasing carbon emissions

Question 3

Fossil fuel deposits as a carbon store

Answer 3

• hydrocarbons are important long term stores
• exploited since industrial rev. for heat and power
• this combustion has pumped huge amounts of CO2 into the atmosphere

Question 4

Soil organic matter as a carbon store

Answer 4

• soils contains rotting organic matter
• carbon can remain in soils for hundreds of years
• deforestation, land use change and soil erosion can release the stored carbon rapidly

Question 5

The atmosphere as a carbon store

Answer 5

• carbon is held in the atmosphere in the form of CO2
• amount has increased due to power stations, vehicles and deforestation
• caused enhanced greenhouse effect

Question 6

Terrestrial plants as a carbon store

Answer 6

• plants are vital for all life on Earth
• convert Sun’s energy to carbohydrates
• can store carbon for years and transfer it into the soil
• deforestation releases it back into the atmosphere

Question 7

Lithosphere definition

Answer 7

Rigid outer part of the Earths crust

Question 8

Hydrosphere definition

Answer 8

All the water on the Earth’s surface

Question 9

Biosphere definition

Answer 9

The total sum of all living matter

Question 10

Atmosphere definition

Answer 10

All the gases that are around the planet

Question 11

Cryosphere definition

Answer 11

Frozen water part of the Earth’s system

Question 12

Pedosphere definition

Answer 12

The outermost later it the Earth that is composed of soul and subject to soil formation process

Question 13

How is carbon stored in the lithosphere?

Answer 13

-stored in both organic and inorganic forms
Organic: litter, organic matter and humic substances found in the soil
Inorganic: fossil fuels and oil shale
The carbon is distributed like this:
-marine sediment and sedimentary rocks- 100 million GtC
-soil organic matter- 1500 GtC
-fossil fuels- 4100 GtC
-peat- 250GtC

Question 14

How is carbon stored in the biosphere?

Answer 14

Living vegetation
-19% of biosphere carbon stored in plants
-much of this stored directly in plant tissue
-Amazon basin contains 20% of world’s forest carbon
Soil humus
-originates from litter decomposition
-in forests 31% of carbon stored in biomass, 69% in the soil
Animals
-have a small role in carbon storage
-very important in generation of movement of carbon through the carbon cycle

Question 15

How is carbon stored in the atmosphere?

Answer 15

• estimated amount of carbon 720-800 GtC
• carbon makes up 0.04% of the atmosphere
• levels of carbon are highest for 8000 years
• CO2 trapped in ice cores from Antarctica and Greenland can be used to give ‘proxy’ measure of the CO2 in the atmosphere

Question 16

How is carbon stored in the hydrosphere?

Answer 16

Ocean stores divided into 3 categories:

• surface layer (euphoric zone): where sunlight penetrates so that photosynthesis can take place (900 GtC)
• intermediate layer (twilight zone): deep layer of water containing 37,100 GtC
• living organic matter (fish, plankton, bacteria etc.): amount to 30 GtC and dissolved organic matter 700 GtC
• decaying organisms release CO2 into deep water
• some material sinks to the bottom and forms carbon rich sediments

TOTAL GtC FOR SEDIMENTARY LAYER: 100 MILLION