Carbon Negative And Positive Feedback

Question 1

Example of Negative Feedback, in relation to plant growth

Answer 1

1. CO2 in the atmosphere increases
2. Extra CO2 causes plants on land and in oceans to increase their growth
3. Plants remove and store more CO2 from the atmosphere
4. Amount of CO2 in the atmosphere is reduced so damps down initial change

Question 2

Example of Negative Feedback, in relation to ocean salinity

Answer 2

1. More CO2 in the atmosphere increases temperatures
2. Fresh water stored as ice is released into polar oceans
3. Salinity levels in the ocean fall - which disrupts ocean circulation
4. The Gulf Stream is slowed and temperatures fall – but not globally

Question 3

Example of Positive Feedback, in relation to plant respiration

Answer 3

1. CO2 increase = Temperature rises
2. Plant Respiration rises
3. Amount of CO2 in Atmosphere increases
4. Enhanced greenhouse effect, so amplifies initial change

Question 4

Example of Positive Feedback, in relation to ice melting

Answer 4

1. Atmospheric temperatures rise as a initially as a consequence of the EGE
2. Ice sheets and ice bergs melt
3. Reflective light surfaces are replaced by darker oceans which absorb heat
4. Ocean temperatures increase further

Question 5

Example of Positive Feedback, in relation to decomposition

Answer 5

1. Temperatures rise in cold Tundra regions and so permafrost melts
2. Decomposition of DOM by decomposers can now take place
3. Decomposers produce CO2 and methane as waste products
4. So carbon is released into the atmosphere – adds to the EGE

Question 6

Example of Dynamic Equilibrium

Answer 6

• Ocean acidification results from the diffusion of more CO2 into oceans.
• Carbonite ions used by marine organisms to make shells are reduced. This is because the carbonic acid which results from the dissolved CO2 then reacts with the carbonic ions to produce bicarbonate.
• However, more acidic oceans also leads to more rapid weathering of sedimentary rocks such as limestone and chalk which release carbon ions into the ocean
• So as more carbon ions are then released into the ocean from this weathering…….the balance is restored. Dynamic equilibrium!