Assessment 2 - Spring 1

Question 1

Outline the process of decomposition in the carbon cycle. (4 marks)

Answer 1

• Decomposition is the breakdown of organic matter by bacteria
• Animals and bacteria are decomposers
• During decomposition Co2 is released
• Most of the carbon released is a result of decomposition

Question 2

Explain the role of cryospheric change in the water cycle. (4 marks)

Answer 2

• Cryosphere change in sea levels
  
  • The cryosphere is a major store of water
  • In cooling (e.g. glacial period) the cryosphere will grow in size. This is because the water cycle is slowed as the ice restricts the return of water to the sea and ocean
  • In a period of warming the cryosphere adds water to rise through increased volumes of water and thermal expansion
    E.g. permafrost

Question 3

Outline the processes operating in the slow carbon cycle. (4 marks)

Answer 3

• The slow carbon cycle transfers carbon between spheres over millions of years
  
  • Marine organisms build their shells by combining calcium with carbon when they die they accumulate on the ocean floor, over millions of years these organisms become compressed and become carbon-rich sedimentary rock
  • Oceanic crust, containing sedimentary rock, is subducted causing the crust to melt, the CO2 that was stored in the rock is released into the atmosphere through volcanic eruptions
• Sedimentary rock near the surface release CO2 as they are chemically weathered. Water flowing over sedimentary rock dissolves it transporting carbon to the oceans

Question 4

Using figure 2 and your own knowledge, assess the challenges associated with reducing greenhouse gas emissions (6 marks)

Answer 4

AO1:
* Human impact - farming practices, deforestation
* Human intervention

AO2:
* Rich countries (e.g. Europe and USA) contribute to global warming