Biogeochemical cycles

Question 1

What are the carbon reservoirs

Answer 1

• atmosphere
• hydrosphere
• lithosphere (rocks and fossil fuel)
• living things
• dead organic matter

Question 2

What is photosynthesis and how does carbon move from one reservoir to another

Answer 2

• plants use sunlight to synthesise nutrients from carbon dioxide and water
• atmosphere - biosphere

Question 3

What is respiration and how does carbon move from one reservoir to another

Answer 3

• living organisms involving the production of energy intake of oxygen and release of CO2
• biosphere - atmosphere

Question 4

What is food chain transfer and how does carbon move from one reservoir to another

Answer 4

• transfer of matter and energy in the form of food from organism to organism
• biosphere - biosphere

Question 5

What is fossilisation and how does carbon move from one reservoir to another

Answer 5

• animal or plant becoming preserved in a hard form
• biosphere - lithosphere

Question 6

What is combustion and how does carbon move from one reservoir to another

Answer 6

• chemical combination of a substance with oxygen, involving the production of heat and light
• lithosphere - atmosphere

Question 7

What is decomposition and how does carbon move from one reservoir to another

Answer 7

• break up into constituent parts by or as if by a chemical process
• biosphere - atmosphere

Question 8

What is volcanic activity and how does carbon move from one reservoir to another

Answer 8

• ranges from emissions of gases, non - explosive lava emissions to extremely violet explosive bursts that may last many hours
• lithosphere - atmosphere

Question 9

How does deforestation affect process and what are the consequences

Answer 9

• decrease photosynthesis
• decrease food chain transfer
• increases amount of CO2 in atmosphere
• contributes to climate change

Question 10

How does combustion of fossil fuels affect processes and what are the consequences

Answer 10

• increase combustion
• releases stored carbon into the atmosphere
• contributes to climate change

Question 11

How does afforestation affect processes and what are the consequences

Answer 11

• increases photosynthesis
• increases food chain transfer
• decreases amount of CO2 in the atmosphere

Question 12

How does intensive farming affect processes and what are the consequences

Answer 12

• increase decomposition
• can either increase or decrease photosynthesis
• increase CO2 in atmosphere

Question 13

How does pollution of oceans affect carbon processes and what are the consequences

Answer 13

• increase in CO2
• decrease in respiration
• reduce amount of CO2 released

Question 14

What are the nitrogen reservoirs

Answer 14

• atmosphere
• biosphere
• lithosphere
• hydrosphere

Question 15

What is ionisation

Answer 15

• lightning provides energy for atmospheric nitrogen and oxygen to react and produce oxides of nitrogen

Question 16

What is fixation

Answer 16

• microorganisms that can chemically reduce nitrogen to ammonia

Question 17

What is nitrogen food chain transfer

Answer 17

• nitrogen passes between organisms as amino acids and proteins in food

Question 18

What is nitrification

Answer 18

• involves the oxidation of ammonium ions to nitrites, then to nitrates, by nitrifying bacteria in the soil

Question 19

What is denitrification

Answer 19

• chemical reduction of nitrates in soil to nitrogen and nitrogen oxide gases, by denitrifying bacteria in the soil

Question 20

What is leaching

Answer 20

• the high solubility of nitrates means they are easily leached out of the soils and into water bodies where they act as nutrients for aquatic plants and algae

Question 21

What is absorption by roots nitrogen

Answer 21

• plants absorb nitrogen as soluble ions, mainly as nitrate but also as ammonium ions

Question 22

What is ammonification

Answer 22

• the amino groups in proteins are released as ammonium ions by the action of bacteria, fungi as they decompose dead organic matter

Question 23

How does the Haber process impact the nitrogen reservoirs and availability

Answer 23

• turning air into fertilisers
• use large amounts of energy
• ammonia is then converted to nitrates

Question 24

How does agricultural activities impact nitrogen reservoirs and availability

Answer 24

• use of fertilisers : nitrate fertilisers may increase problems caused by leaching
• drainage systems : makes soil more aerobic so increases the number of nitrifying bacteria
• soil disturbance : ploughing - increases rate of decomposition which releases more nitrogen oxides

Question 25

How does pollution impact nitrogen reservoirs and availability

Answer 25

- combustion releases oxides of nitrogen

Question 26

Explain the process of eutrophication

Answer 26

- nutrients are transported to a body of water - contains fertilisers - build up of nutrients cause algae blooms - stops light getting to the plants that photosynthesise - these plants die which decreases oxygen levels - water becomes anoxic - causes all organisms to die

Question 27

What are the phosphorus reservoirs

Answer 27

- animals and plants - sediments and rocks - water

Question 28

Why is phosphorus often a limiting factor in plant growth

Answer 28

- no atmosphere reservoir: slower to cycle

Question 29

What is absorption by roots with phosphorus

Answer 29

- phosphate ions in solution - solution taken up by the roots of plants - plants use it to make DNA & RNA etc

Question 30

What is food chain transfer

Answer 30

- one organism consumes another - phosphorus moves along and becomes more available

Question 31

What is decomposition

Answer 31

- living organisms die - microbes break down dead organic matter - release phosphorus back to the soil

Question 32

What is sedimentation in phosphate

Answer 32

- phosphate ends up in sediments - become rocks

Question 33

What is mountain building

Answer 33

- plate tectonics move from underground to the surface

Question 34

What is weathering/erosion

Answer 34

- rocks exposed to the surface are weathered and eroded

Question 35

What human activities causes the most impact on the movement and storage of phosphorus

Answer 35

- fertilisers : contain phosphate - mining : obtaining phosphorus from fertilisers

Question 36

Sustainable management of the carbon cycle

Answer 36

- afforestation : increase photosynthesis - reduce combustion - carbon capture

Question 37

Sustainable management of the nitrogen cycle

Answer 37

- reduce use of combustion engines in vehicles - reduce reliance of fertilisers - educate farmers on weather conditions

Question 38

Sustainable management of the phosphorus cycle

Answer 38

- increase in natural fertilisers - crop breeding programmes