4.3 carbon cycling

Question 1

4 forms of carbon

Answer 1

1. organic compounds
2. atmospheric gases
3. carbonates
4. non-living remains

Question 2

4 main sinks of carbon

Answer 2

1. hydrosphere (water)
2. lithosphere (ground)
3. atmosphere (air)
4. biosphere (living things)

Question 3

carbon in the biosphere (plants)

Answer 3

• autotrophs convert CO2 into organic carbon compounds
• these carbon compounds then move across the food web

Question 4

carbon in aquatic ecosystems

Answer 4

• CO2 dissolves in aquatic ecosystems, such as the ocean
• reacts with water to form hydrogen carbonate ions
• animals such as reef-building corals + mollusca use this carbonate to build hard parts (calcium carbonate)
• these parts can become fossilized in limestone

Question 5

peat

Answer 5

• peat forms when organic matter (plants) is not fully decomposed bc of acidic and/or anaerobic conditions in water-logged soil
• peatlands include bogs, wetlands

Question 6

fossil fuels

Answer 6

partially decomposed organic matter from past geological eras was converted either into coal or oil+gas that accumulates in porous rock

Question 7

sources of atmospheric carbon

Answer 7

respiration, anaerobic respiration, combustion

Question 8

how does carbon come from respiration?

Answer 8

carbon dioxide gas is produced and diffuses out of the organism into its environment (water/atmosphere)

Question 9

how does carbon come from anaerobic respiration? (methanogenesis)

Answer 9

methanogenic archaeans decompose organic matter in anaerobic environments. methane (CH4) is produced (soil/atmosphere).
- in the presence of oxygen (atmosphere) methane is oxidized into CO2 and H2O

Question 10

how does carbon come from combustion?

Answer 10

1. organic matter (biomass [wood, peat, biofuels] & fossil fuels) is burned
2. carbon dioxide is released into the atmosphere

Question 11

draw carbon cycle diagram

Answer 11

see ipad

Question 12

fill in carbon cycle diagram

Answer 12

see ipad

Question 13

autotroph

Answer 13

an organism that produces complex organic compounds using carbon from simple substances such as carbon dioxide, generally using energy from light or inorganic chemical reactions

Question 14

examples of autotrophs

Answer 14

plants and algae