Ecology - Carbon + Nitrogen Cycle

Question 1

The natural process of carbon cycle

Answer 1

CO2 in air by respiration + combustion of fossil fuels

Photosynthesis: CO2->O2 for respiration. Re use co2

Allow for plant + animal growth

Question 2

Role of saprophyte in carbon cycle

Answer 2

Cause decay in dead organism to release co2

Question 3

Formation of fossil fuel + gas

Answer 3

-In anaerobic environment or place with no saprophyte, if organism die, get into the ground
-pressure from rock layers compact left over to fossil fuel

-gas when underwater

Help with less co2 release

Question 4

Negative human intervention in carbon cycle

Answer 4

-burning fossil fuels = co2 release
-deforestation with fire = stored co2 released, less photosynthesis, animal no food = death and decompose

-co2 cause greenhouse effect, heat trapped on earth - more animal die

Question 5

Nitrogen cycle - uses + natural cycle

Answer 5

Formation of amino acid + nucleotide

Plants obtain from soil, animal from consumption

Question 6

1) Nitrogen fixation + ammonification

Answer 6

-Nitrogen gas (N2) from air covert to ammonium (NH4) by bacteria Azotubacter (in soil) + Rhizobium (in nodule of plants root, mutualism + more aminos acid).
-Both aerobes, addition of H

Ammonification - saprophyte (decomposers)break down large molecule containing N into ammonia (NH3)

Question 7

2) Nitrification

Answer 7

Ammonium/ ammonia -> Nitrite (NH2) by Nitrosonomas bacteria

Nitrite -> Nitrate by Nitrobacter bacteria

Both aerobes

Question 8

3) De-nitrification

Answer 8

Nitrate -> Nitrogen gas by Pseudomonas bacteria, anaerobic
-uses o2 for respiration

Question 9

Negative human intervention - Eutrofication

Answer 9

Overuse of fertiliser (eg nitrate), nitrate run off via dissolved in rain water and go to water source (pond)

1)Ions on pond promote growth of Algae rapidly
2)blocks sunlight for photosynthesis, plant dies (low o2+co2) pH lowers
3)animal die from no food source + algae die from no ions left
4)decomposers bacteria use o2 to decay organism (increase co2 + decrease pH in water)
5)dead zone created (organism die if get there)

Question 10

Positive human interventions

Answer 10

-Use solid fertiliser (manure) instead of spray (avoid dissolve in water)
-use fertiliser away from water source
-use less fertiliser

Question 11

How to increase nitrogen content in soil to promote growth

Answer 11

Drain soil so not water logged (no o2 = anaerobic environment for pseudomonas)

Turn over soil to let o2 in (nitrogen fixing + nitrification bacteria more optimum)