Nutrient cycling

Question 1

What is nutrient cycling?

Answer 1

Provides elements for metabolic processes and helps with the construction of organic molecules.

Question 2

What are decomposers

Answer 2

Bacteria and fungi that absorb organic nutrients from dead organisms and waste from living organisms, converting them into organic molecules.

Leaf litter-> Humus

Question 3

What is the role of decomposers?

Answer 3

Provides mineral and nutrients for metabolism.

Question 4

Detritivores

Answer 4

Organisms living in or on the soil that feed and gain nutrients from detritus (dead plant).

Question 5

Factors that effect rate of decomposition

Answer 5

Type of organic matter present

Number and types of decomposers and detritivores

Environmental conditions of Temperature, O2 content, Moisture

Question 6

What are the two components of each cycle?

Answer 6

Geochemical and biological

Question 7

What are the stages for cycling nitrogen?

Answer 7

Nitrogen fixation
Assimilation
Ammonification
Nitrification

Question 8

Why is nitrogen needed in plants? And how is it taken in?

Answer 8

Enzymes
Nucleic acid
Amino acids
(Cytoskeleton)

All taken in through the roots.

Question 9

What is Putrefaction/ammonification?

Answer 9

Bacteria and fungi, decompose dead plants and animals, faeces and urine into ammonia ions.

Question 10

What is Nitrification?

Answer 10

The ammonia formed in putrefaction is converted to nitrite to nitrate via nitrification.

Question 11

What bacteria’s are involved in Nitrification?

Answer 11

Ammonia -> Nitrite (NO2) is Nitrosomonas

nitrite -> nitrate (NO3) is nitrate (nitrobacter)

Question 12

What is Nitrogen fixation?

Answer 12

Atmospheric nitrogen can be converted into nitrogen compounds.

This can be done by free living bacteria or symbiotic nitrogen fixing bacteria. (Rhizobium found in peas or azotobacter in soil)

Question 13

What is Denitrification?

Answer 13

Nitrogen is lost from ecosystems via this process. This may happen in water logged soils with anaerobic conditions. (Pseudomonas can convert nitrates and ammonium ions back to nitrogen)

Question 14

Ways to fix nitrogen>

Answer 14

Nitrogen fixing bacteria

Lightning