Net Primary Production (NPP)

Question 1

Net primary production

Answer 1

The difference between the total amount of CO2 taken up by plants minus the CO2 lost from plant respiration

It is the balance between the carbon (CO2) gained by photosynthesis and the carbon released by plant respiration

Question 2

What is the equation for net primary production?

Answer 2

Net primary production
=
gross primary production - respiration

Question 3

What happens in Net primary production? (Plants)

Answer 3

1. Glucose is produced during photosynthesis (Gross Primary Production)
2. Some glucose used to supply energy to drive cellular processes (Respiration)
3. Remaining energy stored as biomass (Net Primary Production)

Question 4

Gross primary production (GPP)

Answer 4

the amount of energy, or ‘food’, made by plants through photosynthesis over a specific period

Question 5

Respiration

Answer 5

The amount of CO2 that is lost from an organism or system from metabolic activity

Question 6

What is different in terrestrial net primary production

Answer 6

Soil fertility creates significant variation

Ex: Temperate ecosystems are limited by Nitrogen.
Tropical ecosystems are limited by more Phosphorous.

Question 7

What is aquatic net primary production limited by?

Answer 7

Limited more by Phosphorous than Nitrogen

Question 8

What is marine net primary production limited by?

Answer 8

Primarily limited by Nitrogen

Question 9

When is the rate of biomass accumulation (NPP) highest?

Answer 9

During the initial stages of ecosystem recovery following disturbance

Question 10

What does standing crop mean?

Answer 10

The mass of living material that each trophic level has at a particular time

Question 11

How much NPP is consumed by herbivores? (Plant eating animals)

Answer 11

15%

Question 12

What increases with the rates of NPP?

Answer 12

1. Rates of consumption
2. Secondary production

Question 13

Secondary production

Answer 13

Rate of biomass production by consumers or herbivores.

Question 14

What are the physical constraints on energy transfer?

Answer 14

1. First law of thermodynamics
2. Second law of thermodynamics

Question 15

First law of thermodynamics

Answer 15

Energy cannot be created or destroyed, only transformed from one form to another

Question 16

Second law of thermodynamics

Answer 16

Energy transformations and transfers are not 100% efficient

Question 17

What are the stages of energy transfer?

Answer 17

1. Solar Energy
2. Photosynthesis
3. Chemical Energy

Question 18

What are the efficiencies involved with consumption?

Answer 18

1. Ingestion efficiency
2. Assimilation efficiency
3. Production efficiency

Question 19

Ingestion efficiency

Answer 19

Energy ingested / Energy available

• Scraps are left because unable to eat carcass - bones

Question 20

Assimilation efficiency

Answer 20

Energy assimilated / Energy ingested

• We don’t consume all of the energy in foods we eat b/c we get rid of it in our waste (poop)

Question 21

Production efficiency

Answer 21

Energy utilized in production / Energy assimilated

• Biomass consumed that actually ends up being stored

Question 22

Efficiencies are a function of?

Answer 22

Food item and the consumer

Question 23

What affects ingestion, assimilation, and production efficiencies?

Answer 23

The amount of energy available for secondary production

Question 24

Implications of thermodynamics

Answer 24

• Food chains are short
• Most consumers are generalists
• Omnivory is common (Consume plants + animals)
• Primary production > 1º consumer prod. > 2º consumer prod. , etc.