Definitions
Define Gross productivity (GP)
The total gain in energy or biomass per unit area per unit time, which could be through photosynthesis in primary producers or absorption in consumers.
Define net secondary productivity (NSP)
The gain by consumers in energy or biomass per unit area per unit time remaining after allowing for respiratory losses (R).
Using the net primary productivity (NPP) equation of NPP = gross primary productivity (GPP) - Respiration, solve this scenario:
Suppose plants in an old field ecosystem convert a total of 4 kg C/m^2/yr of energy during photosynthesis and use 1 kg C/m^2/yr for metabolic needs.
What is Gross Primary Productivity?
What is Net Primary Productivity?
What is the Net Production Efficiency (converted energ available for growth/total energy converted X 100)?
4 kg C/m^2/yr
Define gross primary productivity (GPP)
The total gain in energy or biomass per unit area per unit time fixed by photosynthesis in green plants.
Define primary productivity
The gain by producers in energy or biomass per unit area per unit time. This term could refer to either gross or net primary productivity.
Using the net primary productivity (NPP) equation of NPP = gross primary productivity (GPP) - Respiration, solve this scenario:
Suppose plants in an old field ecosystem convert a total of 4 kg C/m^2/yr of energy during photosynthesis and use 1 kg C/m^2/yr for metabolic needs.
What is Net Primary Productivity?
3 kg C/m^2/yr
Define gross secondary productivity (GSP)
The total gain by consumers in energy or biomass per unit area per unit time through absorption.
Define secondary productivity
The biomass gained by heterotrophic organisms, through feeding and absorption, measured in units of mass or energy per unit area per unit time.
Using the net primary productivity (NPP) equation of NPP = gross primary productivity (GPP) - Respiration, solve this scenario:
Suppose plants in an old field ecosystem convert a total of 4 kg C/m^2/yr of energy during photosynthesis and use 1 kg C/m^2/yr for metabolic needs.
What is the Net Production Efficiency (converted energy available for growth/total energy converted X 100)?
75%
Define net productivity (NP)
The gain in energy or biomass per unit area per unit time remaining after allowing for respiratory losses (R). Other metabolic losses may take place, but these may be ignored when calculating and defining net productivity for the purpose of this course.
Define net primary productivity (NPP)
The gain by producers in energy or biomass per unit area per unit time remaining after allowing for respiratory losses (R). This is potentially available to consumers in an ecosystem.