Question

The net primary productivity is the a total amount of plant b- -Organic matter available as food c- Total mass of biological life

a

Answer 1

Net primary productivity = a - c

------------------------

Net Primary Productivity (NPP) is the amount of carbon uptake after subtracting Plant Respiration (RES) from Gross Primary Productivity (GPP). GPP is the total rate at which the ecosystem capture and store carbon as plant biomass, for a given length of time.

NPP = GPP – RES

Net primary productivity or NPP is defined as the net amount of energy that is stored by the main energy producers of the ecosystem per unit area in unit time. NPP tends to state the total difference between GPP and the energy used by the producer for respiration. In other words, NPP is said to be the total amount of energy stored by the green plants. It doesn’t depend on the chlorophyll content of the plant. NPP is equal to the gross primary productivity – rate of respiration.

Comparison Chart

	Gross Primary Productivity	Net Primary Productivity
Abbreviation	GPP stands for gross primary productivity.	NPP stands for net primary productivity.
Definition	Gross Primary Productivity is the total amount of energy produced in the process.	Net Primary Productivity is the total difference between GPP and the energy used by the producer for respiration.
Affect	GPP has a direct effect on NPP.	NPP has no effect on GPP.
Chlorophyll	GPP is totally dependent on chlorophyll content of the plant.	NPP is not dependent on the chlorophyll content.
Outgoing & Incoming energy	GPP gives us the total outgoing energy in the system.	NPP gives us the total incoming energy in the system.