Productivity stands for the total increase in the mass (phytomass). The productivity of an ecosystem is defined as the rate of production of the amount of matter (organic) formed or evolved per unit area in time.Gross primary productivity is the defined as the rate at which the main chemical energy producers (plants) produces the chemical energy, whereas, net primary productivity is defined as the total amount of chemical energy stored by the main chemical energy producers (plants). The main difference between GPP and NPP is the production and storage of chemical energy. GPP is the production of useful chemical energy that is being used to carry out the processes whereas, NPP is chemical energy that is not being used but stored. So, we can say that NPP is the total stored or incoming energy of main chemical producers while the GPP is the total expended or outgoing energy of the main chemical producers. GPP can affect NPP while NPP cannot affect GPP.
What is Gross Primary Productivity?
GPP stands for gross primary productivity. Gross primary productivity or GPP is the net amount of energy that is produced by the main energy producers of the ecosystem in a particular area during the specific time. GPP tends to state the total productivity. In other words, GPP is said to the total amount of energy produced by the green plants. It mainly depends on the chlorophyll content of the plant. Another thing to be noted that GPP has no other factors that can decrease its rate due to which it is a continuous process or productivity. GPP is the rate of organic matter formed by the energy producers (plants) + the rate of respiration of energy producers (plants).
What is Net Primary Productivity?
NPP stands for net primary productivity. 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.
Gross Primary Productivity vs. Net Primary Productivity
- GPP stands for gross primary productivity while NPP stands for net primary productivity.
- GPP is the total amount of energy produced in the process, whereas NPP is the total difference between GPP and the energy used by the producer for respiration.
- GPP has an effect on NPP, but NPP has no effect on GPP.
- GPP is the total production while NPP is the total energy consumption.
- GPP is totally dependent on chlorophyll content of the plant, but NPP is independent of chlorophyll
- GPP gives us the total outgoing energy in the system, whereas NPP gives us the total incoming energy in the system.
- GPP is concerned with total productivity and counter to this NPP is net productivity.