What do primary producers have available to convert into biomass?

Secondary productivity is the rate of synthesis of organic matter and contained by the transfer of energy through food chain and the production is very slow. The energy that has been used for respiration cannot be converted into biomass.

Gross primary productivity is the total organic matter that is synthesized by producers in the process of photosynthesis per unit time and area.

Hence, primary producers have net primary productivity to convert into biomass.

Net primary productivity is the amount of organic matter stored by producers per unit time and per unit area and it is the difference between total photosynthesis and respiration in the ecosystem.

It is calculated by quantifying new organic matter produced and retained in a given period by living plants.