Primary productivity is the rate of capture of solar energy or biomass production of the producers which occur through the process of photosynthesis or chemosynthesis.
It is divided into two types:
GROSS PRIMARY PRODUCTIVITY (GPP): rate of production or total production of organic matter during photosynthesis in a given length of time.
and
NET PRIMARY PRODUCTIVITY (NPP): remaining biomass or the energy left after utilization of producers i.e., NPP = gross primary productivity (GPP) – respiration losses (R)
