What is the primary productivity of an ecosystem

Primary Productivity ... In other words, it is the rate at which energy is stored as biomass by plants and other primary producers, and that is available to consumers of the ecosystem

In ecology, the term productivity refers to the rate of generation of biomass in an ecosystem, usually expressed in units of mass per volume (unit surface) per unit of time, such as grams per square metre per day (g m−2 d−1). The unit of mass can relate to dry matter or to the mass of generated carbon.