Concept of Ecosystem - Productivity

Net Primary Productivity (NPP) = Gross Primary Productivity (GPP) - Respiratory loss by plants (R)

• Productivity is the rate of formation of biomass (organic matter) at any trophic level per unit area over time, mainly through photosynthesis or chemosynthesis. Unit: g m⁻² yr⁻¹ or g m⁻² day⁻¹.
• Primary productivity is the amount of biomass produced by plants; it includes Gross Primary Productivity (total production) and Net Primary Productivity (usable biomass left after plant respiration).
• Net Primary Productivity (NPP) is important because it represents the energy available to herbivores and other consumers in the ecosystem.
• Secondary productivity is the rate of formation of organic matter by consumers (heterotrophs) and depends on primary productivity.
• Productivity varies across ecosystems depending on factors like plant species, nutrient availability, climate, and photosynthetic efficiency; globally, oceans contribute a significant share.