Question

What is the relationship between Gross Primary Productivity (GPP) and Net Primary Productivity (NPP)?

Options

• GPP equals NPP because there are no respiratory losses

• NPP is always greater than GPP in natural ecosystems

• GPP is derived from NPP by adding consumer respiration

• NPP = GPP − Respiratory loss by plants (R)

Answer 1

The formula NPP = GPP − R clearly establishes that Net Primary Productivity is obtained by subtracting the respiratory losses (R) of producers from their Gross Primary Productivity. This relationship shows that GPP always exceeds NPP because plants consume a portion of their photosynthetic output through respiration.