Question

Define the terms:
a. Gross Primary Productivity
b. Net Primary Productivity

Hint:

GPP includes all photosynthetic output; NPP is what remains for herbivores after plant respiration.

Answer 1

a. Gross Primary Productivity (GPP): The total rate of photosynthesis, including the organic matter used up by plants in respiration, measured as the amount of organic matter or energy produced per unit area per unit time.
b. Net Primary Productivity (NPP): The rate of organic matter stored by plants after accounting for losses due to respiration, expressed as \( \text{NPP} = \text{GPP} - \text{Respiration losses} \). It represents the biomass available for consumers.
Answer: GPP is total photosynthetic production; NPP is GPP minus respiration losses.