Net primary productivity

Definition

Net primary productivity (NPP) is the rate at which all the plants in an ecosystem produce net useful chemical energy. It is equal to the gross primary productivity (GPP) minus the energy used by the plants for respiration (R).

5 Must Know Facts For Your Next Test

1. NPP represents the amount of biomass available for consumption by herbivores and decomposers.
2. It is a critical factor in determining the energy flow through an ecosystem.
3. Tropical rainforests typically have high NPP, while deserts generally have low NPP.
4. NPP can be influenced by factors such as light availability, temperature, and nutrient availability.
5. It is measured in units of mass per unit area per unit time, usually grams of carbon per square meter per year (g C/m²/yr).

Review Questions

• What factors can influence net primary productivity in an ecosystem?
• How does net primary productivity differ between tropical rainforests and deserts?
• Why is net primary productivity important for understanding energy flow in ecosystems?

Related terms

Gross Primary Productivity (GPP): The total amount of chemical energy produced by photosynthesis before any is used for respiration.

Respiration (R): The process by which plants use some of their produced energy for maintenance and growth.

Biomass: The total mass of living organisms within a given area or ecosystem at a given time.