Net primary productivity

Definition

Net primary productivity (NPP) is the rate at which plants in an ecosystem produce net useful chemical energy. It is the difference between the total energy captured through photosynthesis and the energy used by plants for respiration.

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 usually measured in units of mass per unit area per time (e.g., grams per square meter per year).
3. NPP varies widely among different ecosystems; tropical rainforests have high NPP, while deserts have low NPP.
4. Factors such as sunlight, temperature, water availability, and nutrient levels can affect NPP.
5. NPP is a critical component in understanding the carbon cycle and energy flow within ecosystems.

Review Questions

• What is net primary productivity and why is it important in an ecosystem?
• How does net primary productivity differ between various types of ecosystems?
• Which factors can influence the rate of net primary productivity?

Related terms

Gross Primary Productivity (GPP): The total amount of energy captured by photosynthesis before accounting for plant respiration.

Respiration:

The process by which plants convert some of the energy captured during photosynthesis into usable energy, releasing carbon dioxide.

Biomass: The total mass of living organisms in a given area or volume, often used as a measure of ecosystem productivity.