Gross primary production
A)is equal to NPP - respiration of autotrophs.
B)is about half of NPP.
C)is the total biomass of all photosynthetic autotrophs.
D)is the total energy from light converted to chemical energy of organic molecules per unit time.
E)is not as important as net primary production.

Question

Quizplus · Accepted Answer

Gross primary production (GPP) is the total amount of organic matter produced by plants through photosynthesis in a given area and time period. It is expressed in units of energy per unit area per unit time (e.g., kJ/m2/year). GPP includes the energy produced during photosynthesis that is consumed during plant respiration (R), referred to as autotrophic respiration. Therefore, the net primary production (NPP) is equal to GPP minus R. Hence, option A is incorrect. GPP is greater than NPP because GPP includes the energy that is lost in R. Therefore, option B is incorrect. GPP includes the organic material produced by all photosynthetic autotrophs, including microscopic algae, rooted submerged aquatic plants, and emergent plants, in addition to herbaceous and woody plants. Therefore, option C is incorrect. GPP is a critical component of the carbon cycle and serves as the foundation for all trophic processes in ecosystems. Thus, it is essential for understanding ecosystem functioning and productivity. Thus, option E is incorrect.

Gross Primary Production