Question

What does the equation NPP = GPP − R represent?

A.
It represents the amount of chemical energy that will be available to consumers.
B.
It represents the amount of chemical energy that will not be available to consumers.
C.
It represents the amount of solar energy that will be available to consumers.

Answer 1

The equation NPP = GPP - R represents option B, the amount of chemical energy that will not be available to consumers.

NPP stands for net primary productivity, which is the amount of energy that is available to the primary consumers in an ecosystem after the energy used by the producers (GPP - gross primary productivity) for their own metabolic needs (R - respiration) is subtracted.

Therefore, NPP is the energy that is left over after the producers have met their own needs, and it is available for consumption by the consumers in the ecosystem. The equation shows that not all of the energy that is produced by the plants through photosynthesis is available for consumption by the consumers. Some of it is used by the plants themselves for their own metabolic processes.