which of the following describes the amoutn of organic material that is available for transfer to the next trophic level after subtracting amterial used for respiration
The amount of organic material that is available for transfer to the next trophic level after subtracting the material used for respiration is described as net primary productivity (NPP). NPP represents the rate at which all the plants in an ecosystem produce net useful chemical energy; it is equal to the difference between the rate at which the plants in an ecosystem produce useful chemical energy (gross primary productivity, or GPP) and the rate at which they use some of that energy during respiration.
Here's the formula:
NPP = GPP - R
where:
- NPP is net primary productivity,
- GPP is gross primary productivity, and
- R is the energy used by plants for respiration.
Net primary productivity is an important metric in ecology because it is the energy source for all other organisms in the ecosystem. Only energy that has not been used by plants for their own metabolic processes (respiration) is available for consumers (herbivores, and subsequently carnivores and decomposers) in the ecosystem.